I just got my 355 TPI running for the first time in 6 months this past weekend. I finally put on headers and just adjusted my fuel pressure today. Without an exhaust the engine sounds really mean, but when I gave it an extra 10psi fuel (now at 46psi), as soon as I give it just a little throttle the engine just screams...it's very touchy.

What kind of gains should I expect from this at the track? Is TPISs claim of 30hp and 150 ft/lb gain at all accurate? I really didn't think changing my fuel pressure by 10psi would do so much to my throttle response.

What kind of gains at the track have you guys noticed with adjusting your fuel pressure? I was running a 14.4 using 35psi fuel and stock exhaust manifolds. I'm hoping to get into the 13s with headers and higher fuel pressure...think it's possible?

I can't test this on the road or track as my truck still looks like the picture below.



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1982 S-10 Wildside
355 TPI, Accel High-Flow Intake, Ported Plenum, Arizona Speed & Marine Runners, TPIS AFPR, Edelbrock BBK 52MM Throttle Body, Sanderson Ceramic Coated Headers 1993 Typhoon Drivetrain

 

What size injectors are you using on that engine and what computer are you using?? As far as the fuel pressure.... if the engine wants more then you're probably gonna see track times get better with more pressure... but here's a good rule to go by.... if you hit 50psi and your engine still wants more, then you need bigger injectors.

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1986 Trans AM
355 TPI
4 Wheel Disc Brakes
9 bolt Borg Warner Rear (2.77's....oh joy) :P
6" rods, approx. 9.7:1 Compression, Stock TPI (soon to be ported), 24#/hr LTI injectors (cleaned and flowmatched by Cruizin Performance), Hedman Shorty Headers, 3" exhaust with 80 series flowmaster, SBC 993 heads completely redone and modified for 1.6 RR, 1.52 RR (for now), Comp Cams XE262-14 TPI Cam, Holley AFPR, TPIS airfoil, MSD wires, MSD 6-AL Ignition, Hypertech 53,000 volt coil.

Track times to come.

 

I'm using the stock 22# injectors. I had Rich clean them though. I think 24# is probably overkill for this motor.

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1982 S-10 Wildside
355 TPI, Accel High-Flow Intake, Ported Plenum, Arizona Speed & Marine Runners, TPIS AFPR, Edelbrock BBK 52MM Throttle Body, Sanderson Ceramic Coated Headers, All Wheel Drive

 

Hey,

I hit 55lbs and my motor wouldn't idle. My A/F ratio gauge lit all the way up. I'm running almost 50lbs now and it seems ok.

I was having a breathing problem tho, and still am. I'm not sure what your running for
induction stuff, asside from the K&N you have mounted over the radiator.

What are you running for heads and cam?

-- Joe


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1989 Formula 350 4-bolt mains, Forged .030 TRW pistons, SLP 51010 Roller Cam, Comp-cams roller lifters, Summit 1.5 roller rockers, World Products Sportsman II
2.02/1.60 heads, Edelbrock TPI Intake, Cloyes Double Roller, timing chain, Mellings oil pump: 13.5 @ 100.23 MPH

Since close of track : Ported SLP runners, Ported Plenum, AFPR, Autometer 100lbs gauge, A/F ratio gauge.

http://www.joesperformance.com

-- Joe

 

Over 50psi is hard on the fuel pump... even a good aftermarket one. If you insist on sticking with the 22# injectors then don't risk going over 50psi fuel pressure even if that's what the engine wants.

 

150 ft/lb gain? Well don't believe the hype. I wouldn't even believe the 30HP gain as advertised.

I would say you can honestly gain 2 tenths at the track when you find your perfect ful pressure.

BTW, the 35 lb setting you was using is way to low anyway, no wonder it made a big differance.



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86 Camaro Sport
LT1 Induction
383 Speed-O-Motive Crate Engine, Raptor 700R4 Tranmission, Trick Flow Twisted Wedge G2's, 58mm Accel TB, 3.73 Auburn Pro, SLP Cold Air Induction and Headers, Hooker Cat-back, Serpentine Belt Setup, Dual IROC Fans, Jamex springs, 16" IROC Rims, 36mm/24mm Sway Bars, Global West Steering Brace. Hotchkis Rear LCA's,Panhard Bar and SFC's.
My Camaro Project
Moderator at SE ThirdGen

 

If the motor needs more fuel and you dont have a prom burner. An increase in fuel pressure will help. Some time on a dyno with a wide band o2 sensor would be good.

Ive found that my car likes 47 psi. Even having access to prom burning. It just seems to be more responsive at that pressure.



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90 IROC
SuperRamed 406
Trickflow 23* heads

 

I can't get my truck on a dyno because it's all wheel drive. I'm not aware of any 4 wheel dyno around here. I'll gust have to play with it at the track.

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1982 S-10 Wildside
355 TPI, Accel High-Flow Intake, Ported Plenum, Arizona Speed & Marine Runners, TPIS AFPR, Edelbrock BBK 52MM Throttle Body, Sanderson Ceramic Coated Headers, All Wheel Drive

 

I agree with Mike, in fact, I feel the best thing to do is raise the fuel pressure between 46-48 psi (for the good atomization, yet not too high to prematurely burn out your pump), and then adjust the eprom fuel tables.

I believe that you need to do both (higher pressure and altered eprom) to optimize the fuel. With eprom burning, you can concentrate on the fuel pressure you want to give the best atomization and alter the Injector PW to ensure it is at the proper mixture.

 

All wheel drive...Thats awesome.... I bet that thing will come out of the hole pretty hard. Didnt you post a video clip of your truck last year? I think Ive seen it before.

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90 IROC
SuperRamed 406
Trickflow 23* heads

 

I have 8 videos on my homepage.

http://www.personal.psu.edu/users/m/d/mdn124/wildside/

The low end torque from TPI is a great combo with all wheel drive. Gives you a sick feeling in your stomach like a rollercoaster ride.

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1982 S-10 Wildside
355 TPI, Accel High-Flow Intake, Ported Plenum, Arizona Speed & Marine Runners, TPIS AFPR, Edelbrock BBK 52MM Throttle Body, Sanderson Ceramic Coated Headers, All Wheel Drive

 

Yeah it gets out of the hole, damn, that thing just goes......

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j.wolfe
_ ____ _
91 GTA L98 MSD K&N 195,000
Best time: 14.389@95.49 (VMP) Done with 193,000 miles and no engine work what so ever.
"...Deception..." Brandon Sloan * ...wounds heal and chics dig scars...