New Dyno and found out some of my problem

WhiteDevil said:

I got my car on the dyno today at JBA Racing to see if i can figure out why it is breaking up. On the plus side i made 253rwhp and 292rwtq with a terrible 10.5-11.4 A/F ratio. On the down side right past 5,300 power takes a huge dump im talking like making 160rwhp. They did some testing and said that it is something ignition related for sure. Like the distributor pick up or maybe the ignition module, or distributor wear causing it to wobble at higher rpms. So i will be doing some ignition work next i guess. Which one do u guys think is more likely.

253rwhp @ 5250

292rwtq @ 3900

Click to expand...

what heads are you running?

Stock E7's.

Jake

Its your heads.......your getting valve float. On the intake stroke at high RPM, it creates a hugh amount of vacum.....your stock valve springs aren't strong enought to hold the valves shut......and you lose the some compresion. Makes less horsepower......get new springs with a higher rato or buy after market heads........espeicaly with all that air comin in!!!

My dad's car had a VERY similar problem, only his occured at around 6500rpms, the car would just stop pulling like it was hitting a rev limiter, but it wasn't. He put in a new coil... it didn't help. He put in a MSD 6AL... it didn't help, he put in new valve springs... they didn't help either. He then pulled the plugs out and set the gap from .054" to .045" and WHAM... it'd pull to 7000rpms. For as easy and cheap as this is to do, its worth a shot. I'd go to .040" right off the bat and see what happens. I'd "think" you'd be OK with .054 as that is where mine is at, but then again I've heard stories like my dad's more times than I can count. Try that and see what happens. Valve float is a definite possibility too. I'm VERY surprised you made that much power with the stock heads and cam. I will say this, and I'm not saying it to take away from your numbers, but I have seen a number of dyno post from JBA's dyno that were REALLY high. Recently there was a big stink over a modular guy's numbers, he put down something like 270-280rwhp with a combo that most were getting 240rwhp out of, all he had was a few bolt-ons. Take that for what its worth. I know you are running some great times with it though, so maybe you just have some sort of freak on your hands. Most combo's like your's are in the 235-240rwhp range.