North American Turbocoupe Organization

Full Version: Stock FPR
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Hey guys,I don't know if I saw this tech article on here or turboford,but wasn't there an article on "cheating" the stock fuel pressure regulator out of a few more PSI of fuel pressure? If it was here,can someone point me to it? Also,does anyone have any idea of how much boost it's safe to run with a brand new stock fuel pump?I don't want to be replacing a head gasket from running lean.BTW, the car is a '86 TC
What Mods have you done? Turning up the fuel pressure on a marginal fuel pump may not accomplish much. Pumps usually can supply less fuel at higher pressures so this can be a self defeating strategy unless you got a pump that can still supply needed volume
The only mods I have done so far are a Gillis boost valve,K&N cone filter.Honestly,I'm not sure if I need more fuel pressure,It does rise # for # under boost, and my tailpipe is pitch black. Under boost at the top end of the rev range it feels like it leans out or runs out of fuel.Even my dad says it feels like it runs out of fuel.It seems to pull more consistently and smoother if I turn the boost down to around 14 PSI.Or could running rich be causing me problems? I understand you guys can't give me a definite answer on my questions because I don't have a wideband,I'm still using the stock boost gauge,and right now everything is being tested by "seat of the pants" feeling.Oh yeah,if it matters,my timing is 12-13 degrees spout out. I had the fuel tank out last year and replaced the fuel pump with a new stock pump.I know,I'd like to shoot myself now for not putting in a Walbro.
The computer is programed to dump fuel at WOT, regardless of boost pressure (the computer doesn't know, especially with an aftermarket boost controler
Next time try lifting slightly, say 90% throttle instead of 100%. See if anything changes.
Yeah,I've done that before.It feels a heck of a lot stronger at 90%,then I give it 100% throttle and it falls flat a little.It's still strong at 100%,I just thought there might be a way to adjust it out.Thanks for your replies! Smile
I seen a trick a while back (I think it was for a 10 second dodge caravan minivan or something) where he crushed the FPR little by little until the desired pressure was reached. I don't know the details, but it sure seemed to work.


(EDIT) Found the link...it's not 10 sec, but still impressive!
http://www.gusmahon.org/index_main.htm
The problem with reducing fuel pressure to lean out the top end is that it may become too lean somewhere.

I would do ALL the fuel system diagnostics before making any pressure adjustments. This way you know what kind of pressure you have under all conditions.
http://www.turbotbird.com/techinfo/Fuel_...ostics.htm
If you have a fuel pressure gauge that you can see while driving, what does it do when it's falling off? Is the increase nice and steady as high as you're boosting? What is the base pressure (no vac line)?

Gus was a true hot rodder. You can follow his example and crush the fpr a little at a time and test it.
(shameless thread tangent)

ironic that my dad was mentioning I needed a van to haul around the family this weekend.....

(whistles a tune... walks away slowly)