Originally Posted by CamaroZ28_LS1

though your tune seems that it wasn't dialed in, if I broke a motor the first time, I would have at least upgraded the pistons and rod bolts while the motor was out. That being said, I run 18 degree's of timing. anything over that is a bit scary.

Originally Posted by I8UR4RD

22* is lighting the fuse for sure!

$850 so he can blow my motor.....

Id grab some forged rods, pistons, and studs and ls9 gaskets for the next build provided the block is still ok.

Originally Posted by MEAN GTO

Thanks for the response, but as I've mentioned earlier in this thread, it wouldn't have been a wise choice to spend $5k in building a forged motor, just to blow that one up instead of what I spent on 4 stock pistons/rings, head gaskets, and bolts. I feel it would have been stupid to build the motor at that point, not knowing what was causing the problem-- and luckily I didn't go that route, otherwise I obviously would now be around $6k in the hole (due to a blown-up forged motor and money spent on the initial tune) instead of $1,400 or so (money spent on the initial tune, and cost of the the parts to fix my stock motor).

Originally Posted by CamaroZ28_LS1

I understand what you mean. Hope you get it all sorted out.

Originally Posted by MEAN GTO

Hi everyone! I haven't been active on the forums much over the past couple of years due to blowing the motor in my turbo GTO for the second time (back to back) after going the turbo route.

I used to have a Magnacharger, and made 508 RWHP with many passes at the track. The car was tuned by professional tuner and was running 10.9's consistantly at the drag strip. I wanted more power and had a custom twin turbo setup fabricated, had the car retuned by the same tuner, and started having problems. Immediately after getting the car back, my new, built 4L60E transmission wouldn't upshift at WOT. The tuner couldn't figure it out, and this was not an issue with the previous tune. Several weeks after the tune I was trying to narrow down why the transmission wasn't upshifting, and blew the motor during a WOT run. I tored the engine down and it was found that all 4 pistons on bank 1 had broken ring lands.

I put very low-mileage stock pistons and rings back in the engine, and before I started driving it hard at all I had someone else look at my tune. We discovered that the tranmission upshift RPM was set to 6500, and the RPM limit was also set to 6500. We lowered the upshift RPM several hundred increments and this resolved the issue.

I then took the car to the drag strip on a hot day and it performed very poorly. It had dyno'd at 639 RWHP with the new tune on the same dyno as it was previously tuned on with the Mangacharger. So 639 RWHP with the twin turbo setup, compared to the 508 RWHP it previously made when it had a Magnacharger on it, on the same dyno. With 130 more RWHP the car wouldn't budge out of 11.2's in the 1/4 mile. It just didn't have the power in that weather for some reason to overcome the ET's that I was doing with my old supercharger setup in cooler weather.

A week after the ugly day at the drag strip then engine blew during another WOT highway run. After speaking with other people familiar with tuning, I think we have pin-pointed the problem, but without pointing the issue out I would to see if you guys wouldn't mind looking at my tune file and dyno chart to see if you see what may have caused this engine to blow both times.

Please provide any feedback you can, whether you're a beginner, amateur, or pro.... I would really appreciate your input so I can have a "case" to present to the tuner if in-fact he should be responsible for the bad parameters that were created in the tuning process.

The car is a LS2 with a custom blower cam, twin 62mm turbos, and upgraded valvetrain. It does not have catalytic converters, in case that question comes up. Thank you very much in advance!

HPT file: http://www.tinyuploads.com/download/file/u82Y9t

(I couldn't simply attached the HPT file because mine is 1.42MB and the maximum upload size on here is 1.24MB).