Fuel Pessure questions?

[FlaBoy]

WEll, I got my new adjustable FPR from accufab installed today. The little instruction sheet that came with it reccomended 42 psi (with vacuum line off) and said it should drop about 10 PSI with the vacuum line back on. I set mine at 42 PSI static, and when I put my vacuum line back on, my fuel rpessure only drops about 4 PSI. I was wondering if this is normal, if not, how big of a deal is it, and what I should do to get it right. Also, what are some of you guys running fuel pressure-wise, or what would you reccomend? MY car is a pretty much stock hot-air, I've got a walbro 340 and hotwire kit, and '87 coil, but so far as i know everyhting else is stock (i'm jsut kind of assuming the injectors and chip etc. are). Thanks for the help!

 

[HOTSIX]

Ya my results have always been the same as you.

Not sure where the 10 PSI thing comes from........

 

[Jerryl]

4 PSI is not much of a drop, but that depends largely on the vacuum your engine is pulling. Either way, I do not belief it is a 1:1 ratio of the vac side as it should be on the boost side of the equation.

My car liked the FP around 37.5 PSI setting (on my guage). I know what the AFP reg instructions say but you really need a scantool or a wideband to find the correct FP setting. I belief stock fuel pressure was listed around 35-40 PSI. There is no "magic" FP setting as all cars are different.

As you upgrade, the chip writer will have a recomended spec to be used as s starting point, and at that time, I would start there. Usually 42-44 PSI.

 

[Bryan C.]

When mine was bone stock it liked 38#.