How much fuel is needed to produce approx 425?

[Dan Gray]

I have a 331 stroker motor in my 89 hatchback(can look at sig to see excatly what i have) that im running 115mph in the quarter. But since i built this engine last year i feel that it is running too lean. The plug colour at the end of the track is always too clean/white for me. If I play around with the fuel pressure at the track, the higher the pressure the more MPH i can pull out of the car until i hit about 60PSI fuel pressure. And even then i can only get a tan out of the plugs. I don't feel i should be having to run the fuel pressure that high and im thinking my injectors are too small or my fuel pump is too small. When i built this engine i was aiming for around 400-425 hp so i installed 30lbs injectors. Have i gone too small? SHould i have install 36lb. Im also running a 190lph pump. But at 60PSI fuel pressure am i getting enough fuel to feed the engine or should i step up to a 255lph?

Thanks
DAn

 

[Mike92GT]

Have you had it dyno'd? The best way to determine if your running lean is to put it on a dyno with an a/f meter or buy your own wide band o2 so you can check it yourself. That way you know your exact air/fuel ratio instead of trying to tune by the seat of your pants, so to speak. 30lb injectors should be enough for your combo in my opinion, however going to a 255 pump might not be a bad idea.

 

[Mike92GT]

I just realized your in Canada, my bad. I don't what you have in the way of chassis dynos up there...

 

[Dan Gray]

WE have lots of chassis dyno's up here. Ya im going to do that this year.

 

[SQUEEZE&STROKE]

Go with the 255. On my f/i 331 I ran 36 # injectors...but I also have victor Jr's and 11:1 compression

 

[2000xp8]

I'll bet your C&L meter is the problem, because a 155 pump, with 30's will support 450 without running 60psi. (this is NA does not apply to a supercharged car)
I know these numbers as to be facts, not hearsay. Including one car with that exact fuel setup that made 444 to the wheels on a 347, and ran to about 6500 rpm. In a car that went 10.70@124 all natural.

Before everyone jumps down my throat about the C&L opinion, spare me, i know if you have one, you love it, and it's great, but this is a serious setup Dan has, not some mild 250 rwhp car.
They can definetely throw a cars fuel mixture off.
I suggest an 80mm Pro m. You can take the advice or you can leave it.
Dan, nothing personal with you here, but every time i make a detrimental comment about C&L everyone that owns one freaks out. My info is from more than reliable sources.

Now 36's won't hurt, nor will the bigger pump, i just don't think that's going to cure anything. People tend to judge fuel demand based on what they see with a supercharged car, and it's not nearly the same NA.

BTW, nice combo, you should be able to get 120mph+out of it, when it's pefected.

 

[Dbeck002]

Personal experience with the C&L.

It gets the job done for a daily driven car, not for a racecar.

The brain of the engine is that MAF, get a pro-m 80mm universal. its expensive but it'll be your best investment.



I only make 302 RWHP 331 RWTQ with my stock bottom end and aftermarket heads/cam.

Even so, my dyno tuner told me to get rid of the C&L because its garbage. He swears by the PRO-M, he told me I could hit 315 RWHP no problem if I swapped just the MAF to the 80mm PRO-M. Do it before you do anything, then dyno tune your car. Then come back to us. Hope this helps.

 

[vristang]

I have a 331 stroker motor in my 89 hatchback(can look at sig to see excatly what i have) that im running 115mph in the quarter. But since i built this engine last year i feel that it is running too lean. The plug colour at the end of the track is always too clean/white for me. If I play around with the fuel pressure at the track, the higher the pressure the more MPH i can pull out of the car until i hit about 60PSI fuel pressure. And even then i can only get a tan out of the plugs. I don't feel i should be having to run the fuel pressure that high and im thinking my injectors are too small or my fuel pump is too small. When i built this engine i was aiming for around 400-425 hp so i installed 30lbs injectors. Have i gone too small? SHould i have install 36lb. Im also running a 190lph pump. But at 60PSI fuel pressure am i getting enough fuel to feed the engine or should i step up to a 255lph?

Thanks
DAn

That pump and injector sizing should be about right (but you could go up to 42lb and still be at ~60% cycle with 40psi, I have an excel calculator or I can post up the formulas if anyone cares). If you are still getting lean at 60psi, I would look elsewhere for the problem. Something like bad O2s or ECT/ACT? As suggested your MAF could be causing some problems.
The above comments by 2000xp8 are not the only neg. things I have heard about C&L meters. However, I am running one w/ the stroker in my sig, and seem ok. There are many factors there.

I think the only way to really get any accuracy with the fuel ratio would be with a tuner or dyno session.
When you complete a pass do you shut the motor off at full throttle (or close to it)? From what I have read this will make a big difference in plug readings.
jason

 

[Dan Gray]

Thanks everybody. I do run the C&L meter and at the time many years ago that i bought it, it made i huge difference over the Pro-m that i was running. But i too have hear many people complaining about the C&L meters. Its not a bad idea to look into it. And yes the real only way to tune this engine properly will to be on a dyno so i will have to look into that as well. Thanks again everyone. i will let you know how she works out!
Dan

 

[luckythirteen13]

i ran the c&l on my car for the longest time. when i got the sc and when to the dyno tuner he said to get rid of it and get an 80mm pro-m....so i did