[Pittsburghsvt]

Hey guys, Its been a real long time since ive been on here because I put my stang project on hold for now. My friend on the other had just finished his and we ran into problems. Hopefully somebody can help..

What we have is: 302 with beefed up bottom end(h beams, scat crank, forged pistons...) Edelbrock Victor?? heads. Trickflow upper and lower intake 70mm tb. long tubes, stock igntion,255lph fuel pump, 42lb injectors.. 5 speed stock tranny.. Im not 100% on the setup but that should give you a good idea

The car has 11lb pulley on it right now, and we were seeing around 9.80 lbs of boost on the dyno, but the car was going real lean around 4900 rpms..

Brought it back home, checked to make sure we didnt have any kinked lines, dropped the tank to make sure all the hoses and lines were good(the are).. we are stumped... The maf is not pegging according to the guy tuning it..

The fuel pressure is 38 at idle, around 50psi at wot..

Any help is appreciated, sorry for being long winded, hopefully I didnt leave anything out..


Ryan

[Pittsburghsvt]

I just found out it is a ATI procharger P-600b.. I guess it is kind of an older model.

[ryans88gt]

You shouldn't be anywhere close to going lean, but you'll probably need a custom chip burned.

[Goblin]

How lean are you talking? What was the A/F ratio?

[7-up man]

intercooled?

Im having similar issues with my current project. wish I could help you but im stumped as hell with my car.

347
ATI D1 @ 15 lbs
good fuel pressure (similar numbers to yours)
60 lb injectors

going lean as hell @ 4000 RPMs

will let you know if I figure out the issue.

[Pittsburghsvt]

Originally Posted by ryans88gt You shouldn't be anywhere close to going lean, but you'll probably need a custom chip burned.

Well we were at the dyno shop.. they use sct and he did burn a chip.. tried to manually add fuel on the top end, but for now we put a rev limiter at 4800 so we dont over rev and pop a motor..

Goblin How lean are you talking? What was the A/F ratio?

Im not 100% but i wanna say it was going up close to 14/1 from a steady 11.8 -12 during the climb up through the rpms..

7-up man intercooled?

yes it is intercooled, and we had a big fan supplying plenty of air..

[ryans88gt]

Give Bob Kurgan a call, he'll get things straightened out for you.

There is no way you should be going lean with 42 lb injectors unless you have a serious restriction somewhere. Since you saw the fuel pressure at 50 PSI, sounds like you have enough pump and big enough line. Where were you measuring the fuel pressure from (the shrader valve or the regulator?). I would measure from the shrader valve on the rail.

42 lb injectors at 50 PSI should be enough to make well over 500 hp, probably 600.

[acmillr]

Originally Posted by ryans88gt Give Bob Kurgan a call, he'll get things straightened out for you. There is no way you should be going lean with 42 lb injectors unless you have a serious restriction somewhere. Since you saw the fuel pressure at 50 PSI, sounds like you have enough pump and big enough line. Where were you measuring the fuel pressure from (the shrader valve or the regulator?). I would measure from the shrader valve on the rail. 42 lb injectors at 50 PSI should be enough to make well over 500 hp, probably 600.

I don't think running 42#er's up beyond 500 on a FI motor would be a wise idea. You are getting close to the limit there.

[acmillr]

Did you datalog the rail pressure throughout the entire run? What power level are you at before you go lean?

[ryans88gt]

Originally Posted by acmillr I don't think running 42#er's up beyond 500 on a FI motor would be a wise idea. You are getting close to the limit there.

Close to the limit?? I put down 515 hp with 30 lb/hr injectors and the A/F is below 12:1...that is with an FMU at fuel pressure at 90 PSI, but 42 lb/hr injectors are capable of a lot more power.

[acmillr]

Originally Posted by ryans88gt Close to the limit?? I put down 515 hp with 30 lb/hr injectors and the A/F is below 12:1...that is with an FMU at fuel pressure at 90 PSI, but 42 lb/hr injectors are capable of a lot more power.

If you turn the pressure up to 70+ psi, I guess you can get away with whatever you want. That just doesn't seem like a sensible way to tune a street car.

[95opal]

Originally Posted by acmillr If you turn the pressure up to 70+ psi, I guess you can get away with whatever you want. That just doesn't seem like a sensible way to tune a street car.

As long as the duty cyle is at or below 85%, I wouldnt suggest running more than that for a duty cycle. I dont see a problem with the 42s and the rest of his fuel mods.

[ryans88gt]

My fuel pressure at cruising is at 35 PSI, I drive it 100 miles a day when it doesn't rain.
I get 24 mpg and put down 500 hp. What isn't sensible about that?