Posts Tagged ‘Supercharger’
May 14th, 2011 | 
Author: 
MJ Marks asked:
At one time, if I asked, what exactly are twin turbo kits? The fact that I didn’t know could be attributed to the fact that I am a girl. But saying something like that today would not go over well in an equal rights, girl’s can do anything, type of society. So I will blame my ignorance on lack of interest, the fact that I didn’t get my license until I was 21, and that I have a minor in Nature and Wilderness Conservation and consider excess noises and lights a form of pollution. So, when I hear the words twin turbo kits, I think loud, fast cars. But is this correct? And if so, is there more to them?
With just a little research, I discovered that my basic concept of twin turbo kits are correct. They give your car a huge boost of power along with loudness. And let’s face it, a lot of people like the roar of a fast car! Here in our small town last weekend there was a 50′s car show called Lost in the 50′s. It is a huge event in our small town and begins with a vintage car parade on Friday night. Our whole family went in to see it, and the roaring of supped up engines was one of the biggest hits.
To break down more specifically what twin turbo kits are, let’s look at each term individually.
Let’s first look at the second word, turbo, which is short for turbocharger. A turbocharger forces compressed air into an internal combustion engine. It is a type of supercharger in which the compressor is powered by a turbine which is driven by the engine’s own exhaust gases (so you can tell your neighbor that you are recycling!). With the air compressed as it enters the engine, it creates more power.
Now let’s back up. Obviously, twin means two, but two what? Two turbochargers, which can come in one of two different configurations: parallel or sequential.
Basically, parallel are two identical turbos that are smaller than a single turbo, and that both turn on at the same time. With the two smaller turbos, the duty of compressing the intake charge is completed faster, so they reach their boost threshold more quickly than a single large turbo, but produce the same amount of boost.
A sequential twin turbo system is a lot more complicated. Basically, one turbo is active throughout the entire rev range, and the second one only kicks in at the higher RPM. This system also has reduced turbo lag (the time it takes to spool the turbine enough for it to operate effectively), but has the added benefit of adding extra boost at higher RPM’s. Similar performance with less lag is the primary benefit of twin turbo kits over a bigger single turbo system.
Kit, well we all know what that means, it is the twin turbo system bundled up with everything you need to turbo charge your car.
So, if you like your cars loud and fast, then turbo charging your car may be just the thing for you. And if there is one thing I learned at the vintage car parade, it is that any car can be turbo charged! I expected to see twin turbo kits on muscle cars of the 1960′s, but I also saw car’s with them from as early as the 1920′s. And though you may not get to use your turbo charger every day, there are definite moments in time when they can be a lot of fun.
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At one time, if I asked, what exactly are twin turbo kits? The fact that I didn’t know could be attributed to the fact that I am a girl. But saying something like that today would not go over well in an equal rights, girl’s can do anything, type of society. So I will blame my ignorance on lack of interest, the fact that I didn’t get my license until I was 21, and that I have a minor in Nature and Wilderness Conservation and consider excess noises and lights a form of pollution. So, when I hear the words twin turbo kits, I think loud, fast cars. But is this correct? And if so, is there more to them?
With just a little research, I discovered that my basic concept of twin turbo kits are correct. They give your car a huge boost of power along with loudness. And let’s face it, a lot of people like the roar of a fast car! Here in our small town last weekend there was a 50′s car show called Lost in the 50′s. It is a huge event in our small town and begins with a vintage car parade on Friday night. Our whole family went in to see it, and the roaring of supped up engines was one of the biggest hits.
To break down more specifically what twin turbo kits are, let’s look at each term individually.
Let’s first look at the second word, turbo, which is short for turbocharger. A turbocharger forces compressed air into an internal combustion engine. It is a type of supercharger in which the compressor is powered by a turbine which is driven by the engine’s own exhaust gases (so you can tell your neighbor that you are recycling!). With the air compressed as it enters the engine, it creates more power.
Now let’s back up. Obviously, twin means two, but two what? Two turbochargers, which can come in one of two different configurations: parallel or sequential.
Basically, parallel are two identical turbos that are smaller than a single turbo, and that both turn on at the same time. With the two smaller turbos, the duty of compressing the intake charge is completed faster, so they reach their boost threshold more quickly than a single large turbo, but produce the same amount of boost.
A sequential twin turbo system is a lot more complicated. Basically, one turbo is active throughout the entire rev range, and the second one only kicks in at the higher RPM. This system also has reduced turbo lag (the time it takes to spool the turbine enough for it to operate effectively), but has the added benefit of adding extra boost at higher RPM’s. Similar performance with less lag is the primary benefit of twin turbo kits over a bigger single turbo system.
Kit, well we all know what that means, it is the twin turbo system bundled up with everything you need to turbo charge your car.
So, if you like your cars loud and fast, then turbo charging your car may be just the thing for you. And if there is one thing I learned at the vintage car parade, it is that any car can be turbo charged! I expected to see twin turbo kits on muscle cars of the 1960′s, but I also saw car’s with them from as early as the 1920′s. And though you may not get to use your turbo charger every day, there are definite moments in time when they can be a lot of fun.
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Posted in Advantages And Disadvantages Of Twin Turbo Kits | 
Tags: Car Parade, Exhaust Gases, Internal Combustion Engine, Lack Of Interest, Loudness, Neighbor, Pollution, Recycling, Roar, Second Word, Supercharger, Turbine, Turbos, Vintage Car, Wilderness Conservation | 
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asked:
Many cars on the road these days are marketed as coming with TSI, TDI, or DSG features. However, for people who are unfamiliar with these terms, the process of choosing a car to drive can seem rather daunting. This article will describe the differences between cars marketed as TSI, TDI, and DSG.
First, TDI is shorthand for turbocharged direct injection; this is a way turbo diesel engines may be designed. The design includes both cylinder direct fuel injection and turbo charging. Direct injection refers to the process in an engine through which fuel is sprayed from a fuel injector into the combustion chambers of each cylinder in an engine. The fuel is atomized, and the process here may be contrasted with that in an older diesel engine, where indirect injection is used. Forced induction through a turbocharger can also be used by the engine so more air is then able to find its way to the cylinders of the engine.
Intercoolers are also frequently used in these engines to increase the density of compressed air that enters from the turbo; this is done by lowering the air temperature. As a result of the compressed air and the increases in fuel injection and combustion, greater engine efficiency and power outputs are possible in comparison to petrol engine counterparts. Similarly, emissions are decreased and torque is increased in comparison to petrol engines that are not turbo charged or directly injected.
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Second, TSI is shorthand for petrol engines that feature both twin charger and fuel stratified injection technology. The twin charger is composed of both a turbo charger and a super charger. The term TSI may also be used to describe engines that include fuel stratified injection and a turbocharger but not a supercharger; however, the more common use involves the combination of fuel stratified injection and the twin charger.
As you can see, differences between TDI engines and TSI engines start with the fact that TDI engines are powered by diesel while TSI engines are powered by petrol. Since petrol usually costs less than diesel per gallon, it will cost less to fill up a vehicle that uses a TSI engine than one that uses a TDI engine, presuming the same amount of fuel is added to both.
However, because diesel fuel carries more energy than petrol fuel and diesel engines are more efficient than petrol engines, in the long run, it will take less fuel to propel a TDI engine a particular distance than a similar sized TSI engine. Similarities between both engines include the fact that both make use of turbo chargers. Both also make use of direct injection of fuel, although it is known as direct cylinder injection in TDI engines and as fuel direct injection or fuel stratified injection.
Third, DSG is shorthand for the direct shift gearbox. The direct shift gearbox is a dual clutch multiple shaft manual gearbox that is controlled by the computer within the car’s engine; the design involves a transaxle but does not involve a conventional clutch pedal. As a result, full automatic and semi manual controls are included. To put things another way, a DSG essentially involves two independent manual gearboxes and clutches that are housed in a single housing and chained to work together as a single unit.
The design of two independent clutches allows for faster shifting times while eliminating the need for a torque converter that is present in a conventional automatic transmission design. The DSG differs from TDI and TSI in that it is a transmission design rather than an engine design, and it may be used in both TSI and TDI cars.
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Many cars on the road these days are marketed as coming with TSI, TDI, or DSG features. However, for people who are unfamiliar with these terms, the process of choosing a car to drive can seem rather daunting. This article will describe the differences between cars marketed as TSI, TDI, and DSG.
First, TDI is shorthand for turbocharged direct injection; this is a way turbo diesel engines may be designed. The design includes both cylinder direct fuel injection and turbo charging. Direct injection refers to the process in an engine through which fuel is sprayed from a fuel injector into the combustion chambers of each cylinder in an engine. The fuel is atomized, and the process here may be contrasted with that in an older diesel engine, where indirect injection is used. Forced induction through a turbocharger can also be used by the engine so more air is then able to find its way to the cylinders of the engine.
Intercoolers are also frequently used in these engines to increase the density of compressed air that enters from the turbo; this is done by lowering the air temperature. As a result of the compressed air and the increases in fuel injection and combustion, greater engine efficiency and power outputs are possible in comparison to petrol engine counterparts. Similarly, emissions are decreased and torque is increased in comparison to petrol engines that are not turbo charged or directly injected.
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Second, TSI is shorthand for petrol engines that feature both twin charger and fuel stratified injection technology. The twin charger is composed of both a turbo charger and a super charger. The term TSI may also be used to describe engines that include fuel stratified injection and a turbocharger but not a supercharger; however, the more common use involves the combination of fuel stratified injection and the twin charger.
As you can see, differences between TDI engines and TSI engines start with the fact that TDI engines are powered by diesel while TSI engines are powered by petrol. Since petrol usually costs less than diesel per gallon, it will cost less to fill up a vehicle that uses a TSI engine than one that uses a TDI engine, presuming the same amount of fuel is added to both.
However, because diesel fuel carries more energy than petrol fuel and diesel engines are more efficient than petrol engines, in the long run, it will take less fuel to propel a TDI engine a particular distance than a similar sized TSI engine. Similarities between both engines include the fact that both make use of turbo chargers. Both also make use of direct injection of fuel, although it is known as direct cylinder injection in TDI engines and as fuel direct injection or fuel stratified injection.
Third, DSG is shorthand for the direct shift gearbox. The direct shift gearbox is a dual clutch multiple shaft manual gearbox that is controlled by the computer within the car’s engine; the design involves a transaxle but does not involve a conventional clutch pedal. As a result, full automatic and semi manual controls are included. To put things another way, a DSG essentially involves two independent manual gearboxes and clutches that are housed in a single housing and chained to work together as a single unit.
The design of two independent clutches allows for faster shifting times while eliminating the need for a torque converter that is present in a conventional automatic transmission design. The DSG differs from TDI and TSI in that it is a transmission design rather than an engine design, and it may be used in both TSI and TDI cars.
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Posted in Uncategorized |
Tags: Cat Channel, Combustion Chambers, Combustion Engine, Diesel Engine, Dsg, Fuel Injection, Fuel Injector, Google, Many Cars, Power Outputs, Shorthand, Supercharger, Turbo Charger, Turbo Diesel Engines, Turbocharger |
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Dylan G asked:
i have a 89 chevy 350 tbi and i am thinkin bout putting twin turbo chargers on it while i save up to buy a supercharger. how much more horsepower will i get out of it. it is completely stock right now. thank you
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i have a 89 chevy 350 tbi and i am thinkin bout putting twin turbo chargers on it while i save up to buy a supercharger. how much more horsepower will i get out of it. it is completely stock right now. thank you
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Posted in Maintenance & Repairs |
Tags: Chevy 350, Horsepower, Stock, Supercharger, Tbi, Turbo Chargers, Twin Turbo |
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Rudy asked:
im thinking of buying a 2003 mustang gt and i want to know if it comes supercharged because if t does im taking off the supercharger and installing 1 80 mm turbo from garrett; also if you have any suggestions weather i should install bigger turbo or not i would appreciate it
i know how to do a turbo build and all the parts needed, i just wasn’t sure if i should turbo or supercharge my gt. im mor of a turbo person so im leaning more towards the turbo. btw, this is my 3rd turbo build
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im thinking of buying a 2003 mustang gt and i want to know if it comes supercharged because if t does im taking off the supercharger and installing 1 80 mm turbo from garrett; also if you have any suggestions weather i should install bigger turbo or not i would appreciate it
i know how to do a turbo build and all the parts needed, i just wasn’t sure if i should turbo or supercharge my gt. im mor of a turbo person so im leaning more towards the turbo. btw, this is my 3rd turbo build
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Posted in Uncategorized |
Tags: 2003 Mustang, Btw, Garrett, Mor, Mustang Gt, Supercharger, Weather |
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Haitham Alhumsi asked:
The first time I ever heard of twin charging (using both a turbocharger and a supercharger on the same motor) was probably back in year 2000. At that time I was very interested in performance for the Toyota Celica and naturally I also read a lot about its sister cars (that shared some of the same engines) such as the Camry and the MR2.
One of the most interesting aftermarket parts I ran across at the time was the HKS turbo kit for the 4AGZE powered 1st generation mr2. The 4agze (for those that are not familiar with Toyota engines) is a peppy 170 horsepower 1.6 liter engine powered by the Toyota SC-12 roots type supercharger. On this car Toyota used an electromagnetically clutched supercharger that could be disabled during low power requirements such as cruising, and engaged when the user demands it.
One of the most important parts of the HKS kit is the bypass valve. This valve was used to direct air from the supercharger to the engine at lower rpm/flow points. Once the rpm’s rise, and the engine starts to demand more air, and the turbocharger is fully spooled, the valve switches over gradually till the turbocharger alone is feeding the engine while the supercharger is completely bypassed. The twin-charged MR2′s were rumored to break the 300hp mark in some cases, depending on the final boost level and the supporting modifications, and this level of power for a 1.6 litre motor at the time was quiet astounding.
The theory behind this kind of system is to use a small positive displacement (roots style) supercharger. Supercharger performance efficiency is typically at its highest at lower engine and supercharger rpm’s (for example from idle to 4000 rpm’s). Above 4000 rpm’s the supercharger’s performance and efficiency starts to drop, the horsepower required to drive it starts to rise exponentially, and the air temperature coming out of the supercharger starts to rise dramatically limiting performance.
On the other hand, using a generously sized turbocharger will allow us to feed the engine efficiently with cooler air (than that from an overworked supercharger) and maintain high rpm performance. The problem with using a larger turbocharger is that a generously sized turbocharger typically doesn’t spool before 3000 to 4000 rpm’s giving us a limited power band and thus providing no performance boost at lower rpm’s.
The idea of twin charging is to use both a supercharger and a turbocharger to have each charger do what it does best, have the supercharger boost the motor for low end torque, and as it runs out of steam, the turbocharger comes online to carry us through to redline.
There are three aspects to these types of systems that make them prohibitive to most tuners:
1. Cost and complexity: Having a complete supercharger system as well as a complete turbocharger system on the same vehicle is a lot of money to spend and a lot of parts to deal with and diagnose in case something does go wrong.
2. The bypass valve used to bypass the supercharger (and yet hold in all the air pressure coming from the turbocharger) as well as being able to control this valve electrically or mechanically requires a custom made one off valve that isn’t quite available off the shelf. Although as I write this it seems possible to find a large sized dual chamber bypass valve plumbed to operate on the differential pressure between the turbo outlet and the supercharger outlet to switchover once the turbocharger pressure = the supercharger pressure + the tension of the bypass valve opening mechanism.
3. Since we are using two different types of chargers with two different efficiency maps, it can get very complicated to figure out how to tune the motor (especially with much simpler fuel injection systems that were used at the time) because the air density can vary dramatically at the same rpm point and pressure level depending on which charger is feeding air to the motor and at what proportion. This is also where the HKS turbo kit for the 4agze was at its weakest, namely at smoothing the transition point fueling between the supercharger to turbocharger switchover.
One of the things that has changed over the last 10 years is the availability (and proliferation of knowledge) about available alternative fuels or octane boosters. Two such options are:
1- E85 fuel which is comprised of 85% Ethanol which has an octane rating of about 100 to 105 octane vs the typical 87 to 93 octane pump gasoline.
2- Water / methanol injection systems that can be used either as supplemental fueling system (based on the methanol content which carries an octane rating of 110 octane or higher) or can be used for in cylinder cooling when the water vapor injected with the methanol transforms into steam inside the combustion chamber, thus extracting lots heat out of the combustion chamber, and thus slowing down the speed of travel of the combustion flame front simulating the effects similar to those of a higher octane gasoline.
With the availability of these octane increasing or octane simulating concoctions, it has become more accessible of recent for the performance enthusiast to build a different type of twin charger system that does not require a bypass valve.
In this type of system the supercharger outlet is routed to feed the turbocharger inlet or vice versa. Rather than either the supercharger or the turbocharger feeding the engine individually (in parallel operation) and switching between the two, we are now using a two stage compression system where one stage is the factory supercharger, and the 2nd stage is an aftermarket turbocharger system.
The net result of the two compressors is a compounding of pressure ratios. For example if the turbocharger waste-gate opening spring is set to a setting of 7psi of pressure above atmosphere (which is a pressure ratio of 1.5 given that 1 atmosphere is about 14.7 psig); and if the supercharger is mechanically geared to flow 50% more than the engine (for positive displacement roots style superchargers) at any rpm, thus having an identical 7psi boost setting or a pressure ratio of 1.5; then the resultant pressure ratio of the system combined is :
PR total = PR turbo * PR supercharger = a pressure ratio of 2.25
A pressure ratio of 2.25 is equivalent to 18.4 psi of boost (not 14psi expected by adding the two stages together).
So anyway, how does this relate to octane requirements ?
If the turbocharger is feeding the supercharger for example, and the turbocharger is ingesting fresh air at ambient air temperatures (T1), then:
1- The air exiting the turbocharger will be at a temperature T2, higher than the ambient air temperature (T1) by about 60-80*C depending on the exact turbocharger, and where we are on the turbocharger compressor and efficiency map.
2- The air entering the supercharger will enter at a temperature T2 ~=T1+60 and exit at a temperature T3 which is higher than T2 by about another 60-80*C depending on the exact specifications of the supercharger.
3- If we had an intercooler after the supercharger, then the air entering the intercooler will be at 120 to 160*C above ambient temperatures which is a lot of heat for the intercooler to attempt to shed in the short amount of time that the air passes through the intercooler core.
4- If we have no post supercharger intercooler (which is common on cars where the supercharger is packaged into the intake manifold of the car), then the air entering the engine will be at some 120 to 160*C above ambient.
5- This excessively heated air not only reduces power output (By about 1 horsepower for every 13*C) but it also increases the probability of the air fuel mixture automatically igniting in the motor pre-maturely before the spark plug has fired, and if this pre-mature ignition occurs early enough to catch the piston significantly far away from top dead center, then the battling flame front pushing the piston downwards, and the inertia of the system (and force of other firing cylinders rotating this piston via the crankshaft) pushing the piston upwards will cause extremely high pressures and a temperature rise on the surface of the piston ultimately damaging it and possibly damaging other parts of the motor as well.
For these reasons (pressure compounding, and combined temperature rise) sequential charging has seen very little application in the past. The use of a higher octane fuel by definition means that the air fuel mixture is more resilient to auto-ignition and detonation. Furthermore, in the event of a pre-mature ignition, the higher octane fuel creates a slower traveling flame front which gives the piston more time to travel upwards in the cylinder bore (Closer to top dead center) before meeting the flame front and this reduces the time that the piston surface is improperly pressurized and overheated reducing the possibility of catastrophic failure. Last but not least, the use a water / methanol injection mix includes two phase-change events:
1- The injected methanol changes from a liquid state to a vapor state at its boiling point of 65*C, i.e. as soon as it hits the compressed air mixture coming from the supercharger outlet. This phase change absorbs a lot of the heat out of the air and methanol mixture reducing inlet air temperatures even before the mixture reaches the combustion chamber and starts to get compressed. This temperature reduction goes a long way towards eliminating or highly reducing the possibility of detonation.
2- The injected water, changes from a liquid state to a vapor state at its boiling point of 100*C which depending on the availability of an intercooler in the system, my occur in the intake plumbing before reaching the combustion chamber, or may not occur until the mixture is ignited. Either way, when the temperature is high enough, the water mist injected in the air stream will flash vaporize into steam also absorbing a generous amount of the heat created in the combustion.
The availability of these two octane boosters makes it now possible for aftermarket performance part manufacturers to deliver safe and reliable sequential charging kits to the mass market.
One such kit which I ran across in an article from hot rod magazine was developed by hellion performance (http://www.hellionpowersystems.com) for the factory supercharged GT-500 mustang.
The kit supposedly produce up to 1000 horsepower at a boost level of 24 psi using two 61mm Turbonetics turbochargers.
To achieve 1000 hp requires around 1500 cfm of airflow at 24psi or 1500cfm at a pressure ratio of 2.63, or 750cfm @ 2.63pr per turbocharger.
Since most compressor maps for this size of turbocharger (61mm) peak out at around 600cfm @ 2.63 pr @ around 50% efficiency which is an extreme point on the map (i.e. the turbocharger is maxed out at this point). I’m going to say that I am confident that the kit is capable of supporting 800hp with a typical pair 61mm turbocharger, however 1000hp although dyno-proven, does not agree with what is published on most 61mm turbochargers. I’m not doubting the kit, I am stating that I don’t have a better reference for the specific turbocharger used in the kit.
Furthermore, feeding 1000hp from 8 injectors requires eight 750cc/min injectors by my estimate and this agrees with what is mentioned on Hot Rod magazine’s article of needing 75lbs/hour injectors (each lb/hour is roughly equivalent to 10.5cc/min) at a minimum or a total fuel deliver requirement of 900 liters per hour of fuel at a the fuel rail pressure which is typically around 45psi.
Looking at the flow capacity of the GS342 fuel pump supplied with the kit, which is 255lph @ 30psi, then using 3 fuel pumps gives us the capacity for 765lph which is about 2125 hp worth of fuel, so in that regard the kit is capable of supporting the power figure.
As you can see, it is possible to design such a complex system if the information (Turbocharger compressor map, turbocharger temperature map, supercharger compressor map, supercharger temperature map …etc) information were available before hand. What remains a mystery and an art of trial and failure, is how over-engineered is your engine, how much torque can it produce and still continue to survive, and how long can it continue to survive at elevated power levels. That is altogether a more exciting question to answer.
W.Baker
The first time I ever heard of twin charging (using both a turbocharger and a supercharger on the same motor) was probably back in year 2000. At that time I was very interested in performance for the Toyota Celica and naturally I also read a lot about its sister cars (that shared some of the same engines) such as the Camry and the MR2.
One of the most interesting aftermarket parts I ran across at the time was the HKS turbo kit for the 4AGZE powered 1st generation mr2. The 4agze (for those that are not familiar with Toyota engines) is a peppy 170 horsepower 1.6 liter engine powered by the Toyota SC-12 roots type supercharger. On this car Toyota used an electromagnetically clutched supercharger that could be disabled during low power requirements such as cruising, and engaged when the user demands it.
One of the most important parts of the HKS kit is the bypass valve. This valve was used to direct air from the supercharger to the engine at lower rpm/flow points. Once the rpm’s rise, and the engine starts to demand more air, and the turbocharger is fully spooled, the valve switches over gradually till the turbocharger alone is feeding the engine while the supercharger is completely bypassed. The twin-charged MR2′s were rumored to break the 300hp mark in some cases, depending on the final boost level and the supporting modifications, and this level of power for a 1.6 litre motor at the time was quiet astounding.
The theory behind this kind of system is to use a small positive displacement (roots style) supercharger. Supercharger performance efficiency is typically at its highest at lower engine and supercharger rpm’s (for example from idle to 4000 rpm’s). Above 4000 rpm’s the supercharger’s performance and efficiency starts to drop, the horsepower required to drive it starts to rise exponentially, and the air temperature coming out of the supercharger starts to rise dramatically limiting performance.
On the other hand, using a generously sized turbocharger will allow us to feed the engine efficiently with cooler air (than that from an overworked supercharger) and maintain high rpm performance. The problem with using a larger turbocharger is that a generously sized turbocharger typically doesn’t spool before 3000 to 4000 rpm’s giving us a limited power band and thus providing no performance boost at lower rpm’s.
The idea of twin charging is to use both a supercharger and a turbocharger to have each charger do what it does best, have the supercharger boost the motor for low end torque, and as it runs out of steam, the turbocharger comes online to carry us through to redline.
There are three aspects to these types of systems that make them prohibitive to most tuners:
1. Cost and complexity: Having a complete supercharger system as well as a complete turbocharger system on the same vehicle is a lot of money to spend and a lot of parts to deal with and diagnose in case something does go wrong.
2. The bypass valve used to bypass the supercharger (and yet hold in all the air pressure coming from the turbocharger) as well as being able to control this valve electrically or mechanically requires a custom made one off valve that isn’t quite available off the shelf. Although as I write this it seems possible to find a large sized dual chamber bypass valve plumbed to operate on the differential pressure between the turbo outlet and the supercharger outlet to switchover once the turbocharger pressure = the supercharger pressure + the tension of the bypass valve opening mechanism.
3. Since we are using two different types of chargers with two different efficiency maps, it can get very complicated to figure out how to tune the motor (especially with much simpler fuel injection systems that were used at the time) because the air density can vary dramatically at the same rpm point and pressure level depending on which charger is feeding air to the motor and at what proportion. This is also where the HKS turbo kit for the 4agze was at its weakest, namely at smoothing the transition point fueling between the supercharger to turbocharger switchover.
One of the things that has changed over the last 10 years is the availability (and proliferation of knowledge) about available alternative fuels or octane boosters. Two such options are:
1- E85 fuel which is comprised of 85% Ethanol which has an octane rating of about 100 to 105 octane vs the typical 87 to 93 octane pump gasoline.
2- Water / methanol injection systems that can be used either as supplemental fueling system (based on the methanol content which carries an octane rating of 110 octane or higher) or can be used for in cylinder cooling when the water vapor injected with the methanol transforms into steam inside the combustion chamber, thus extracting lots heat out of the combustion chamber, and thus slowing down the speed of travel of the combustion flame front simulating the effects similar to those of a higher octane gasoline.
With the availability of these octane increasing or octane simulating concoctions, it has become more accessible of recent for the performance enthusiast to build a different type of twin charger system that does not require a bypass valve.
In this type of system the supercharger outlet is routed to feed the turbocharger inlet or vice versa. Rather than either the supercharger or the turbocharger feeding the engine individually (in parallel operation) and switching between the two, we are now using a two stage compression system where one stage is the factory supercharger, and the 2nd stage is an aftermarket turbocharger system.
The net result of the two compressors is a compounding of pressure ratios. For example if the turbocharger waste-gate opening spring is set to a setting of 7psi of pressure above atmosphere (which is a pressure ratio of 1.5 given that 1 atmosphere is about 14.7 psig); and if the supercharger is mechanically geared to flow 50% more than the engine (for positive displacement roots style superchargers) at any rpm, thus having an identical 7psi boost setting or a pressure ratio of 1.5; then the resultant pressure ratio of the system combined is :
PR total = PR turbo * PR supercharger = a pressure ratio of 2.25
A pressure ratio of 2.25 is equivalent to 18.4 psi of boost (not 14psi expected by adding the two stages together).
So anyway, how does this relate to octane requirements ?
If the turbocharger is feeding the supercharger for example, and the turbocharger is ingesting fresh air at ambient air temperatures (T1), then:
1- The air exiting the turbocharger will be at a temperature T2, higher than the ambient air temperature (T1) by about 60-80*C depending on the exact turbocharger, and where we are on the turbocharger compressor and efficiency map.
2- The air entering the supercharger will enter at a temperature T2 ~=T1+60 and exit at a temperature T3 which is higher than T2 by about another 60-80*C depending on the exact specifications of the supercharger.
3- If we had an intercooler after the supercharger, then the air entering the intercooler will be at 120 to 160*C above ambient temperatures which is a lot of heat for the intercooler to attempt to shed in the short amount of time that the air passes through the intercooler core.
4- If we have no post supercharger intercooler (which is common on cars where the supercharger is packaged into the intake manifold of the car), then the air entering the engine will be at some 120 to 160*C above ambient.
5- This excessively heated air not only reduces power output (By about 1 horsepower for every 13*C) but it also increases the probability of the air fuel mixture automatically igniting in the motor pre-maturely before the spark plug has fired, and if this pre-mature ignition occurs early enough to catch the piston significantly far away from top dead center, then the battling flame front pushing the piston downwards, and the inertia of the system (and force of other firing cylinders rotating this piston via the crankshaft) pushing the piston upwards will cause extremely high pressures and a temperature rise on the surface of the piston ultimately damaging it and possibly damaging other parts of the motor as well.
For these reasons (pressure compounding, and combined temperature rise) sequential charging has seen very little application in the past. The use of a higher octane fuel by definition means that the air fuel mixture is more resilient to auto-ignition and detonation. Furthermore, in the event of a pre-mature ignition, the higher octane fuel creates a slower traveling flame front which gives the piston more time to travel upwards in the cylinder bore (Closer to top dead center) before meeting the flame front and this reduces the time that the piston surface is improperly pressurized and overheated reducing the possibility of catastrophic failure. Last but not least, the use a water / methanol injection mix includes two phase-change events:
1- The injected methanol changes from a liquid state to a vapor state at its boiling point of 65*C, i.e. as soon as it hits the compressed air mixture coming from the supercharger outlet. This phase change absorbs a lot of the heat out of the air and methanol mixture reducing inlet air temperatures even before the mixture reaches the combustion chamber and starts to get compressed. This temperature reduction goes a long way towards eliminating or highly reducing the possibility of detonation.
2- The injected water, changes from a liquid state to a vapor state at its boiling point of 100*C which depending on the availability of an intercooler in the system, my occur in the intake plumbing before reaching the combustion chamber, or may not occur until the mixture is ignited. Either way, when the temperature is high enough, the water mist injected in the air stream will flash vaporize into steam also absorbing a generous amount of the heat created in the combustion.
The availability of these two octane boosters makes it now possible for aftermarket performance part manufacturers to deliver safe and reliable sequential charging kits to the mass market.
One such kit which I ran across in an article from hot rod magazine was developed by hellion performance (http://www.hellionpowersystems.com) for the factory supercharged GT-500 mustang.
The kit supposedly produce up to 1000 horsepower at a boost level of 24 psi using two 61mm Turbonetics turbochargers.
To achieve 1000 hp requires around 1500 cfm of airflow at 24psi or 1500cfm at a pressure ratio of 2.63, or 750cfm @ 2.63pr per turbocharger.
Since most compressor maps for this size of turbocharger (61mm) peak out at around 600cfm @ 2.63 pr @ around 50% efficiency which is an extreme point on the map (i.e. the turbocharger is maxed out at this point). I’m going to say that I am confident that the kit is capable of supporting 800hp with a typical pair 61mm turbocharger, however 1000hp although dyno-proven, does not agree with what is published on most 61mm turbochargers. I’m not doubting the kit, I am stating that I don’t have a better reference for the specific turbocharger used in the kit.
Furthermore, feeding 1000hp from 8 injectors requires eight 750cc/min injectors by my estimate and this agrees with what is mentioned on Hot Rod magazine’s article of needing 75lbs/hour injectors (each lb/hour is roughly equivalent to 10.5cc/min) at a minimum or a total fuel deliver requirement of 900 liters per hour of fuel at a the fuel rail pressure which is typically around 45psi.
Looking at the flow capacity of the GS342 fuel pump supplied with the kit, which is 255lph @ 30psi, then using 3 fuel pumps gives us the capacity for 765lph which is about 2125 hp worth of fuel, so in that regard the kit is capable of supporting the power figure.
As you can see, it is possible to design such a complex system if the information (Turbocharger compressor map, turbocharger temperature map, supercharger compressor map, supercharger temperature map …etc) information were available before hand. What remains a mystery and an art of trial and failure, is how over-engineered is your engine, how much torque can it produce and still continue to survive, and how long can it continue to survive at elevated power levels. That is altogether a more exciting question to answer.
W.Baker
Posted in Uncategorized |
Tags: Camry, Hks Turbo Kit, Horsepower, Rpm, Supercharger, Toyota Celica, Turbocharger |
Comments Closed
Dirk Gibson asked:
As a Mini Cooper owner, I can confirm that everything you’ve heard about how fun it is to drive is absolutely true. The car handles like it is on rails, but also has a surprising amount of spunk given its size. This is due to the maxed out engine.
The Mini comes in various models ranging from the basic hard top known as the Mini Cooper to a convertible and a Clubman which tries to be a car for four people. Each comes with a sport version that has a more powerful engine. There is also a JCW Mini. The JCW stands for John Cooper Works. Cooper was a Formula One and rally car builder associated with the company in the 1960s.
Regardless of the model of Mini you have, it has an inline 4 cylinder 1.6 liter engine. Many people assume this engine is a BMW model since Beemer owns the Mini brand. The engine carries the BMW name, but it was a Toyota model in the early years of this decade and now is based on a Peugeot in the 2008 and forward models. The reason for this appears to be the simply fact BMW didn’t have much experience building tiny engines that punched out big power. Toyota and particularly Peugeot did.
The engine in the Mini Cooper is normally aspirated in the base models. The “S” versions come with a turbocharger. The models of the first half of the decade had a supercharger instead of a turbocharger. Regardless, this is a little engine that can. Although it is small, the forced air system pushes the horsepower on the “S” versions into the middle 170s with the JCW versions popping up over 200. For such a small, light car, that is a lot of power.
The title of this article references the “purring” engine. Any Mini owner knows full well this is a joke. Although the engine has a lot of punch, it sounds like it has been in a brawl with a bit Mercedes engine. The thing literally sounds like one of those old diesel Mercedes your grandmother drove. It clicks. It knocks. It basically makes an unholy racket when it is idling. I actually went back to the dealer and listened to other cars on the lot that prospective buyers were starting up to make sure my car didn’t have a problem. All of them make the racket and it is normal.
The Mini Cooper is not the fastest car on the road. A MazdaSpeed 3 will blow it away. The Mini is, however, plenty fast enough thanks to a little engine that sounds like diesel, but performs like puma.
As a Mini Cooper owner, I can confirm that everything you’ve heard about how fun it is to drive is absolutely true. The car handles like it is on rails, but also has a surprising amount of spunk given its size. This is due to the maxed out engine.
The Mini comes in various models ranging from the basic hard top known as the Mini Cooper to a convertible and a Clubman which tries to be a car for four people. Each comes with a sport version that has a more powerful engine. There is also a JCW Mini. The JCW stands for John Cooper Works. Cooper was a Formula One and rally car builder associated with the company in the 1960s.
Regardless of the model of Mini you have, it has an inline 4 cylinder 1.6 liter engine. Many people assume this engine is a BMW model since Beemer owns the Mini brand. The engine carries the BMW name, but it was a Toyota model in the early years of this decade and now is based on a Peugeot in the 2008 and forward models. The reason for this appears to be the simply fact BMW didn’t have much experience building tiny engines that punched out big power. Toyota and particularly Peugeot did.
The engine in the Mini Cooper is normally aspirated in the base models. The “S” versions come with a turbocharger. The models of the first half of the decade had a supercharger instead of a turbocharger. Regardless, this is a little engine that can. Although it is small, the forced air system pushes the horsepower on the “S” versions into the middle 170s with the JCW versions popping up over 200. For such a small, light car, that is a lot of power.
The title of this article references the “purring” engine. Any Mini owner knows full well this is a joke. Although the engine has a lot of punch, it sounds like it has been in a brawl with a bit Mercedes engine. The thing literally sounds like one of those old diesel Mercedes your grandmother drove. It clicks. It knocks. It basically makes an unholy racket when it is idling. I actually went back to the dealer and listened to other cars on the lot that prospective buyers were starting up to make sure my car didn’t have a problem. All of them make the racket and it is normal.
The Mini Cooper is not the fastest car on the road. A MazdaSpeed 3 will blow it away. The Mini is, however, plenty fast enough thanks to a little engine that sounds like diesel, but performs like puma.
Posted in Cars |
Tags: Beemer, Bmw Model, Bmw Name, Car Builder, Jcw Mini, Light Car, Mercedes Engine, Rally Car, Supercharger, Turbocharger |
Comments Closed
Haitham Alhumsi asked:
There comes a point in your power buildup where you may consider adding nitrous oxide injection to your supercharged car. This point typically coincides with reaching a level of performance that means increased investment and diminishing returns from your supercharger. For example, my car comes from the factory with a 5th generation Eaton MP45 supercharger. This supercharger is limited to about 230hp worth of flow rating and so no matter what I do with bolt-on upgrades on my engine, my peak horsepower will not exceed 230hp limit because that is the point at which the supercharger becomes the bottle neck in my system.
As we’ve talked about in previous articles there is still the option of porting the factory supercharger for a 10 to 15% gain in capacity (which in this case would be another 23 to 35 horsepower). There is also the option of retrofitting a larger supercharger such as the Eaton M62 to gain potential up to over 300hp depending on the final choice of a supercharger.
This modification path (porting or replacing the factory supercharger) can prove to be complex and costly, especially if the supercharger is integrated into the intake manifold (and possibly an air to water intercooler) as the case is with many factory supercharged cars.
A possible viable solution for this situation is to use nitrous oxide injection to supplement the power delivery when racing, and being satisfied with a reliable lower powered car when the nitrous is off and we’re not racing.
The reason why nitrous oxide (N2O) becomes a great power adder is twofold:
1- Nitrous is cheap as far as horsepower per dollar goes, and especially in the situations where we’re already supercharged and so will only be using it on the rare occasions when we do hit the track.
2- Nitrous oxide is a great ‘chiller’ as it comes out of the bottle at a temperature of negative 127*F and is capable of cooling the overall supercharged air charge mixture by over 100*F as reported by enthusiasts, this is an additional temperature reduction over the effects of whatever intercooler you have fitted. This in-fact makes nitrous a great proposition for cars that have already maxed out their superchargers, where the supercharger is running at peak rpms and producing very high outlet temperatures. The nitrous oxide injection can effectively boost the thermal efficiency of the supercharger when it is most stressed out and give us a nice, cool, and dense mixture.
3- Nitrous oxide fuel delivery is fairly straight forward to setup and to tune, especially on newer model cars with return-les fuel systems, or difficult to ***** computers that make it difficult to upgrade (and properly tune) a much larger supercharger setup. Nitrous oxide fuel delivery can be set-up totally independently from the OEM ECU and fuel system and thus makes nitrous a possible application for German cars with stubborn computers.
4- This is a racer technique… most cars seem to perform better during the winter months because the air is cooler, horsepower is elevated, and the tracks although cold, can be prepared for traction and will heat up enough during the night to allow for traction and to give people the ability to exploit the cold dense air to post their best times of the year. As the weather gets warmer, traction increases because the asphalt is warm and sticky, but horsepower is reduced due to warmer, less dense air. Typically racers find that their cars vary in their quarter mile performance by as much as a half a second between their summer tune and their winter tune, especially if you’re using a supercharger or turbocharger that compresses (and further heats) the incoming air.
The solution to on-track consistency, racers have found, is to combine the use of nitrous oxide (which is summer friendly) with forced induction (superchargers and turbochargers) which are winter friendly. In the summer time, the outside temperature is high, and so the nitrous bottle pressure is maintained at a high level above 1100 psi. This allows for a generous nitrous flow rate under the sustained pressure (even without a bottle heater) which gives great summer performance for nitrous assisted cars. While in the winter, the outside temperatures drop significantly, the nitrous in the bottle contracts and the bottle pressure drops, subsequently, the nitrous flow rate drops and nitrous assisted cars show worse performance in the winter times.
The complete opposite is true for supercharged cars that produce great horsepower in the winter from compressing cool dense air, and poor horsepower in the summer heat. When you combine these two power adders you get pretty flat and consistent horsepower production year round because the supercharger shines when the nitrous is weak, and the nitrous shines when the supercharger is weak, and thus together, they give consistent power deliver year round.
Pre-cautions:
Now we have to consider that nitrous oxide is an oxidizer and thus not only does it increase the amount of air and fuel combusting in the cylinder, but it also produces a faster moving flame front due to the oxidizer properties of the nitrous oxide. This means that additional timing retard, great octane fuel, and possibly colder spark plugs will be required to run spray on a supercharged car. Furthermore, because of its cooling effect, a 100hp shot on a supercharged Camaro can very easily put down OVER 120 rear wheel horsepower of additional power. This means that the ‘out of the box’ jetting of a nitrous kit may not be adequate on a supercharged car and you’d have to make sure to monitor and possibly increase the fuel jetting to match the final horsepower figure of your car). Last but not least, if you’re running a 500hp supercharged car with an additional 120hp of nitrous oxide injection, then you must make sure that your fuel delivery (fuel pump and fuel lines) are able to flow the total amount of fuel required to deliver 620hp.
Applications scenarios:
1- You have a car like mine, a 2005 C230 kompressor that comes with a 230hp limited Eaton MP45. ECU on the car is a Siemens ECU that very few people know how to tune, and the fuel system uses a return-less setup with an in-tank fuel pressure regulator. With this kind of setup all forms of dry nitrous injection are out of the question because we can neither compensate for fuel through flashing the factory ECU, nor can we elevate fuel pressure during the nitrous injection because the fuel pressure regulator is in-accessible….
Recommended kit:
A wet nitrous injection kit that injects both fuel and nitrous oxide from the injection nozzle.
Injection location:
After the supercharger, after the intercooler, and into the intake manifold of the car.
Maximum recommended injection:
25% of the original total power figure which corresponds to around a 50 hp shot of nitrous on our example.
Expected final horsepower:
60 to 65 wheel horsepower and possible about 130 ft-lbs of additional torque!
2- You have a car that has an accessible fuel pressure regulator, or an ECU that can be re-flashed for nitrous oxide or a ‘dual tune’ setup. In this case it is recommended to use a dry nitrous kit for two reasons:
First: Dry kits are safer on supercharged cars (as long as the fuel delivery through the injectors or raised fuel pressure is adequate) because they hold a reduced chance of intake backfires because the intake manifold is dry of fuel.
Second: Dry nitrous injection contains no fuel, and so we don’t need to worry about fuel falling out of suspension from the injected air. This means that we no longer have to spray the nitrous right before the intake manifold and we now have the option to move the point of injection much farther back. Spraying nitrous BEFORE the intercooler, right after the supercharger gives the nitrous stream more time and more contact with the compressed air coming out of the supercharger which results in more cooling and further increased horsepower.
Recommended kit:
A dry nitrous injection kit that injects only nitrous oxide from the injection nozzle.
Injection location:
After the supercharger, before or after the intercooler and not necessarily right at the intake manifold of the car.
Maximum recommended injection:
25% of the original total power figure which corresponds to around a 50 hp shot of nitrous.
Expected final horsepower:
70-75 wheel horsepower and possible about 130 ft-lbs of additional torque!
3- You have a car that has an accessible fuel pressure regulator, or an ECU that can flashed for nitrous oxide or a ‘dual tune’ setup. You also want to make as much horsepower as possible from your nitrous…
In this case it is recommended to use a dry nitrous kit injecting before the supercharger. As we mentioned in our articles on twin charging (combining turbochargers with superchargers for added performance), when two ‘chargers’ are chained in series where one charger feeds the next, then the two pressure ratios of the charger combine because the second charger compresses air that is already compressed by the first. For example two turbochargers set for a 1.5 pressure ratio (or 7 psi of boost), running in sequential mode will result in a final pressure ratio of 2.25 bar (or 18psi of boost) which is more than the ‘expected’ 14psi that is the sum of the two boost levels.
Similarly, injecting nitrous oxide before the supercharger, delivers already compressed air. This is true weather we are talking about nitrous being compressed because it has twice the oxygen concentration as normal air or we’re talking about the nitrous cooling and compressing the incoming air. The final amount of compression observed by the supercharger inlet will vary depending on the ratio of incoming air to the size of the nitrous shot, and can result in an increase in boost of between 0.5 to 2.5 psi!
This boost increase is in addition to the power increase of the nitrous oxide injection and so it can be an additional 5 to 25 hp.
Recommended kit:
A dry nitrous injection kit that injects only nitrous oxide from the injection nozzle.
Injection location:
Before the supercharger inlet.
Maximum recommended injection:
25% of the original total power figure which corresponds to around a 50 hp shot of nitrous.
Expected final horsepower:
75-100 wheel horsepower and possible about 160 ft-lbs of additional torque!
Things to avoid:
1- No matter where you setup the nitrous injection, make sure not to spray nitrous into your MAS air flow sensor or your intake air temperature sensor. These temperature dependant sensors, tell the ECU to advance the timing in colder conditions. As we mentioned earlier, nitrous is an oxidizer that increases the speed of travel of the combustion event and thus requires maintained (if not retarded) ignition timing compared to a supercharged only setup. Avoid spraying on these temperature sensitive sensors to prevent accidental timing advance from occurring.
2- Avoid spraying a wet kit (fuel) before your supercharger, as the wet fuel mist will damage the supercharger rotors and strip their coatings.
3- Make sure you check your air fuel ratio on the nitrous and don’t stick to the ‘out of the box’ air to fuel settings with the kit. For example an extra 2.5 psi in your intake may or may not be compensated by your stock ECU and so depending on how well the ECU reacts you will have to adjust the fuel jetting on the nitrous kit.
Wade
There comes a point in your power buildup where you may consider adding nitrous oxide injection to your supercharged car. This point typically coincides with reaching a level of performance that means increased investment and diminishing returns from your supercharger. For example, my car comes from the factory with a 5th generation Eaton MP45 supercharger. This supercharger is limited to about 230hp worth of flow rating and so no matter what I do with bolt-on upgrades on my engine, my peak horsepower will not exceed 230hp limit because that is the point at which the supercharger becomes the bottle neck in my system.
As we’ve talked about in previous articles there is still the option of porting the factory supercharger for a 10 to 15% gain in capacity (which in this case would be another 23 to 35 horsepower). There is also the option of retrofitting a larger supercharger such as the Eaton M62 to gain potential up to over 300hp depending on the final choice of a supercharger.
This modification path (porting or replacing the factory supercharger) can prove to be complex and costly, especially if the supercharger is integrated into the intake manifold (and possibly an air to water intercooler) as the case is with many factory supercharged cars.
A possible viable solution for this situation is to use nitrous oxide injection to supplement the power delivery when racing, and being satisfied with a reliable lower powered car when the nitrous is off and we’re not racing.
The reason why nitrous oxide (N2O) becomes a great power adder is twofold:
1- Nitrous is cheap as far as horsepower per dollar goes, and especially in the situations where we’re already supercharged and so will only be using it on the rare occasions when we do hit the track.
2- Nitrous oxide is a great ‘chiller’ as it comes out of the bottle at a temperature of negative 127*F and is capable of cooling the overall supercharged air charge mixture by over 100*F as reported by enthusiasts, this is an additional temperature reduction over the effects of whatever intercooler you have fitted. This in-fact makes nitrous a great proposition for cars that have already maxed out their superchargers, where the supercharger is running at peak rpms and producing very high outlet temperatures. The nitrous oxide injection can effectively boost the thermal efficiency of the supercharger when it is most stressed out and give us a nice, cool, and dense mixture.
3- Nitrous oxide fuel delivery is fairly straight forward to setup and to tune, especially on newer model cars with return-les fuel systems, or difficult to ***** computers that make it difficult to upgrade (and properly tune) a much larger supercharger setup. Nitrous oxide fuel delivery can be set-up totally independently from the OEM ECU and fuel system and thus makes nitrous a possible application for German cars with stubborn computers.
4- This is a racer technique… most cars seem to perform better during the winter months because the air is cooler, horsepower is elevated, and the tracks although cold, can be prepared for traction and will heat up enough during the night to allow for traction and to give people the ability to exploit the cold dense air to post their best times of the year. As the weather gets warmer, traction increases because the asphalt is warm and sticky, but horsepower is reduced due to warmer, less dense air. Typically racers find that their cars vary in their quarter mile performance by as much as a half a second between their summer tune and their winter tune, especially if you’re using a supercharger or turbocharger that compresses (and further heats) the incoming air.
The solution to on-track consistency, racers have found, is to combine the use of nitrous oxide (which is summer friendly) with forced induction (superchargers and turbochargers) which are winter friendly. In the summer time, the outside temperature is high, and so the nitrous bottle pressure is maintained at a high level above 1100 psi. This allows for a generous nitrous flow rate under the sustained pressure (even without a bottle heater) which gives great summer performance for nitrous assisted cars. While in the winter, the outside temperatures drop significantly, the nitrous in the bottle contracts and the bottle pressure drops, subsequently, the nitrous flow rate drops and nitrous assisted cars show worse performance in the winter times.
The complete opposite is true for supercharged cars that produce great horsepower in the winter from compressing cool dense air, and poor horsepower in the summer heat. When you combine these two power adders you get pretty flat and consistent horsepower production year round because the supercharger shines when the nitrous is weak, and the nitrous shines when the supercharger is weak, and thus together, they give consistent power deliver year round.
Pre-cautions:
Now we have to consider that nitrous oxide is an oxidizer and thus not only does it increase the amount of air and fuel combusting in the cylinder, but it also produces a faster moving flame front due to the oxidizer properties of the nitrous oxide. This means that additional timing retard, great octane fuel, and possibly colder spark plugs will be required to run spray on a supercharged car. Furthermore, because of its cooling effect, a 100hp shot on a supercharged Camaro can very easily put down OVER 120 rear wheel horsepower of additional power. This means that the ‘out of the box’ jetting of a nitrous kit may not be adequate on a supercharged car and you’d have to make sure to monitor and possibly increase the fuel jetting to match the final horsepower figure of your car). Last but not least, if you’re running a 500hp supercharged car with an additional 120hp of nitrous oxide injection, then you must make sure that your fuel delivery (fuel pump and fuel lines) are able to flow the total amount of fuel required to deliver 620hp.
Applications scenarios:
1- You have a car like mine, a 2005 C230 kompressor that comes with a 230hp limited Eaton MP45. ECU on the car is a Siemens ECU that very few people know how to tune, and the fuel system uses a return-less setup with an in-tank fuel pressure regulator. With this kind of setup all forms of dry nitrous injection are out of the question because we can neither compensate for fuel through flashing the factory ECU, nor can we elevate fuel pressure during the nitrous injection because the fuel pressure regulator is in-accessible….
Recommended kit:
A wet nitrous injection kit that injects both fuel and nitrous oxide from the injection nozzle.
Injection location:
After the supercharger, after the intercooler, and into the intake manifold of the car.
Maximum recommended injection:
25% of the original total power figure which corresponds to around a 50 hp shot of nitrous on our example.
Expected final horsepower:
60 to 65 wheel horsepower and possible about 130 ft-lbs of additional torque!
2- You have a car that has an accessible fuel pressure regulator, or an ECU that can be re-flashed for nitrous oxide or a ‘dual tune’ setup. In this case it is recommended to use a dry nitrous kit for two reasons:
First: Dry kits are safer on supercharged cars (as long as the fuel delivery through the injectors or raised fuel pressure is adequate) because they hold a reduced chance of intake backfires because the intake manifold is dry of fuel.
Second: Dry nitrous injection contains no fuel, and so we don’t need to worry about fuel falling out of suspension from the injected air. This means that we no longer have to spray the nitrous right before the intake manifold and we now have the option to move the point of injection much farther back. Spraying nitrous BEFORE the intercooler, right after the supercharger gives the nitrous stream more time and more contact with the compressed air coming out of the supercharger which results in more cooling and further increased horsepower.
Recommended kit:
A dry nitrous injection kit that injects only nitrous oxide from the injection nozzle.
Injection location:
After the supercharger, before or after the intercooler and not necessarily right at the intake manifold of the car.
Maximum recommended injection:
25% of the original total power figure which corresponds to around a 50 hp shot of nitrous.
Expected final horsepower:
70-75 wheel horsepower and possible about 130 ft-lbs of additional torque!
3- You have a car that has an accessible fuel pressure regulator, or an ECU that can flashed for nitrous oxide or a ‘dual tune’ setup. You also want to make as much horsepower as possible from your nitrous…
In this case it is recommended to use a dry nitrous kit injecting before the supercharger. As we mentioned in our articles on twin charging (combining turbochargers with superchargers for added performance), when two ‘chargers’ are chained in series where one charger feeds the next, then the two pressure ratios of the charger combine because the second charger compresses air that is already compressed by the first. For example two turbochargers set for a 1.5 pressure ratio (or 7 psi of boost), running in sequential mode will result in a final pressure ratio of 2.25 bar (or 18psi of boost) which is more than the ‘expected’ 14psi that is the sum of the two boost levels.
Similarly, injecting nitrous oxide before the supercharger, delivers already compressed air. This is true weather we are talking about nitrous being compressed because it has twice the oxygen concentration as normal air or we’re talking about the nitrous cooling and compressing the incoming air. The final amount of compression observed by the supercharger inlet will vary depending on the ratio of incoming air to the size of the nitrous shot, and can result in an increase in boost of between 0.5 to 2.5 psi!
This boost increase is in addition to the power increase of the nitrous oxide injection and so it can be an additional 5 to 25 hp.
Recommended kit:
A dry nitrous injection kit that injects only nitrous oxide from the injection nozzle.
Injection location:
Before the supercharger inlet.
Maximum recommended injection:
25% of the original total power figure which corresponds to around a 50 hp shot of nitrous.
Expected final horsepower:
75-100 wheel horsepower and possible about 160 ft-lbs of additional torque!
Things to avoid:
1- No matter where you setup the nitrous injection, make sure not to spray nitrous into your MAS air flow sensor or your intake air temperature sensor. These temperature dependant sensors, tell the ECU to advance the timing in colder conditions. As we mentioned earlier, nitrous is an oxidizer that increases the speed of travel of the combustion event and thus requires maintained (if not retarded) ignition timing compared to a supercharged only setup. Avoid spraying on these temperature sensitive sensors to prevent accidental timing advance from occurring.
2- Avoid spraying a wet kit (fuel) before your supercharger, as the wet fuel mist will damage the supercharger rotors and strip their coatings.
3- Make sure you check your air fuel ratio on the nitrous and don’t stick to the ‘out of the box’ air to fuel settings with the kit. For example an extra 2.5 psi in your intake may or may not be compensated by your stock ECU and so depending on how well the ECU reacts you will have to adjust the fuel jetting on the nitrous kit.
Wade
Posted in Cars |
Tags: Air To Water Intercooler, Intake Manifold, Retrofitting, Supercharged Car, Supercharger |
Comments Closed
Redline Motive asked:
Why has supercharging become so popular?
There are a number of reasons. First, an efficient supercharger system can produce yesterday’s musclecar performance using today’s low-octane gasoline, with exceptional reliability and minimal impact upon fuel economy. Second, superchargers have developed to the point that they are easy to install and simple to maintain, especially when compared to pulling, rebuilding and fine-tuning an engine. Finally, unlike nitrous oxide, which requires frequent repurchase of fuel, once a supercharger is installed there is no more expense or hassle associated with performance. In short, supercharging delivers exceptional performance with little of the hassles traditionally associated with high performance. Centrifugal supercharging is the only way to make a reliable 500, 600, 700+ horsepower on otherwise stock, daily driven V-8′s.
How does supercharging increase engine performance?
Superchargers achieve performance gains by increasing the density of the air/fuel charge within the combustion chambers of an engine. This increase in density is achieved by forcing additional amounts of air (beyond the amount of air that normal atmospheric pressure would force into the engine) at the lowest temperature possible. CFM measures the volume of air that an engine is flowing, while MAF (mass air flow) also factors in the temperature of the air charge, since a cooler charge is more dense and therefore more powerful. So in more technical terms, supercharging increases both the volumetric efficiency of the engine and the mass air flow through the engine to produce gains in both horsepower and torque.
How much horsepower will a supercharger add to my engine?
Although some manufacturers claim a specific horsepower increase, superchargers actually add horsepower as a percentage gain (percentage of an atmosphere). Assuming an engine with a compression ratio of around 9:1 running pump gas,if a supercharger gives your engine 14.7 psi of boost (another atmosphere) that will essentially double the output of your engine, everything else being equal. After adjusting for thermal and mechanical energy transfer, if an efficient centrifugal supercharger is generating 7.5 psi (approx. 1/2 an atmosphere), you will see around a 35-40% gain in horsepower and torque at your non-supercharged maximum horsepower rpm. If detonation forces you to use an ignition/timing retard system, you will of course see less of a gain because backing off several degrees of timing will greatly reduce an engine’s power output. At higher boost levels, the heat generated by compressing air will produce diminishing returns as the boost is increased, although the use of intercooling or racing fuel can avoid this scenario of diminishing returns. Assuming the use of intercooling to run higher boost levels while maintaining reliability, a 100% increase can generally be achieved at around 17 psi on an engine with 9:1 compression running pump gas.
What type of fuel do I need with a supercharged automotive or truck engine?
The primary issues that determine the type of fuel needed are whether the engine is fuel-injected or carbureted, the compression ratio of the engine, and whether or not the supercharger system is intercooled.
For Intercooled ProCharger EFI/TPI applications with compression ratios less than 9.5:1, boost levels of 14-17 psi can be safely run with full timing on pump gas, and will produce horsepower gains of 75-100% (depending upon the boost level and the motor specifications). For 9.5:1 EFI/TPI applications running without an intercooler, boost levels above 5 psi will require the use of ignition/timing retard on pump gas, and will produce horsepower gains of 35-45%. Boost levels above 12 psi should generally be avoided even with racing fuel on a 9.5:1 motor. Of course, lower compression motors will be able to run more boost, and higher compression motors should run less boost, everything else being equal.
For carbureted motors, the rules are slightly different. Carburetors deliver the vast majority of fuel in a liquid state, and as this raw fuel atomizes from liquid to gas, a chemical state change actually occurs. Due to this endothermic reaction, which draws heat and cools the incoming air, a carbureted motor can safely handle more boost than a comparable EFI/TPI motor. For carbureted engines with compression ratios of 9:1 or less and boost levels in the 8-14 psi range, pump gasoline works very well. Compression ratios of 10:1 and higher require lower boost levels, higher octane fuel, intercooling, or some combination of the above. Compression ratios in the 7or 8:1 range can usually handle 12-20 psi on pump gasoline.
What is detonation, and how can it be controlled?
Detonation, or engine knock, occurs simply when fuel pre-ignites before the piston reaches scheduled spark ignition. This means that a powerful explosion is trying to expand a cylinder chamber that is shrinking in size, attempting to reverse the direction of the piston and the engine. When detonation occurs, the internal pneumatic forces can actually exceed 10x the normal forces acting upon a properly operating high performance engine. Detonation is generally caused by excessive heat, excessive cylinder pressure, improper ignition timing, inadequate fuel octane or a combination of these. Of the previous, excessive heat is usually the culprit. As an engine is modified to generate more power, additional heat is produced. Today’s pump gas will only tolerate a finite amount of heat before it pre-ignites and causes detonation. Although forced induction engines usually produce far less heat than comparable naturally aspirated high compression engines, the cylinder temperatures in intercooled engines are radically cooler yet. It is rarely boost that causes detonation, just unnecessary heat. An intercooler is such a natural solution for forced induction, that in almost every sophisticated application, intercooling is part of the package.
For engines that are experiencing detonation problems, the primary options are the use of ignition/timing retard systems, higher octane fuel, or intercooling. While ignition retard systems can be helpful in certain situations, they can also greatly reduce the horsepower output of an engine, as any reduction in timing will reduce horsepower. And while a reduction in timing can save a motor from detonation, the excessive heat which was causing the detonation is still present. Intercooling, on the other hand, actually removes the heat which causes detonation, and allows higher boost levels to be safely run with full timing on pump gas. This produces the maximum benefit in terms of both horsepower gains and engine protection, without any additional maintenance or hassle.
How will a supercharger affect my fuel economy?
Although roots superchargers have significant parasitic load and do dramatically decrease fuel economy, centrifugal superchargers will yield approximately the same fuel economy as normally aspirated engines, under normal throttle conditions. When racing, however, fuel enconomy will decrease given the supercharged engine’s ability to consume additional fuel and produce additional horsepower.
Will a supercharger shorten the life of my engine or drivetrain?
That is a very subjective question, as the manner in which an automobile is driven directly affects engine life. Assuming a properly tuned system, proper oil change and engine maintenance, and similar driving, supercharging generally will not shorten the life of an engine, just as is the case with OEM turbocharging (with proper cooldown for turbochargers. A cooldown period after driving is not necessary with supercharging). This is especially true of centrifugal supercharging, which generates boost in line with engine rpm, unlike roots and twin ***** blowers, whose low rpm boost can place additional strain on the engine and drive train.
Superchargers can be used with automatic or manual transmissions and will not increase transmission wear under normal driving. When racing, however, the additional torque provided by supercharging will place additional load on the transmission, especially when increased traction is present, such as with slicks. This impact is minimized when the boost increases with engine rpm, as is the case with centrifugal supercharging and turbocharging.
What is the difference between Supercharging and Turbocharging?
A supercharger is a mechanically driven air pump that is connected directly to the engine crankshaft via the serpentine belt. A turbocharger is driven by the flow of exhaust gas which is generated as part of the engine combustion cycle.
Why choose Supercharging over Turbocharging?
Because turbochargers depend on the energy in the exhaust gas stream to spool up and generate boost pressure, there is often a delay in the response of the engine at lower engine speeds where exhaust energy is lower. This delay is often referred to as “Turbo Lag”. On the other hand, a supercharger is directly driven by the crankshaft of the engine, and there is no delay in engine response at lower engine speeds. This allows supercharged engines to have instant throttle response and better vehicle driveability.
If more air is pumped into the engine, then more fuel must be used also…Doesn’t this mean less fuel economy?
If a supercharged 3.8L V6 is compared to a naturally aspirated 3.8L V6, the supercharged V6 does use slightly more fuel. However, the power and performance of the supercharged V6 is comparable to a larger V8 which uses much more fuel to achieve the same performance.
Does the Supercharger provide boost at all times?
No. Under cruising conditions, the compressed air from the supercharger is bypassed, and is recirculated in the supercharger, improving fuel efficiency. Under acceleration, the bypass is closed, and the “boosted” air is sent into the engine to provide increased response and power.
How reliable are supercharged engines?
General Motors has been offering a supercharged version of the 3800 V6 engine since 1991. The Supercharged 3800 Series II engine has one of the best warranty ratings amongst all of General Motors powertrain offerings. Along with GM, other automakers like Jaguar, Mercedes-Benz, Nissan, BMW-Mini, and Ford all have used superchargers as an effective and reliable alternative to larger, less fuel efficient powertrains on various cars and trucks.
George
Why has supercharging become so popular?
There are a number of reasons. First, an efficient supercharger system can produce yesterday’s musclecar performance using today’s low-octane gasoline, with exceptional reliability and minimal impact upon fuel economy. Second, superchargers have developed to the point that they are easy to install and simple to maintain, especially when compared to pulling, rebuilding and fine-tuning an engine. Finally, unlike nitrous oxide, which requires frequent repurchase of fuel, once a supercharger is installed there is no more expense or hassle associated with performance. In short, supercharging delivers exceptional performance with little of the hassles traditionally associated with high performance. Centrifugal supercharging is the only way to make a reliable 500, 600, 700+ horsepower on otherwise stock, daily driven V-8′s.
How does supercharging increase engine performance?
Superchargers achieve performance gains by increasing the density of the air/fuel charge within the combustion chambers of an engine. This increase in density is achieved by forcing additional amounts of air (beyond the amount of air that normal atmospheric pressure would force into the engine) at the lowest temperature possible. CFM measures the volume of air that an engine is flowing, while MAF (mass air flow) also factors in the temperature of the air charge, since a cooler charge is more dense and therefore more powerful. So in more technical terms, supercharging increases both the volumetric efficiency of the engine and the mass air flow through the engine to produce gains in both horsepower and torque.
How much horsepower will a supercharger add to my engine?
Although some manufacturers claim a specific horsepower increase, superchargers actually add horsepower as a percentage gain (percentage of an atmosphere). Assuming an engine with a compression ratio of around 9:1 running pump gas,if a supercharger gives your engine 14.7 psi of boost (another atmosphere) that will essentially double the output of your engine, everything else being equal. After adjusting for thermal and mechanical energy transfer, if an efficient centrifugal supercharger is generating 7.5 psi (approx. 1/2 an atmosphere), you will see around a 35-40% gain in horsepower and torque at your non-supercharged maximum horsepower rpm. If detonation forces you to use an ignition/timing retard system, you will of course see less of a gain because backing off several degrees of timing will greatly reduce an engine’s power output. At higher boost levels, the heat generated by compressing air will produce diminishing returns as the boost is increased, although the use of intercooling or racing fuel can avoid this scenario of diminishing returns. Assuming the use of intercooling to run higher boost levels while maintaining reliability, a 100% increase can generally be achieved at around 17 psi on an engine with 9:1 compression running pump gas.
What type of fuel do I need with a supercharged automotive or truck engine?
The primary issues that determine the type of fuel needed are whether the engine is fuel-injected or carbureted, the compression ratio of the engine, and whether or not the supercharger system is intercooled.
For Intercooled ProCharger EFI/TPI applications with compression ratios less than 9.5:1, boost levels of 14-17 psi can be safely run with full timing on pump gas, and will produce horsepower gains of 75-100% (depending upon the boost level and the motor specifications). For 9.5:1 EFI/TPI applications running without an intercooler, boost levels above 5 psi will require the use of ignition/timing retard on pump gas, and will produce horsepower gains of 35-45%. Boost levels above 12 psi should generally be avoided even with racing fuel on a 9.5:1 motor. Of course, lower compression motors will be able to run more boost, and higher compression motors should run less boost, everything else being equal.
For carbureted motors, the rules are slightly different. Carburetors deliver the vast majority of fuel in a liquid state, and as this raw fuel atomizes from liquid to gas, a chemical state change actually occurs. Due to this endothermic reaction, which draws heat and cools the incoming air, a carbureted motor can safely handle more boost than a comparable EFI/TPI motor. For carbureted engines with compression ratios of 9:1 or less and boost levels in the 8-14 psi range, pump gasoline works very well. Compression ratios of 10:1 and higher require lower boost levels, higher octane fuel, intercooling, or some combination of the above. Compression ratios in the 7or 8:1 range can usually handle 12-20 psi on pump gasoline.
What is detonation, and how can it be controlled?
Detonation, or engine knock, occurs simply when fuel pre-ignites before the piston reaches scheduled spark ignition. This means that a powerful explosion is trying to expand a cylinder chamber that is shrinking in size, attempting to reverse the direction of the piston and the engine. When detonation occurs, the internal pneumatic forces can actually exceed 10x the normal forces acting upon a properly operating high performance engine. Detonation is generally caused by excessive heat, excessive cylinder pressure, improper ignition timing, inadequate fuel octane or a combination of these. Of the previous, excessive heat is usually the culprit. As an engine is modified to generate more power, additional heat is produced. Today’s pump gas will only tolerate a finite amount of heat before it pre-ignites and causes detonation. Although forced induction engines usually produce far less heat than comparable naturally aspirated high compression engines, the cylinder temperatures in intercooled engines are radically cooler yet. It is rarely boost that causes detonation, just unnecessary heat. An intercooler is such a natural solution for forced induction, that in almost every sophisticated application, intercooling is part of the package.
For engines that are experiencing detonation problems, the primary options are the use of ignition/timing retard systems, higher octane fuel, or intercooling. While ignition retard systems can be helpful in certain situations, they can also greatly reduce the horsepower output of an engine, as any reduction in timing will reduce horsepower. And while a reduction in timing can save a motor from detonation, the excessive heat which was causing the detonation is still present. Intercooling, on the other hand, actually removes the heat which causes detonation, and allows higher boost levels to be safely run with full timing on pump gas. This produces the maximum benefit in terms of both horsepower gains and engine protection, without any additional maintenance or hassle.
How will a supercharger affect my fuel economy?
Although roots superchargers have significant parasitic load and do dramatically decrease fuel economy, centrifugal superchargers will yield approximately the same fuel economy as normally aspirated engines, under normal throttle conditions. When racing, however, fuel enconomy will decrease given the supercharged engine’s ability to consume additional fuel and produce additional horsepower.
Will a supercharger shorten the life of my engine or drivetrain?
That is a very subjective question, as the manner in which an automobile is driven directly affects engine life. Assuming a properly tuned system, proper oil change and engine maintenance, and similar driving, supercharging generally will not shorten the life of an engine, just as is the case with OEM turbocharging (with proper cooldown for turbochargers. A cooldown period after driving is not necessary with supercharging). This is especially true of centrifugal supercharging, which generates boost in line with engine rpm, unlike roots and twin ***** blowers, whose low rpm boost can place additional strain on the engine and drive train.
Superchargers can be used with automatic or manual transmissions and will not increase transmission wear under normal driving. When racing, however, the additional torque provided by supercharging will place additional load on the transmission, especially when increased traction is present, such as with slicks. This impact is minimized when the boost increases with engine rpm, as is the case with centrifugal supercharging and turbocharging.
What is the difference between Supercharging and Turbocharging?
A supercharger is a mechanically driven air pump that is connected directly to the engine crankshaft via the serpentine belt. A turbocharger is driven by the flow of exhaust gas which is generated as part of the engine combustion cycle.
Why choose Supercharging over Turbocharging?
Because turbochargers depend on the energy in the exhaust gas stream to spool up and generate boost pressure, there is often a delay in the response of the engine at lower engine speeds where exhaust energy is lower. This delay is often referred to as “Turbo Lag”. On the other hand, a supercharger is directly driven by the crankshaft of the engine, and there is no delay in engine response at lower engine speeds. This allows supercharged engines to have instant throttle response and better vehicle driveability.
If more air is pumped into the engine, then more fuel must be used also…Doesn’t this mean less fuel economy?
If a supercharged 3.8L V6 is compared to a naturally aspirated 3.8L V6, the supercharged V6 does use slightly more fuel. However, the power and performance of the supercharged V6 is comparable to a larger V8 which uses much more fuel to achieve the same performance.
Does the Supercharger provide boost at all times?
No. Under cruising conditions, the compressed air from the supercharger is bypassed, and is recirculated in the supercharger, improving fuel efficiency. Under acceleration, the bypass is closed, and the “boosted” air is sent into the engine to provide increased response and power.
How reliable are supercharged engines?
General Motors has been offering a supercharged version of the 3800 V6 engine since 1991. The Supercharged 3800 Series II engine has one of the best warranty ratings amongst all of General Motors powertrain offerings. Along with GM, other automakers like Jaguar, Mercedes-Benz, Nissan, BMW-Mini, and Ford all have used superchargers as an effective and reliable alternative to larger, less fuel efficient powertrains on various cars and trucks.
George
Posted in Uncategorized |
Tags: Engine Performance, Fuel Economy, Mass Air Flow, Musclecar, Octane Gasoline, Supercharger, Supercharger System, Superchargers |
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Bond Mejeh asked:
Supercharging and turbo-charging your engine will get you the same thing: more horsepower. Both work by increasing the amount of air that goes into the combustion chamber, resulting in a more powerful explosion. However, they both do it in very different ways.
A supercharger works by taking power from the engine via a belt/pulley system. The belt turns an impeller inside the supercharger that forces more air into the combustion chamber. The benefits of having a supercharger, is that it’s very straightforward to use, and the power is there whenever you need it. Also, a cool feature about it is that it doesn’t require special cooling or maintenance. It’s easily more reliable than turbochargers.
A supercharger also provides a smooth boost throughout the entire power-band, which results in more predictable handling and power at low, as well as high RPM’s. The downside of supercharging is that it uses a small amount of power from the engine all of the time (because of the pulley). Ironically, the more power the supercharger produces, the more power it pulls from the system. But the net result of having a supercharger would most likely turnout better than not owning a supercharger at all.
A turbo charger works much like a supercharger, where it forces more air into the combustion chamber. However, instead of being driven by a pulley/belt combo attached to the engine, the impeller is spun by exhaust gasses from the engine. When the engine is at rest, the turbo charger impeller is idling, because there is little pressure in the exhaust that is released from the engine. As the engine is revved, more exhaust pressure hits the turbo charger’s impeller causing it to turn, which puts more air in the combustion chamber, which also increases the exhaust pressure by hitting the turbo impeller. Hopefully you can see where this is going at this point. The faster you go the more power the turbocharger produces.
The benefits of having this type of system, is having a lot of power being produced with no extra effort on the engine’s part. You can also increase the air density by adding intercoolers, which cools the air before the turbo gets put into the combustion chamber that allows an even greater increase in power. Another great aspect of owning a system like this is the ability to change the amount of boost available. With some models this can even be done while driving, allowing you to fine-tune the power you need.
However the big con of the turbo charger is the uneven power-band. At low RPM’s the engine is not producing enough exhaust pressure for the turbo charger to add power. This is known as turbo lag. Once it gets going though, it’s a very massive boost. So massive, in fact, that a poorly, setup turbo charger can be dangerous: the sudden and dramatic increase in power can cause the handling characteristics of the car to change. This was especially true of the older Porsche 911 Turbos, which had a habit of swinging the back-end out if you weren’t aware when the turbo boost hit. The other con of the turbo charger is its maintenance. There are more moving parts than in a supercharger, and some models require cool down time after heavy use before the engine can be shut off.
Superchargers are better used for the daily driver who wants a little more power in their engine without sacrificing the reliability or worrying about sudden amounts of power causing a spinout. In fact, there have been mini-vans that have come standard with superchargers, attesting to its same power. Turbo chargers are better used in sports cars, whose handling can accommodate the sudden change in power, where whose drivers are willing to sacrifice some reliability for a large increase in speed.
H Pittman
Supercharging and turbo-charging your engine will get you the same thing: more horsepower. Both work by increasing the amount of air that goes into the combustion chamber, resulting in a more powerful explosion. However, they both do it in very different ways.
A supercharger works by taking power from the engine via a belt/pulley system. The belt turns an impeller inside the supercharger that forces more air into the combustion chamber. The benefits of having a supercharger, is that it’s very straightforward to use, and the power is there whenever you need it. Also, a cool feature about it is that it doesn’t require special cooling or maintenance. It’s easily more reliable than turbochargers.
A supercharger also provides a smooth boost throughout the entire power-band, which results in more predictable handling and power at low, as well as high RPM’s. The downside of supercharging is that it uses a small amount of power from the engine all of the time (because of the pulley). Ironically, the more power the supercharger produces, the more power it pulls from the system. But the net result of having a supercharger would most likely turnout better than not owning a supercharger at all.
A turbo charger works much like a supercharger, where it forces more air into the combustion chamber. However, instead of being driven by a pulley/belt combo attached to the engine, the impeller is spun by exhaust gasses from the engine. When the engine is at rest, the turbo charger impeller is idling, because there is little pressure in the exhaust that is released from the engine. As the engine is revved, more exhaust pressure hits the turbo charger’s impeller causing it to turn, which puts more air in the combustion chamber, which also increases the exhaust pressure by hitting the turbo impeller. Hopefully you can see where this is going at this point. The faster you go the more power the turbocharger produces.
The benefits of having this type of system, is having a lot of power being produced with no extra effort on the engine’s part. You can also increase the air density by adding intercoolers, which cools the air before the turbo gets put into the combustion chamber that allows an even greater increase in power. Another great aspect of owning a system like this is the ability to change the amount of boost available. With some models this can even be done while driving, allowing you to fine-tune the power you need.
However the big con of the turbo charger is the uneven power-band. At low RPM’s the engine is not producing enough exhaust pressure for the turbo charger to add power. This is known as turbo lag. Once it gets going though, it’s a very massive boost. So massive, in fact, that a poorly, setup turbo charger can be dangerous: the sudden and dramatic increase in power can cause the handling characteristics of the car to change. This was especially true of the older Porsche 911 Turbos, which had a habit of swinging the back-end out if you weren’t aware when the turbo boost hit. The other con of the turbo charger is its maintenance. There are more moving parts than in a supercharger, and some models require cool down time after heavy use before the engine can be shut off.
Superchargers are better used for the daily driver who wants a little more power in their engine without sacrificing the reliability or worrying about sudden amounts of power causing a spinout. In fact, there have been mini-vans that have come standard with superchargers, attesting to its same power. Turbo chargers are better used in sports cars, whose handling can accommodate the sudden change in power, where whose drivers are willing to sacrifice some reliability for a large increase in speed.
H Pittman
Posted in Cars |
Tags: Belt Pulley, Exhaust Gasses, Exhaust Pressure, Horsepower, Impeller, Rpm, Supercharger, Turbo Charger, Turbocharger |
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Leaftech asked:
When you are looking to add that extra boost of power to your engine, whether it’s a muscle car or a tractor, you want to make sure that you explore all of the alternatives. Both turbochargers and superchargers have their advocates, but let’s focus on turbochargers and the advantages they have over superchargers.
What is a charger?
Both superchargers and turbochargers add extra horse power to an engine through the compression of air in the cylinder. Compressed air is forced into the engine, and this leaves room for more gas to explode in the cylinder, adding power to the engine. The difference between superchargers and turbochargers is that superchargers are powered by a belt driven by the engine itself, while turbochargers use exhaust gases to power a turbine wheel which supplies the boost.
The Advantages of a Turbocharger
Waste not, want not. Because turbochargers are driven by exhaust gases, they actually using emissions produced by the engine that would otherwise just go to waste in the atmosphere.
Engine wear. Superchargers depend on the engine to produce the power they need to add the extra boost, but turbochargers are strictly exhaust driven. The extra boost that a turbocharger provides is therefore calculated without any loss to drive the charger itself; superchargers use some of the boost they provide just to run themselves.
Efficiency. The turbine wheel and a shaft connecting it to the engine are all the hardware that a turbocharger uses. A supercharger, on the other hand, needs pulleys, belts, and gears to run. The amount of friction created by this extra material and the added weight may make a difference in performance.
More Power? A turbocharger will produce more power at lower RPMs than a supercharger. A regulator built inside the charger opens the waste gate, which gets rid of any extra pressure and enhances the performance. The waste gate typically has opened at between 2000 and 2500 RPMs. Improvements are also creating larger waste gates. In any event, turbochargers will give greater boost to the engine on paper, although there is traditionally concern about lag.
One of the last factors to consider in your decision is cost. Turbochargers cost less than superchargers, and they are also easier and less expensive to repair due to simpler engineering. Continued advancements in turbocharger technology have addressed concerns such as throttle performance due to lag, making the turbocharger the better performer all around.
When you are looking to add that extra boost of power to your engine, whether it’s a muscle car or a tractor, you want to make sure that you explore all of the alternatives. Both turbochargers and superchargers have their advocates, but let’s focus on turbochargers and the advantages they have over superchargers.
What is a charger?
Both superchargers and turbochargers add extra horse power to an engine through the compression of air in the cylinder. Compressed air is forced into the engine, and this leaves room for more gas to explode in the cylinder, adding power to the engine. The difference between superchargers and turbochargers is that superchargers are powered by a belt driven by the engine itself, while turbochargers use exhaust gases to power a turbine wheel which supplies the boost.
The Advantages of a Turbocharger
Waste not, want not. Because turbochargers are driven by exhaust gases, they actually using emissions produced by the engine that would otherwise just go to waste in the atmosphere.
Engine wear. Superchargers depend on the engine to produce the power they need to add the extra boost, but turbochargers are strictly exhaust driven. The extra boost that a turbocharger provides is therefore calculated without any loss to drive the charger itself; superchargers use some of the boost they provide just to run themselves.
Efficiency. The turbine wheel and a shaft connecting it to the engine are all the hardware that a turbocharger uses. A supercharger, on the other hand, needs pulleys, belts, and gears to run. The amount of friction created by this extra material and the added weight may make a difference in performance.
More Power? A turbocharger will produce more power at lower RPMs than a supercharger. A regulator built inside the charger opens the waste gate, which gets rid of any extra pressure and enhances the performance. The waste gate typically has opened at between 2000 and 2500 RPMs. Improvements are also creating larger waste gates. In any event, turbochargers will give greater boost to the engine on paper, although there is traditionally concern about lag.
One of the last factors to consider in your decision is cost. Turbochargers cost less than superchargers, and they are also easier and less expensive to repair due to simpler engineering. Continued advancements in turbocharger technology have addressed concerns such as throttle performance due to lag, making the turbocharger the better performer all around.
Posted in Uncategorized |
Tags: Exhaust Gases, Gears, Muscle Car, Supercharger, Turbine Wheel, Turbocharger, Turbochargers, Waste Gate |
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