Just wondering what is the fuel pressure for a stock R? Also, I just purchased a B&M FPR, What should I set the fuel pressure too; engine is stock, except for a K&N 2710 drop in.

Thanks.

 

42psi

 

stock unless you get a wideband o2 hooked up on a dyno....and possibly V-AFC

 

Stock fuel pressure specifications are: 47-54psi

 

I see a FPR upgrade is in the works. Maybe you can run with the big boys now.

Port and polish of the OUTSIDE of the engine is not doing the trick eh?

STOP WASHING YOUR CAR hahaha


[Modified by Edwin, 11:36 PM 6/8/2002]

 

Well, I installed the B&M Fuel Guage, my pressure was at 40 psi. I then installed a B&M FPR and set it to 45 psi. Should I go higher????

Edwin, dont worry about the condition of my car.... Just START DRIVING YOURS MORE THEN 5 KM's A DAY.

Thanks for all the help.

 

You're remembering to remove the vacum line off the regulator when making your measurements I hope! Don't forget because it is meaningless unless you do.


If your fuel pressure was sitting at 40psi before you added the adjustable FPR then that might explain some things...

Have you put in the FPR yet?

 

Yes... the B&M gauge gave me a measurement of 40 before the addition of the B&M FPR, however, this is with the vacum line on at idle. Why does the adjustment in fuel pressure need to be made with the vacum line off?

I notice when I make the adjustment with the vacum line off, once I re-attach the vacum line the pressure will drop

 

I hope this makes sense:

The fuel pressure that is measured on the gauge is relative to the AIR pressure measured by the FPR. The hose that connects the FPR to the intake manifold is what the FPR uses to measure AIR pressure.

When the vehicle is at idle the AIR pressure inside the intake manifold is considerably less then 1 atmosphere so the relative FUEL pressure will be lower. This is by design and they way it should be.

What is important to consider when setting the fuel pressure is that it is to be measured relative to normal atmospheric pressure, which is why you open the FPR to the atmosphere when setting it. Setting the fuel pressure with the vacuum line attached is WRONG and can lead to engine damage! Do it right, with the vacuum line off!

The reason the fuel pressure is measured against the vacuum inside the intake manifold during normal operation is so that a constant fuel pressure drop may exist across the fuel injectors. Remember that the fuel injectors see fuel on one side and the intake manifold on the other. By keeping the fuel pressure constant relative to the intake manifold pressure you insure that the fuel injectors deliver the same amount of fuel for the same duty cycle.