Terrible video :


This may belong in the tuning section, but it will get move views here.
Build : 99 vette with stock short block. Prc stage 2.5 heads, Patrick G grinded cam ( .222/.222 .602/.602 117 ) 0ff the top of my head. Homebuilt rear mount MP-T76 turbo kit w/ a/a intercooler and no boost controller. All supporting mods, secondary fuel system good for close to 1000 hp.

Trans is a built 4l60e and a vig 3400 converter.

Tune :Afr is 11.8 with 12* of timing on 93 octane and 3 lbs of boost.

The day before I put it on the dyno i made a nice test pass at 13lbs to 80mph just to see where the boost was at on the spring combo.

On the dyno it was acting like a complete *****. Kept breaking up by 3800 rpms and 3-4 lbs of boost. Checked then replaced the plugs and wires. Both weren't to bad but replacing them wasn't an issue. Still having the same issue. Plugs then checked again abd they looked good. Gapped around .022. Made pulls in several different ways. Converter locked, unlocked, minimal load, and I'm sure a few others. Im no dyno expert by any means, but thats what I believe the tuner did. On a couple misc pulls it actually boosted to about 10 then would start breaking up. I dont think we ever got a pull much over 4k.

Before I put it in the trailer the tuner had me rip it down the street. I wacked it from a 15mph roll and it pulled good and hard to 6k and 11lbs to over 80mph. Felt good but now we're stumped. The car hasn't even seen the meth kit yet. Tuner believes it might have something to do with 3rd gear. On my test street passes I never let it go into 3rd gear where the most load will be on the engine.

Does this car not like dynos or could 3rd gear on the dyno during the pull be the problem?

The only 2 things we could come up with is weak valve springs or nasty or low trans fluid. Now that I seen it go on the street I'm kinda skeptical about the springs, but I guess it wont hurt to check..

Thx for reading. Any suggestions would be great. If something doesn't look right, theres a good chance I misunderstood the tuner due to my lack of tuning experience.

 

I dunno that I would go ripping down the street in an untuned car with boost but thats me....


as for the issues I have no answer....but if you want it moved to the tuning section let me know....good luck

 

Lol. Thx. I'll let it marinate over here for a bit... I'm done with my street pulls. especially after I seen the thread with all the nice vettes in lawns and landscaping.

 

Do you have any tuning log files and the configuration file used? If so post it up that helps a lot!!

Also dumb question but did you turn the traction control off while on the dyno?

 

That's a hell of a question. Idk if the tc was on or off. The closest I got during a pull was where I took the video. ****, I wish i would have thought of that....lol. The t/c was off for the test drives... I'll call and see if he ciuld email the dyno info.

 

T/c was off... Just called... lol
He's gonna email me the logs.

 

Ok make sure he sends the config file he used too.

 

Nothing against your tuner but I think your traction control/active handling was on. It is literally the ONLY thing that could cause it to run like that on a dyno...


If there is a problem with the car, it will usually messed up during a street pull, more than it will a dyno pull.

Did the tune look good overall on the dyno? Sounds like the A/F was okay.


Again, I am guessing that the tc was on!

 

Hey bud!! I thought the same thing but with respect to that he wouldn't have got the car out of first gear with out it breaking up. If you watch the video he went through the gears.

Edit: well I watch the video closer and now I don't know. Maybe the TC was on.


To the opening poster: you said it didn't break up like that on the street right?

 

On the street it was great, and the t/c was off. I made 2 street passes in font of his shop. I called the tuner and he said if the t/c was on the car would have never turned the roller to get the party started. Hes sure it was off. They are very experienced with corvettes and camaros. His shop his littered with them. Lol

He gonna email the logs. I'll post another longer video. The 1st pull.

 

The afr was good at 11.8 and the inj duty cycle was under 40%. With 12* of timing i'd say its pretty conservative. He even pulled a few plugs to inspect the timing mark which he said looked good. No nipped or fowled out plugs.

 

1st pull. . Pardon the commentary... lol. seemed like it was gonna be a good day.

 

Mine was the same way it would hardly turn the roller with the TC on.

However it's hard to argue the possibility of TC being mistakenly turned on or left on while strapped to the dyno considering your car pulled fine on the street.

Pending what we see in these logs, if I were you I'd go try to make another dyno pull at a different dyno (ensuring yourself that the TC is turned off) and see if it does the same thing.

Just to absolutely rule it out. Even very experienced people make mistakes. It happens.

 

Ok after watching the second video it seems safe to say the TC was off. I really don't think you would have got that far if it wasn't.


Curious to see logs.

I recognize that shop that's the same place blitzkrieg was at the last time Doug of ECS tuned his car if I recall correctly.

 

I don't know your problem.
Your tranny is weak in 3rd , they all are.
I lost 3rd on the rollers and the engine sounded like crap .
Your graph may show this as well.

I replaced with a FLT tranny and life is good.
Good luck.

 

I wasn't very specific with the trans but it was build by a local guy last year. When the car was setup for hp, it made 420 rwhp and went 11.70's. I doubt I've even made that much power throught all the pulls.

 

How is the torque Managment set?

 

I'm assuming your referring to a dyno setting ? If so I dont know.

I'm still waiting on the logs to get emailed. They were pretty busy when I left.

 

I had a Camaro with a bad verter. It would pull fine if I rolled into it but as soon as I whacked it it would run like it was missing and fall on its face. I'd def look into trans and verter.

 

Tq management is in the tune as well.