After doing a few searches and reading some things I've noticed some people stating that most stock L98s run a little rich. BUT, I've also read that you can gain some cheap performance by just turning you FP up a 3-5psi.

I've got all the air possible flowing in and out of my engine now without changing the intake manifolds, heads, or cam. (CAI, free mods, full exhaust).

Would I run rich if I turned the FP up a little just by shimming the regulator? I know it won't make a big difference, but I don't want it to hurt performance either and I don't have a scan tool.

Thanks again.
-Brian

 

The only way to really know if you would be running rich is to check the A/F ratio. Best bet would be to take it to a dyno with a wide band O2 acquisition tool. That's what I would do if I was concerned about it. But I'm not.

 

Well, i think that partly comes from the old way of thinking. More fuel, more timing = more power.

And it kinda works

But it isn't really your max available power, it can just be better than stock, especially in the SOTP feel in the low end. But leaner with less timing can be faster

But no, i would not recommend just shimming the FPR for fun. Just hang on a bit and buy one, or do the free one in vader's article. And use it in conjunction with real test and tuning and you'll probably be happier with the results.

BTW, i bet the TPIS dyno sheet in our FAQ probably had like liquid nitrogen on the intake or something to skew numbers that bad. Especially in that era magazines and such wer enotorious for doing crazy behind the scenes secrets for big numbers.

 

LOL more than likley

 

Raised my FP from 41 to 45 psi and did pick up some low end performance.

 

Actually, now that I think about it a little more... I thought the computer readjusts the pulse width so it doesn't actually burn any more fuel, it just sprays a little bit different pattern, (better atomization). Am I wrong?

 

It would trim it back at part throttle/idle in closed loop. But you could end up too rich at WOT. At the very least You really need an adjustable one. And some way too time your car to see if raising or lowering it helps your times. Or take it to a dyno and see if they can tune it some with an AFPR.

I agree...That TPIS stuff about the fuel pressure is crap.