Engine/Transmission (1998.5 - 2002) What is ideal fuel pressure?

[tractorface]

Lookin for opinions on what the ideal fuel pressure for a VP44 is. I run a FASS and volume is good. Was running around 18-21 psi depending on temps. Wanted to reduce because of concerns with High pressure causing damage to the VP over the long haul. Installed new spring and dropped pressure to 12-13psi at idle and never below 10psi at full throttle. I am of the opinion that this is almost ideal for an electric fuel pump syatem (notice I said Electric Rasp guys ) My Fass is fed with a 1/2'' Braided SS line sucking through a 1/2" pickup tube. All other lines with the exception of the VP44 return are 3/8". I have a 3/8" manifold with 5 ports for temperature, pressure, etc. in the line. My fitting to the VP is drilled out so the VP is the restriction here. My theory is that 10psi of fuel through the 3/8" hose is a greater quantity of fuel than 10psi through the OEM restrictive system. Where OEM systems see a pressure drop of 8-12 psi during a WOT run I only see a pressure drop of 2 psi during WOT.

Just looking for opinions on this cause mentally I sstill don't like seeing the gauge go to 10 psi. Trying to make sure my logic is correct. I can always change spring in FASS to adjust pressure. This is a very easy change. The fuel manifold will make filter changes a snap as I am putting a valve in for bleeding. Have noticed zero performance change since lowering pressure. I also hope a lower pressure will help the FASS live a long and happy life.

Thanks

 

[rkressg]

I do believe that specs are for between 8 - 17psi. You are correct with your thoughts with regard to volume (what really matters), with more volume, you move more fuel.



I personally run 16psi on the FASS and no matter how hard I push the loud pedal or how much black stuff comes out the back, the pressure never drops below 14psi.

-Rich

 

[GKinney]

pressure

My Fass runs about 14-15psi idling depending on ambient temps. I too have a 1/2" suction to the pump. Only way to go for a high volume pump I say!! I usually drop to 12-12. 5psi at WOT,, I'm happy with those #'s.

 

[Beast2B]

... and how often do you run it at WOT? (OK, daily, but for sustained periods?) I'd say it's a bit like EGT; 1200* sustained pulling a trailer, but 1500* on a dyno run, pull or drag race occasionally is acceptable (especially if it's a Ferd, Chebbie or tuner!)

 

[GKinney]

... and how often do you run it at WOT? (OK, daily, but for sustained periods?) I'd say it's a bit like EGT; 1200* sustained pulling a trailer, but 1500* on a dyno run, pull or drag race occasionally is acceptable (especially if it's a Ferd, Chebbie or tuner!)

Not very often @ $2. 20/gl. !! Numbers are for reference only,, just nice to know the fuel is there when and if you need it with out worrying about nuking the VP44. :-laf