Hi guys,

I just installed an adjustable fuel pressure regulator on my S4 N/A

The stock pressure is about 2.4-2.8 kg/cm2 right? Now my question is..... How much can i increase the pressure?
The car only has a direct air intake and the exahust doesn't have any cats...

Thanks.

 

I wouldn't increase the pressure at all. Set it to the stock level.

 

Hmmmm.... Why do you say that?

 

I would really love to get more oppinions on this one.....

Is it allright if i set it to 3.4 - 3.8kg/cm2 ?

 

Dont change it mate.
no advantage and will put all your fuel trims out on your current settings.

 

The cars already run rich as it is, increasing the fuel pressure(and running even more rich) wont create more power.

 

Now that you have your fpr, you need to buy a turbo, manifold, downpipe, misc oil and coolant lines, t2 uim, adaptor plate for na to t2 uim, t2 throttle body, throttle cable t2 boost sensor, intercooler, piping couplings and clamps. If not its just gonna run worse with a fpr on an na.

john ny

 

The stock computer controls the fuel injectors by opening them for a certain amount of milliseconds based on a factory pre-set map. If you increase the fuel pressure, more fuel will be injected into the engine for each millisecond, which will cause the engine to run rich, reducing power and gas mileage.

The fuel rail pressure should be set to the stock pressure unless you install an aftermarket fuel controller or engine management system and the engine is re-tuned accordingly.

Not true. The NA will run better if it is retuned by a competent tuner with a fuel computer or standalone engine management system. A quality fuel pressure regulator like those from SX and Aeromotive will help a great deal in this case because it will allow for more accurate fuel metering.

 

Hmm... ok guys thanks a lot for the information!

So it won't do any good unless i get a standalone engine managment system... I think i'm going to start thinking about getting one then.

Thanks.

 

You can use a simple piggyback fuel computer like the Apexi S-AFC to tune the air/fuel mixture, but a standalone EMS will allow for finer tuning, ignition control, and elimination of the airflow meter and 1980's vintage stock computer. However, it is very important to understand that a novice is not able to tune the engine properly, so you will need to take the car to somebody who knows how to tune rotary engines.

 

Sure! It won't be me tuning up that kind of stuff... lol
Once i buy it i will take the car to a professional