Just wondering where the extra ponies might be . Info on the car . The car is a 95z auto . Engine fully built 383, 9:1 compression ect . Heads Lt4 cnc fully ported heads cam comp cam 276/510 .. I've never had the car dyno tuned, just a mail in tune done by Ed Wright . I had it programed with shorty header and stock rockers . Fuel system includes 42lb injectors walbro intank fuel pump, t-rex inline and a areomotive fpr . I have the vortech T-trim running 13.85 psi . The car now has hooker long tubes and 1:6 rollers . I belive a dyno tune would make a big difference ( I hope ) But besides that I am up to any suggestions
Sidenote : I am going to be doing water, alky inlection for cooling purposes .

Thanks , Ben

 

You are probably getting a ton of knock retard. A dyno tune would do you good. I can't believe anyone would put a blower on a car and then get a mail order tune. Every car is different and needs individual attention. Yes some sort of cooling for the intake charge would work wonders as well! Things gotta be hot at 13 psi.

 

I agree with the mail in tune, but when you are stationed in Clovis, NM and the nearest dyno tune is 600miles away you do what you can . I have only driven the car 3 times since I upped the boost, so i'm sure there was no damange done ect...

Ben

 

Clovis huh, I know exactly what you mean. Up until a few weeks ago, I was running an Ed Wright mail order tune in my Impala also. I managed to get it to Albuquerque when Bryan H was up there, and he fixed it right up. Even with the Mailorder tune, i dont see what could be keeping your HP levels that low. My car without the N20 puts down over 460, with a basically stock motor with forged pistons and a hotcam (not even a good choice). I think you have something out of wack, you may want to have someone look at it, if you cant find it.

 

After rereading your initial post, I would say DITCH the T-rex. The walbro 255lph pumps are better off by themselves. I run 50lb injectors and 100 shot off of a walbro intank, with a KenneBelle boost-a-pump.

When you dynoed, what was your AFR like? Are you running an FMU? My EW tune was really fat, as in 8-1 AFR. Still didnt hurt my power by more than 20-25 hp though. I would imagine you are running lean. I dont think that is NEAR enough injector for a good flowing 383 with 13psi. You may want to datalog your car, and see what your injector pulse widths look like.

 

Your set-up sounds really similar to mine. I made 550 rwhp through a non-lockup TH-350 with a Walbro intank and T-Rex, but the fuel pressure was falling off on top end.

I think your problem is timing

Obviously, you need to put it on a scanner (to watch knock retard) and wide-band (for Air/Fuel ratio). It doen't really matter if you do this on the street or dyno.

My last combo was a 9/1 355 with 12 psi boost and no intercooler. It went from 400 rwhp to 460 rwhp just by adding 8 degrees timing. There was more power in it, but the knock retard pulled out any additional timing.

Mike

 

Timing is most likley the enemy here . I ditched the fmu a while back . I just hope when all is said and done I am close to 500 rw.

Ben

 

How'd you arrive at your hp numbers? ET calculators don't work as well on blown cars. What's the altitude where you're at? The injectors sound small unless you're over 4000 ft... You need to be able to look at the power band and see what's happening. Does it make power all the way to redline? Some folks have filter/intake hose collapse that makes it fall on it's face at some point. It'd also be nice to know the LSA on that cam. Lots of blower guys like 114...

 

I know a guy back in the day that drove 12 hours to get his car dyno tuned by Ed Wright... Oh that was me 4 years ago I now do it myself.

 

I'll try to locate the dyno sheet . I do remenber that it was making max power with just 8psi then it fell on it's face . They said the 1.5 rr had something to do with that among other things .

Ben

 

I'm running 1.5 RR's and it doesn't hurt power at all depending on your valve train set-up and cam. I'm running a PCMforless tune from Bryan until I also get to the dyno but I have scanned mine with Datamaster and am getting no KR and putting down about 550rwhp with 5psi boost and am looking for 600rwhp when I can dial it in on the dyno. Like the others have said I would up the injectors, I'm running 72#ers with a converter box cause the 50's weren't enough. I aslo ditched the t-rex and just run a Walbro with a BAP

 

Sorry,you are correct about the 1.5rr, it was the valve springs they said that was giving me trouble.being I had lt4 cnc ported heads ,intake and stock springs and rockers .