Garrett Turbo

Kenneth S asked:


ive been looking for a replacement turbo for my sisters car for a long time. i want to replace it because it leaks really bad. she goes through a quart of oil about once a month. the car still runs surprisingly but i don’t want her driving it like that. i want to say those b230f engines run between 14-17 psi of boost. the engine is a 2.3L L4 engine. those engines run really well when they work correctly. ive been looking at the garrett turbo’s. what would be a good turbo to install that would give it a little more kick. ide like to see around 240+ hp. it was stock at 165hp and 195 torque. boost kicked in around 2000 rpm. has anyone done this before. im lost when it comes to picking a turbo.

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RJ Performance asked:




A turbocharger is defined as a fuel-driven turbine. Its main function is to compress the air which in turn increases the power and the engine torque. Air compressing and density increasing heed more amounts of air and more amounts of fuel within the engine. All of these things placed together equal to a more powerful, speedier turbine. Air density increase simply means that you harvest more oxygen per burn. The amount of energy that results will help drives the pistons that will move forth the air that has been compressed.

Many vehicles come equipped with twin turbo engines. A twin turbo engine setup means that the engine is running two turbo chargers to help deal with the compression. Below we will go into detail on how to decipher between the two types.

Twin Turbo:

Twin Turbo help to produce faster power utilizing 4-cylinders each for the spooling of the turbo charger. With this setup, it means there is a reduction in lag. Lower RPM’s are used to maximize boosts. Twin Turbo is great for street driving regularly. The setup of a Twin Turbo is more costly than installing a single turbo charger. V-type engines should use twin turbo chargers for maximum efficiency. Twin turbo provides smoother operation within the engine. Twin turbo does take up more space in the vehicle than a single. Purchasing two small turbo chargers are more cost efficient that the purchase of one larger one.

Single Turbo

When utilizing a single turbo, it will require all 8-cylinders to enable a boost build. A single turbo is great for drag racing where a very high amount of power is required. The setup of a single turbo is much simpler. You can acquire extra large setups that support more than 1500 horsepower. It has the ability to create some real power, but has a lag problem unlike the twin turbo. Some issues might happen during the setup but they are fixed simply and more cost efficient as well. It is compact and doesn’t require much space in the vehicle. It cools better. It is more cost efficient. It gives a higher boost at higher RPM’s. There is noticeable lagging. It is simpler to plumb since it is not required for cross plumbing the exhaust.

Keep In Mind!

Below 900 horsepower requirements can be dealt with fairly well with the use of a single turbo charger, however if you wish to create lag reduction, two small turbo chargers are what you should get. For the V-type engine layout, it is best to go with a twin turbo setup. For an Inline engine layout, it is best to go with a single turbo setup.

There are many vehicles that come factory made with a twin turbo system that you can convert to a single turbo charger. There are many who want to modify their single petrol turbo with that of a twin turbo system. This can depend greatly upon the type of car and type of engine that is being talked about. In many instances it will boil down to owner preference on how they wish it to be done.

For more information on Turbo Chargers or to receive help with your questions, please log onto http://www.rj-performance.com/.



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Stephen asked:


hi does any1 know is there anyway to adjust the turbo on a 1997 1.8 turbo diesel ford escort for slightly more boost. the turbo is a garrett it does not have an intercooler and it normally kicks in at 2000 rpm and turbo slows back down at approx 3250 rpm.

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Adrian L asked:


i own a ’96 civic ek which i have changed the engine to a b18c on may 2004… it was my first car, which i had gave my sis to drive… recently, my sis gave it back to me, so i took my t55 garrett from my FTO n put it in the b18c… i ran well but after 2 months, my whole engine blew up… pistons, etc… the turbo blew up as well… that turbo was bought march last year n ran well on my FTO… how could this possibly happen? i revved the engine to 9000+ rpm before it blew up…. without the turbo, it can easily be revved to 10000+ before hitting 2nd gear…. is it bcos the turbo is not configured too well on the b18c or is it bcos i revved it too high? #turbo boost is set to 1.5bar

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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

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

Eric Ferguson asked:


If you’re interested in adding power and performance to your ride, no doubt you’ve considered adding a turbocharger (just turbo to tuners), or a supercharger to your ride.  However, it can be difficult to determine which is the best for your needs.  For instance, what is the peak operating range of a turbocharger, versus a supercharger? How much horsepower can you gain from each and which is more cost effective?  Here are a few answers to your myriad of questions.

First, you need to understand how each system operates, before you can make an informed choice.  Both turbos and superchargers are a form of forced air induction.  In other words, they provide boost by forcing more air into each cylinder.  More air means more fuel can be dumped in, resulting in larger explosions, more rapid explosions and greater speed.  Basically, they provide more air, which results in longer, cleaner burns.  You waste less fuel, and go farther, faster.  However, that’s where the similarities end.

Turbos:

Turbochargers operate on spent exhaust gasses.  These gasses enter one half of the turbine, propelling the turbine and forcing compressed air into the engine.  The drawback to this method is that the air is very hot (use an intercooler to combat the heat) and the turbo operates at a fairly high RPM rate (75K to 150K RPMs).

Superchargers:

Superchargers are a little different from turbos.  Unlike turbos, they do not operate on exhaust gas.  Instead, they use a pulley and the belts on your engine to drive the impeller, rotating screws or rotors.  This forces air into the engine, providing more boost for your ride.  Superchargers operate at a lower RPM rate than do turbos (anywhere between 15K to 40K, depending on the type of supercharger).

That’s all well and good, but which is better, you ask?  That depends on what you want.  Both systems cost approximately the same (there will be a few dollars difference, but not much).  However, superchargers experience much less lag than do turbochargers. This results in more immediate power.  However, turbochargers can provide more boost at higher rates of speed, meaning that you get more out of them at higher RPM ranges.

Turbochargers also create more boost surge, which can damage engines, as well as creating additional backpressure that must be forced out through the headers.  Superchargers produce more noise than turbos, but are generally longer-lived, providing you with a longer lasting performance enhancement.

In short, it comes down to personal preference.  Both devices provide an amazing boost to your engine performance, knocking your speed capabilities up dramatically. Both systems have pros and cons associated with them, as well.  You choice will also depend on your usage.  For instance, a supercharger is ideal for a street machine, but if you are going to the track, a turbocharger offers better benefits. Before choosing either system, you will need to define your needs, as well as any future use of your ride, in order to make the best choice.

 



Calvin

Marc Formeister asked:


It’s obvious that when it comes to bolt-on modifications for your import car, turbocharging is far and away the best bang for your buck.

But what about supercharging your import? Just like turbochargers, superchargers produce boost pressure, but instead of being driven by exhaust gases alone, they’re driven via a belt on the crank pulley, meaning they contribute to parasitic power loss when the engine isn’t yet in boost. Additionally, there aren’t nearly as many supercharging kits designed for imports as there are turbocharging kits. So while yes, supercharging can add just as much power as turbochargers, turbocharging is much more common in the import car community. This popularity translates into a plethora of good, sound online information and advice about turbocharging, meaning if you have a question, it’s probably already been answered in some online car forum. You just need to search and be patient!

Turbocharging an engine that wasn’t designed for forced induction is not for the fainthearted, nor the mechanically-disinclined. It’s a very involved, expensive, time-consuming and headache-inducing project. But in the end, when you are finally treated to the visceral rush of being pinned back in the seat of your car by a turbocharger that spins at 120,000 rpm and howls an intoxicating jetlike song, you’ll know right away that it was all wholly worth it.

But before you get carried away with the obviously impressive final results of a successful turbo installation, you should know just what it is you’re getting into, and how much money you’re looking at. The importance of thoroughly researching this project first cannot be overstated. The more you read, the more prepared you’ll be, and the less likely you’ll be cursing at that one seemingly insignificant, but oh-so-important component that you overlooked. You’ll also have a much better comprehension of how a turbocharger system works and how you can troubleshoot potential problems.

You can start the research here. The following is a bare-minimum list of the parts needed for any custom low-boost turbo installation, regardless of the car. (Each part will be discussed in-depth in forthcoming articles, so stay tuned!)



*these prices are rough retail estimates for new items*

-turbo (duh!): $500-$700

-turbo manifold: .$300-$1000

-turbo inlet piping (steel): $25

-blow-off valve or bypass valve: $150

-air filter: $40

-downpipe: $150

-oil drain line, weld-in bung, and fittings: $40

-oil feed line and fittings: $40

-various silicone couplers: $100

-Around 8-10 quality stainless-steel hose clamps , preferably t-bolt clamps: $83

-air-to-air intercooler: $230

-intercooler piping (regular steel): $75

-intercooler piping (aluminum): $150

-fuel management—piggy back air/fuel controller: $400

GReddy E-Manage

Apexi AFC-Neo

-fuel management—retuned ECU: $600

-fuel management—full standalone: $1500

AEM EMS

-larger fuel injectors (if using re-tuned ECU or stand alone): $260

-fuel rail, if using different style injectors: $150.0

-brackets

-vacuum hose of various diameter: $20

-gaskets for turbo manifold, downpipe, etc: $20

-miscellaneous hardware and fittings: $20

Parts that you ought to buy if you’re at all concerned with your engine’s longevity:

-complete clutch kit: 

once your car is turbocharged, you’ll be making a lot more power, and stock clutches, especially if they’re high mileage, have a tough time handling the large increase in torque without slipping. It’d be a shame to get done with that whole turbo project only to find that you can’t transfer any of that glorious power to the ground! Advanced Clutch Technology offers reliable, reasonably priced clutches.

-oil cooler: 

Turbochargers will get extremely hot, so the oil running from your engine into the turbo via the feed line becomes quite hot after it passes through the turbo, cools the turbo, and drains back into the oil pan. If you can afford it, an oil cooler is a great investment even if the car isn’t turbocharged. Get one with a thermostat that turns on between 180-190 degrees, because cold oil is just as bad as really hot oil!

-boost gauge: 

A very good idea to prevent catastrophic engine failure due to too much boost; also lets you know if there’s any vacuum leaks anywhere in the turbo system.

-heat shield and/or turbo blanket: 

A heat shield will act as a barrier between the sizzling-hot turbo and important engine components that aren’t supposed to be hot, like electrical connections and power steering fluid. A turbo blanket, which is exactly what it sounds like, will drastically reduce under hood temperatures and therefore the temperature of the air being ingested by the turbo. A blanket offers the added bonus of a quicker spool up time due to the heat (energy) being trapped inside of the turbo.

-fuel pump: 

Usually in low-boost applications, the car’s OEM fuel pump will suffice; if you are planning on boosting substantially more than 8 psi, a fuel pump, such as the Walbro 255LPH, is necessary.

-wideband oxygen sensor and Air/Fuel ratio gauge, $279 (sensor only): 

Wideband oxygen sensors measure the ratio of air to fuel that is entering the engine at any given time. You can buy just the sensor and use your laptop to display the ratio, or you can buy a gauge so you always know what your precious engine is inhaling. This is an invaluable tool for tuning a turbocharged car.

So the total cost for piecing together your own turbo kit and turbocharging your car is $2603. (To arrive at this sum, the turbo manifold was $300, the fuel management was $400, and the intercooler piping was plain steel). Compare this to the price of GReddy’s turbo kit, which costs $3699 (for a Nissan 240sx). Of course, buying a bolt on kit is much more convenient than buying each part from its own place, and you are pretty much guaranteed that everything will fit perfectly and that you haven’t forgotten anything. But if you’re on a budget, you enjoy having options, and/or if you’re the type who likes to do things his own way (which is much more satisfying!), you can save $1000+ by piecing together your own custom kit. You can save even more if you buy used parts through online car fora or eBay, but stay away from buying a used turbocharger unless you can physically inspect it, because more likely than not they’ll need to be rebuilt.

Stay tuned for the next article on selecting the right size turbo!



O Reid