putting the 383 on the dyno today
I don't think mail order tunes are perfect, but I also know NO tuner can compensate for problems with your car.
The fuel pressure should not drop if the system is healthy your pump filter lines pressure regulator etc need to be verified. Because your fuel pressure should not drop like your does
The fuel pressure should not drop if the system is healthy your pump filter lines pressure regulator etc need to be verified. Because your fuel pressure should not drop like your does
Answer his question first.
At light cruise it should be under 40psi but at WOT over.
The regulator keeps fuel pressure steady as compared to manifold pressure. So when there is high vacuum in the manifold we see a "drop" in fuel pressure and when there is little vacuum in the manifold like at WOT we see a "rise" in pressure, because a fuel pressure gauge is referenced from atmospheric pressure. If you had one that compared to manifold vacuum it would stay steady. This is done for the computer's sake. Otherwise varying manifold pressure would be trying to "suck" extra fuel from the injectors at high vacuum.
It is really starting to sound like you got in WAY beyond your limitations here and need someone hands on to help you sort it out. sounds as if there are a lot of problems to deal with before anyone can try and tune it or dyno it any more.
so my fuel pump might be ok then? but the tune might be off? im telling you though this thing pulls very hard. i have a video of the run, but there really wasnt a graph cause it was just goin to be a test pull to see if the car would down shift. could my trans be slipping a little or something?
so my fuel pump might be ok then? but the tune might be off? im telling you though this thing pulls very hard. i have a video of the run, but there really wasnt a graph cause it was just goin to be a test pull to see if the car would down shift. could my trans be slipping a little or something?
The dyno numbers you've got so far don't say much of anything, because you've got a known issue, and didn't complete the session because of the leanout. You have a test pull, that told you there are some things to be sorted out before hitting the rollers again.
Just so we're clear, leaning out big time like that, under WOT, with a high compression motor such as yours, isn't just a lack of power issue, its going to become a lack of keeping everything in one piece issue. Follow the advice about testing the fuel pressure you've been given so far as a starting point. Come back with some more information and the knowledge here will help you hammer things down. You should look into a full time fuel pressure gauge for inside the car anyways, if you're going to run the shot of nitrous you suggest in your signature.
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Yeah the numbers are Def. Low.I Dyno'd mine on a Land and Sea Load Dyno that is known for putting out lower numbers and My 383 LE2 car did over 400.Your A/F Like everyone Else said is way to Lean,Im actually suprised it hasnt burned a hole in a piston yet.I would (Like said above) go back to the Dyno,Preferably a Different dyno and a Dynojet.Ask the guys at the shop (Nicely) maybe through them a tip
If they can log a few pulls and put a fuel pressure gauge on it while they do them.If everything is still off I.E. Air fuel and Low Numbers.Print the graph and see if they can burn a copy of the logs and write down the Fuel Pressure at Cruising and WOT.Then come back on here and post it then maybe we would have a better Idea of what is going on.Good luck
If they can log a few pulls and put a fuel pressure gauge on it while they do them.If everything is still off I.E. Air fuel and Low Numbers.Print the graph and see if they can burn a copy of the logs and write down the Fuel Pressure at Cruising and WOT.Then come back on here and post it then maybe we would have a better Idea of what is going on.Good luck 
My fuel pressure was doing the same thing at high rpms and it was my pump. The fuel pressure should never go down as the rpms go up at WOT.
A racetronix kit fixed it up. Relatively cheap and a simple install.
A racetronix kit fixed it up. Relatively cheap and a simple install.
12.5:1 compression is no joke, i hurt my motor running it on pump gas and that was with a nice 12.8:1 across the board. Just do it like me and run it on E85, does kill your gas mileage a bit though...
i havnt raced the car at all, i do plan on upgrading to a racetronix kit. if i could convert to e85 taht would be awsome but i dont have the knowledge to tune the car for it. i also have a mounted fuel presssure gauge. but im afraid to do another wot pull without changing the fuel pump.
i havnt raced the car at all, i do plan on upgrading to a racetronix kit. if i could convert to e85 taht would be awsome but i dont have the knowledge to tune the car for it. i also have a mounted fuel presssure gauge. but im afraid to do another wot pull without changing the fuel pump.
Sounds like you need to be careful with what you're doing. If you know it pulls hard and murders your friends LT1 from a roll, you've been hammering it.
Checking the fuel pressure at WOT isn't going to require standing on the throttle for 5 seconds like a dyno pull, just run it up easy into the mid-range, stand on it for a second, and see if the pressure bumps up like it should, or drops. Once you know whats going on there you can start looking at what to check next.
Actually, you can just pull the vacuum line off the regulator to simulate WOT, where the vacuum drops. I would still just give it a quick stab, you'll know right off if the pressures going in the right, or wrong direction.
i think the dyno pull is when it really went south cause now the fuel pressure is even low at idle, then drops a little when you goose it. so ive got the pump out and the new racetronix kit will be here tomorow i think.
Don't forget this one:
Sounds like you need to be careful with what you're doing. If you know it pulls hard and murders your friends LT1 from a roll, you've been hammering it.
Checking the fuel pressure at WOT isn't going to require standing on the throttle for 5 seconds like a dyno pull, just run it up easy into the mid-range, stand on it for a second, and see if the pressure bumps up like it should, or drops. Once you know whats going on there you can start looking at what to check next.
Sounds like you need to be careful with what you're doing. If you know it pulls hard and murders your friends LT1 from a roll, you've been hammering it.
Checking the fuel pressure at WOT isn't going to require standing on the throttle for 5 seconds like a dyno pull, just run it up easy into the mid-range, stand on it for a second, and see if the pressure bumps up like it should, or drops. Once you know whats going on there you can start looking at what to check next.