LHVETTE

Does anyone know if a aftermarket fuel pump without a vapor return line will cause the fuel pressure to drop to 1 to 2 psi from 7psi after the engine reaches operating temperature. If so is the only fix to go back to a factory fuel pump or electric fuel pump.

Nemesis_152

i'm not sure of the exact response to your question, but if the car runs fine at 6psi, why mess with it?

MotorHead

I take it you are monitoring the fuel pressure with an after market oil filled gauge on your fuel line ?

If so remove it and throw it in the garbage, they don't work most of the time after they get heated up

LHVETTE

Wow, thanks for the input, but why does the pressure gauge quit working?

76 sting

heat expands cold contracts....I faced the same thing now I am putting one in the car not the engine bay.

mikem350

FYI, in car press gauge must be electric with the sender at the fuel line....

76 sting

Thanks, but there is an alternative. I am using a mechanical with an isolator.

Mike Ward

Why monitor fuel pressure at all? It is one of the least meaningful parameter.........

76 sting

Maybe for you, but if your running NOS you better have one visable at all times.

Nemesis_152

wouldn't a pressure switch to kill the nitrous circuits be faster, safer (for your well being) and more reliable than watching the gauge yourself?

76 sting

You are correct and both should be used. One is for safety in case it goes lean (pressure switch) and the gauge can be used for better understanding where on the RPM scale that it is happening. Also, when not running NOS you can use the gauge and make sure that the pump is supplying the correct pressure all the way through WOT while at the track.

Mike Ward

If you're driving with NOS and need to fixate on the gauge reading, I'd prefer you actually be looking out the windows and not running into me or anyone else on a public road.

76 sting

I never mentioned driving with NOS on the road. I guess I need to further explain so folks don't make assumptions...my use is 1/8 track not road use. I would not be stupid enough to use this on the street and you don't stare at gauges you look at them for 1/2 a second. Are you telling me you don't look at your gauges?

Nemesis_152

not after the burnout

76 sting

Mike Ward

Thanks for the clarification on the street vs. track. I believe the OP is using his car on the street only, so your words of caution are not applicable to his situation.

From what you describe, monitoring the fuel pressure gauge is essential to the preservation of engine health and must be done throughout the NOS shot.

There are no gauges on a street driven Corvette that have that level of criticality. Yes, I glance at mine from time to time but it's more for entertainment value than precautionary given the inherent reliability of an SBC.