Stock Fuel Pressure

[Justin]

I just got my AFPR in... I have a Walbro, J-Tube bypassed, and the FPD Bypassed. Stock injectors, until I get mine back from RC Eng getting them cleaned.

1. What's stock fuel pressure?
2. What's ideal fuel pressure? What should i set mine at?


I searched, but I'm lousy at it and can never find what I'm after....

 

[drjonez]

IIRC stock base = 37-42 PSI

 

[mhopemk3]

I thought it was the low 30's on vacuum.. Maybe I had to set mine @ that due to the 550's.. :dunno:

 

[jdub]

Per the TRSM:
http://www.cygnusx1.net/supra/Library/TSRM/MK3/manual.aspx?Section=FI&Page=73

 

[Justin]

33-40 psi, that's an awful big difference. Is there a benifit to 33 or a benifit to 40?

 

[mhopemk3]

So it's low 20's on vacuum.. HMMM..

 

[jdub]

33-40 psi, that's an awful big difference. Is there a benifit to 33 or a benifit to 40?

My Lex/550 set-up seems to run best at 25-27 psi vac on.

 

[rumptis]

Does the Pressure raise then with boost? If so how much per PSI of Boost?

 

[jdub]

Yes...as you add power, vac reduces and turns to pressure under boost

Can't find the ratio for the stock FPR...the Aeromotive raises pressure 1:1 to boost.

 

[jetjock]

Looked at another way the Toyota Type A fuel system used on a stock Supra keeps the sum of manifold pressure and fuel pressure at a constant 36 psi ie; they'll always be a delta P of 36 between them. If this were not done injected fuel would vary with manifold pressure for the same fuel pressure and injector duration.