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Raising the efficiency of your turbo setup
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Alot of times engine builders speak about raising the air capacity of there engines through diffrent methods (IE :displacment up)which in turn raises the actual efficeincy of the engine overall . Thers diffrent ways of going at it but most of them we can get done ourselves. With a turbo engine it gets really shakey because there is alot more variables involved compared to an NA or atmosheric engine (Atmo=standard day barometric pressure at sea level is 14.7psi therefore an atomo engine dose not see more pressure than this at full throttle . With really efficient NA engines that are seeing massive amounts of air being prosseced at one time, you will actually start seeing boost or mild pressurization in the engine . A few psi is not much but it shows how hungry those cylinders can get at really high VE . )
So what are the things we can do?????? well first off when putting together a setup you have to have a goal and know, where do wanna end up. First off dont half*********. Why get small things here and there and waste money because of not having direction???? Get direction! Do you want a good street car or a drag car??????? Remember that the rule is this........A good street car will never make a good drag car and vice versa. With turbo set ups there alot of mistakes that you can avoid so your pockets wont go empty. First off you have to understand that the turbo dose not make the engine. If i put a monster turbo on a bone stock engine (a blow off valve dose not mean you are no longer stock) im gunnna be very dissapointed with the results over and over again. Its all about the powerplant and a turbo is the icing on the cake. Turning up the boost and blowing your turbo is a common thing but nobody understands why. When you turn up the boost and think that you are boosting saftley ,if your setup is restrictive you are actually boosting waaayyy higher than you think. Here's an example = Im looking at my boost gauge and i see that i turned the boost up to 1.5. Due to a stock intakemanifold ,restrictive throttle body , and improperly sized intercooler and piping that boost you see in your gauge is actually 2.0 kilo but you are only seeing 1.5 in the intake manifold . The turbocharger is actually overboosting and already surging and costing you power because it is surging . A compressor after it spins to fast will actually start be loose efficiency therefore blowing hot ****ty air at your engine. Your boosting oxygenless air . Its just like trying to light a match in space (oxygen+fire=energy . in an engine its Air+fuel+spark equals combustion). When you look at an actual turbo compressor map you notice that it shows how efficient your turbo is and what kind of boost can you run on it. If you exeed the boost levels you will not make power. A good example is the stock turbo on an RB20det. The stock t25 compressor cannot make anymore good power past 1.1kilo. Anything after that is just useless air that is hot. TURBO+tempeture are directly proportional to each other . Its all about how cold can you get the air with a turbo engine. Interccolers , the right size turbo(cold air equals effiecent air) the right boost levels ect....... Intercooler matching is also very important because that is pretty much what will get you in the ball park and far away from detonation and preignition due to hot*****air being forced in your precious investment . That saying "any intercooler is better than no intercooler" is totally wrong. If you do not match the right size intercooler to what you are doing ,or the compressor you are using you will not cool the air off and u will be choking your engine. The more area on the intercoller equals 10% temp drop per area added and power is directly proportional to that. Head work, intake manifold up grade and cams will hook u up big time when it comes it raising effiency. What you are doing is actually letting the cylinders breath more buy letting more air get actually processed. Intake manifolds if they are custom made have to be made for your cam and engine setup. It pretty much a fact that if you just throw high duration and high lift camshafts in, (properly degreed by the manufactures specs of course) you will never see there true potential because of the stock intake manifold. So your better off with the stock cams for most cases. If you look at the stock intake manifold you noticed that cars that have the same power band have intake manifolds that have almost similar length runners. Its pretty much dependant on runner lenth and size of plenum that will determin how you are gunna breath at high RPM. An example is a stock intake manifold that is on an engine that makes peak torque at 4500 RPM . If you start to rev higher like almost to 9000 RPM you have already out flowed the stock intake therefore you will loose potential power. Shorting the runners and enlarging the actual plenum you start to raise the amout of air avalible to your engine at high RPM . The shorter the runners the less torque at lower end but higher flow and power at high RPM. Theres more ways but after this its all about setup and what you are using for parts . OHH and how much money u got. I dont have to much so im gunna read read and read and find cheap poor people racing tricks and keep my investment at its full potential.
Wastegates:
Everyone seems to think that external wastegates make more power than internal actuated wastegates. When in reality, they don't produce anymore power than the other. It all depends the application and set up. You could run an internal wastegate, if your pressure ratio on your compressor side and exhuast side are about even. On bigger turbos, an internal wastegate will not be efficent due to boost spiking, reversion, exhaust pressure and temps being to high. But on a properly sized turbo, matched to the displacement of the engine, overall VE (Volumetric Efficency), and the power band your looking for, an internal wastegate can be efficient and do its job properly. Now when your set up becomes more extreme, running more boost, this is when you'll need to go external. More boost equals more exhaust pressure, and a smaller tuning window. When the exhaust pressures get to high, it will start pushing the internal wastegate shut. So either a bigger turbine housing/wheel is needed, or an external wastegate. Well ,people do not like to sacrifice spool up time, so a bigger exhaust housing will not please people.
Now running an oversized external wastegate can also cost some power. When you let to much exhaust pressure , your turbo will not spool up properly. Luckly, turbo kit manufactors have already properly sized the wastegate to what ever turbo they are selling. That means less math for us. But if your going with a totaly custom set up, you better make sure that your whole set up is proplerly matched to your engine.
Good luck
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492wrhp @25psi Pissed off granny cars.com
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