North American Turbocoupe Organization



fuel pressure
rich Offline
Member
#1
Just put in a 255lph fuel pump and afpr. I am at 15psi of boost. I have an a4ld and I was wondering what I should set base pressure to?

Also is there any reason (aside from the known weaknesses of the tranny), now that I have sufficient fuel, why I should not crank it up to 18psi now?

Thanks
2.3L Turbo in 88 stang, browntops, 93 a4ld, volvo ic, broncoII rad, gillis valve set @15, k&n af.
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natmac3 Offline
Administrator
#2
I think the tranny, if it's been well maintained, could handle the extra power as long as you're not always dogging it. I wouldn't turn up the boost before getting a K&N and downpipe. The extra load on the turbo could cause problems if you don't increase its efficiency.

And as for fuel pressure, try 39-42psi.
1987tc
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rich Offline
Member
#3
Thanks! Is that 39-42 with or without the vac line on?
2.3L Turbo in 88 stang, browntops, 93 a4ld, volvo ic, broncoII rad, gillis valve set @15, k&n af.
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natmac3 Offline
Administrator
#4
39-42 Vac disconnected.

Some cars like fuel pressure closer to 42 while others are happier right around 39-40. If you don't mind changing and have a good fuel pressure gauge, I'd say pick one on the high end and see how it runs, if it's smooth and not coughing black smoke then you'll be okay, otherwise turn it down a little and see how it reacts...

I have mine set between 40-42...
1987tc
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rich Offline
Member
#5
Great info thanks. There is just one more thing. I have a 3" DP and K&N installed already, so 18psi should be ok to dial in?

I am at 15 now and have a gillis valve. If I turn the gillis valve so that no threads show, would the turbo just spool to it's max and fall off, or or is it gonna take some trial and error to find 18 on the valve? I guess what I am trying to say is should i just screw the valve in to the max and that will give me 18 or will that cause overspooling? Thanks!
2.3L Turbo in 88 stang, browntops, 93 a4ld, volvo ic, broncoII rad, gillis valve set @15, k&n af.
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natmac3 Offline
Administrator
#6
DO NOT MAX OUT THE VALVE!!!

Unless it has a really weak spring , it WILL cause overboost and you REALLY don't want that!

You should be fine turning up the boost, but I hope you are using an aftermarket boost gauge, as the stock one is notoriously inaccurate. When I turned up my boost way back when, it would pull like hell, then spit and studder... When I installed my VDO boost gauge and made a hard run down I-95, it pinned the needle at 30psi !!!

Be careful, be cautious, be well informed.
Turn it up slowly, listen for pinging, and take your foot out of it and turn down the boost if it knocks.
1987tc
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rich Offline
Member
#7
Thanks! Have a great weekend
2.3L Turbo in 88 stang, browntops, 93 a4ld, volvo ic, broncoII rad, gillis valve set @15, k&n af.
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