Ok today i installed my ported plenum and my homemade AFPR before i did anything i checked the pressure and it was about 35 psi,what would be a good fuel pressure to run for my car? or will i just have to experiment? im just tryin to get a ballpark figure for a good starting point, thanks.

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87 IROC-z 305 TPI
Borg Warner T-5 fresh rebuild
10-bolt 3.73 Richmond gears rebuilt GM posi,
formerly BW 9-bolt w/3.45 gears(broke it)
Ported Plenum and Runners Homemade AFPR
ACCEL 8.8 wires, High output coil,and cap & rotor
Bosch platinum + 4 plugs
Ram Air w/ K&N filters,
MAF sensor screens removed, TB coolant bypass
Polyurethane tranny and torque arm mounts
Dynomax catback w/custom tips
K&N oil filter,Mobil 1 synth, Futura GLS Super Sport tires 265/50/15 rear and 235/60/15 front mounted on 86 monte carlo SS rims ,

400 sbc and a 6 spd in the works

 

btt

 

I thought is was 43.5. But I cannot be sure on your 87.

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1991 Firebird
350 L98 (was a 305 TBI),T-5,Edelbrock TES and cat back,Accel manifold
NOS,subframes,jegster torque arm,MSD Digital 6
AFPR,Lakewood lcas
Hurst linelock,SLP cam (206 212 .480 .486),relocated battery,cold air,Hypertech chip,centerforce df,clutch
poly bushings and mounts
AFR 190s
Harland sharp 1.5 rockers
autopower rollbar

12.33 @ 114.83 juiced uncorrected

13.510 @ 102 non juiced uncorrected

 

I agree, it should be 43.5 for TPI........I think.......lol.

How did you check your fuel pressure???

 

They are right, it should be about 43 but that is with the vacuum line disconnected. The vaccum line is disconnected to set your maximum pressure. The pressure should be set somewhere between 46 to 50 psi for the 19# injectors. Every engine is different so some experimentation might be necessary.
I would start at 46 then increase it until either performance begins to drop, or mileage decreases.
Also if you set the pressure too high the ECM might not be able to reduce the injector pulse width enough to maintain proper fuel/air ratio and the engine will always run too rich.

[This message has been edited by Ozzy88GTA (edited October 22, 2001).]

 

A good ballpark figure to start at would ve stock, or about 43 psi with the vacuum line off. As it has already been pointed out, sounds like you are checking it with the line on, this is useless. Set it to 43 psi w/ the line off and go from there.

Now you need to get yourself to the track (or at least get a Gtech or something to do comparison measurements) and figure out where you need your FP to be. We could all give you numbers, but the fact is, the whole point of an AFPR is to use it to tune your car. Make a couple runs, amke sure they are showing a clear consistent trend. Then bump the FP up 2 psi and take a few more runs and see what it does. If faster, bump up 2 more psi and repeat. When it slows down, go back to the last fastest setting.

 

ok i didnt know about the vacuum line deal, so that explains why it was so low, thanks for all your help, i will set it to 43 psi tomorrow, and spend some time at the track once i get some new back tires, thanks guys

------------------
87 IROC-z 305 TPI
Borg Warner T-5 fresh rebuild
10-bolt 3.73 Richmond gears rebuilt GM posi,
formerly BW 9-bolt w/3.45 gears(broke it)
Ported Plenum and Runners Homemade AFPR
ACCEL 8.8 wires, High output coil,and cap & rotor
Bosch platinum + 4 plugs
Ram Air w/ K&N filters,
MAF sensor screens removed, TB coolant bypass
Polyurethane tranny and torque arm mounts
Dynomax catback w/custom tips
K&N oil filter,Mobil 1 synth, Futura GLS Super Sport tires 265/50/15 rear and 235/60/15 front mounted on 86 monte carlo SS rims ,

400 sbc and a 6 spd in the works