New Dyno and found out some of my problem

[WhiteDevil]

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

 

[Killer95Stang]

I know this sounds dumb.. but replace your spark plug wires before you going tearing into everything else.. I had the same symptioms.. but told myself it couldn't be my $50 Taylor wires... well, after changing out the PIP, Coil, ignition.. ect.. I went over to Autozone and picked up a set just to test it out, and low and behold, the car ran perfect, and pulled like a mofo... I was so happy, I just kept the wires...

 

[mytight95]

well i went through the pip, ign. mod., plugs, wires, cap, and rotor button before i found it was my coil. I had even bought a new fule filter, and a few other sensors, as i was putting parts on one at a time, driving a little while and then seeing what it was.



jason

 

[WhiteDevil]

Thanks for the replies. When it started doing this i had MSD wires and autolite 25 plugs. I now have new FMS wires and new Autolites gapped at .054. I have an MSD Blaster TFI coil, i tried my stock one for a while and it still does it. So those last few things are all im left with. Im pretty happy with the power its making, its amazing how much the A/F can change with the MAF. With my Pro-M 75 i had a sweet 13.5 or so all across the board. Now with the 80 it is super rich. Im gonna back the Fuel pressure down to like 40psi.

 

[S/CBlack95GT]

How many miles are on the heads?

 

[WhiteDevil]

104,234 miles. But i have new stock valve spring on em.

 

[WhiteDevil]

ttt Those numbers seem normal right? Am i a little low on torque?

 

[mo_dingo]

We start with 285ft/lbs of tq stock, right? If so, assuming 15% drivetrain loss, you gained about 50 ft/lbs of peak torque. That intake mani helped a lot!

You also gained a lot of power up top (70 HP). Very nice gains. I am very surprised at your numbers w/o touching the heads. Can you post the dyno sheet? I would love to see it.

Yeah, your a/f needs to be higher. Hopefully turning down the FP will get you to 13-13.5. That is the best place to be NA IMO.

They seem good to me. What were you hoping for?
Scott

 

[WhiteDevil]

That is what i was hoping for pretty much. Ill see if i can over to my parents house sometime soon to scan the dyno sheet.

 

[haulbalz]

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

what heads are you running?

 

[GTJake]

Stock E7's.

Jake

 

[WhiteDevil]

Stock E7's.

Jake

Yup stock E7s and stock Cam.

 

[bqd05]

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!!!

 

[Killercanary]

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.

 

[WhiteDevil]

Thanks for that advice killer!! ill probably try that tommarow or something. As for the dyno run i have made dyno runs at the dyno shop prior to my Pro-M 80mm MAF and 1.7RR on their dyno jet and i put down 249rwhp on thier dyno jet. So i dont think that theirs is too far off.