What Fuel Pressure with mods

LBS Blown Buick

New Member
Joined
Apr 11, 2002
What fuel pressure is everybody running at?

My mods are as follows:
3.4 pulley
SLP Cold air box and filter
Exhaust u-chanel removed
2 steps colder spark plugs
180deg stat
AFPR set at 56psi

At WOT
I see 12.0 to 13.0 psi of boost, and 5 to 7deg of knock retard
O2's @ 900's
 
I don't have an AFPR, but you seem to be getting alot of boost from that 3.4 pulley. And some knock too. Seems like you need some more exhaust mods.
 
I also removed the screen in the MAF/TB.
Yes the boost is a bit high, I agree with the Exhaust need.
I don't know what exhaust to go with, I'd like good flow but it must sound good or quite.
 
Recorded a lot of data yesterday and ended up setting the AFPR @ 61psi.
Results:
2deg to 4deg 0f knock retard
O2's @ .924
13. psi of boost
Feels stronger and the pulls are smoother

next I set the fuel pressure back to stock 52psi
Results:
8deg to 11deg of knock retard
O2's @ 860's
13. psi of boost
A loss of power above 4000rpm
also I noticed the graf of rpm climb is verry unstable @ 52psi
and verry smooth & steady climb all the way to 5600rpm @ 61psi

Hope to play with it at the track soon and maybe some dyno time
@ RTB motor sports
 
More results: (DATA)
Well, this is Interesting,
Aparently adjusting the fuel pressure up causes the computer to lean out the LT fuel trim @ normal mid throttle driving to achive a 14.7 air fuel ratio.
I belive the computer uses this info to calculate the WOT fueling.
I notice that the LT fuel trim is now at -4% at WOT and the O2's are back in the 800's and the knock couts are back.
Final result the AFPR is of no value for a street driven car.

Next test MAF translater.
 
try a 160deg. stat. 54psi on reg. with vac line off and pluged. 100 oct. unleaded race gas, and ice down the blower. 3.4 pulley should be 10-11psi, you must be stacking up boost.
 
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