I no how sc's work.. but I dont understand how u can adjust the PSI to get more HP. Can anyone explain this to me? I have atleast 1-2 years before I can afford a Stillen SC. And is it that hard to install???? I feel stupid asking these questions. But I heard people say, " only a fool doesnt ask questions"

 

you use a smaller pulley which makes the blower spin faster. This creates more pressure(psi) in the intake manifold, and forces more air into each cylinder..

 

And more air means you can inject more fuel, and more fuel means more power.

In effect, you are increasing the volumetric efficiency of the engine, which is always less than 100% for a NA engine (more like 80-85%), to significantly greater than 100% by forcing the air in instead of depending on just the vacuum created during the intake stroke.

 

ooh. Does that mean we get ****ty gas mileage?

 

your fuel economy is based on which FMU you use. the FMU that comes with the stillen kit is 6:1 and that means it will deliver 6 times more of fuel pressure per pound of boost. This FMU will support you up to a 3.33 pulley. When you use smaller pulleys than 3.33, you will need higher ratio of FMU to deliever more fuel to the engine so you will not run lean.

for a NA vehicle....your fuel pressure @ WOT is about 58psi.

for an SC/TC vehicle running with FMU...there is a formula to get your fuel pressure.

fp = (base fp)/2 + amount of boost * FMU ratio

I have a 2.87 pulley with an 8:1 FMU and I see peak boost of 10psi..my base fuel pressure is 40psi. so I am getting:

fp = 20 / 2 + 10psi * 8
fp = 100psi...that's two times higher than a NA maxima at WOT.


I am running super rich with this FMU and I only get 18-20 mpg per tank, local and highway mix....just like an old SUV.

 

Gas mileage doesn't have to be too bad because the supercharger doesn't affect gas mileage much unless you are boosting. During boosting the fmu and boost pressure determines fuel consumption, but during normal driving with the engine in closed loop mode the ecu is controlling the fuel use, just like a NA car.

I get a consistent 27 mpg combined city and highway, with an occasional boost for grins if it's not too hot out.

 

Quick questions.. Whats " WOT " "NA vehicle" and "FMU"

 

Wide Open Throttle
Normally Aspirated
Fuel Management Unit

also:

FPR: fuel pressure regulator
SAFC: super air flow converter (made by Apexi)
FP: fuel pressure (sometimes used for fuel pump)
AFR: air/fuel ratio
TB: throttle body
MAFS: mass airflow sensor
MEVI: middle east variable intake

 

seems like you still have some study to do~~~ but you are getting there. it's ok..I didnt know what an FMU is after my SC was installed and I thought the air-fuel ratio (AFR) is the same as my FMU ratio make sure you have all your questions answered before you make your next move.

 

It's good to ask questions. When I was in graduate school at Texas U I was the only American in a lot of the classes I took (mostly computational mechanics, elasticity and solid mechanics courses). The other students were all from a country and culture where asking questions meant loss of face, so nobody asked any. I was thoroughly intimidated and fell into the same mindset, sorry to say, and I didn't get much out of those classes. I got the most out of the classes that were filled with dumb Americans who weren't afraid to ask questions. So ask away! We'll all learn something if you do.