Originally Posted by TAPOUT
The Mach V tune was unacceptable to drive. They did a tremendous job building the car, but the the tune was no where near the way it should have been. When I picked the car up from them last week, they had slightly detuned the car from the first tune, (Pulled a degree or two of timing), but on my way home in rush hour traffic, I had to restart the car over 100 times to make it home (28 miles). Every time I came to a stop, the car stalled. I did not drive the car again until I was able to take it down and have a second set of eyes look at the car. Mach V spent nearly two full days with my car on the dyno in the first go around to try to tune it. After all of the time they spent, the car wasn't right. They gave it to me, and it was pretty smooth to drive when you were balls to the wall, but it was not driveable with stalling issues that were corrected by upping the idle speed. I took delivery of the car with the first tune which was tuned to 28psi, and was the dyno chart I posted a couple pages back. I drove the car for about 500 miles pretty easy until one night I had a buddy in the car. He said he wanted to feel the power, and I launched the car from a stop sign, grabbed second and third only to see coolant squirting on my hood. We were only about 3 blocks from my house, so we drove it home and opened the hood. There was coolant all over the engine originating from the overflow container.
I went inside, and I started reading every thing that I could find relating to the problem, and it led me to believe that the head gasket was cooked. I drove the car around the block two times the next day and it appeared that the coolant would only get pushed out when the car was under boost. I took the car back to Mach V and they pulled the engine and sent it back to the machine shop. Jim Justice pulled the motor back apart after confirming the torque values of the head bolts (80 ft lbs) and he went through and checked everything. I called him and his initial conversation with me said that the head gaskets had indeed been compromised and that he suspected that there was too much temperature in the cylinders and that had caused the head gasket to go. The only times that the car was really under strain long enough for the car to get hot would have been on the dyno. The small amount of driving I had done to get to 500 miles included a nice long highway trip which was about 420 miles round trip and never really pushing the car since I had the wife and kids with me. Upon further inspection at the machine shop, Jim found that two of the wrist pins were not straight, and had to be replaced, and the heads were warped to hell and he had to take off nearly 2 thousandths to get the heads flat again. I am still up in the air as to what happened with the car to cause these problems. I have a really hard time believing that the brand new Cosworth heads would be warped out of the box. When I took the car to get a second opinion on the tune, Hybooststi was able to determine that the fuel trims were way off, and the timing was far too advanced. He downloaded the Stock ECU figures, and the injectors were set to 1250, and on the UTEC the stock injector size was set to 999 as was the injector size. Hybooststi changed the injector values to 550 and 1000 as they should have been, and the car began to idle perfectly. This is something that has not been right since the very first build 4 years ago when I bought an FP Green and had the car tuned at Turbo XS. Since then, the car has not had a sweet steady idle, and Hybooststi fixed my car's idle issues and had the car running 100 times better in less than 15 minutes from when I showed up. Immediately after fixing the injector values, he began to look at the timing values of the tune, and found it to be advanced 5-10 degrees too much. The Mach V tune had timing advanced 17-20 degrees at redline! According to the person that tuned it this go around, he feels that the tune was the cause of all of my issues. He feels the tune caused the temperature to get so hot that it warped the head from all of the dyno pulls and that Mach V was lucky it didn't blow up there, and that it waited until the first time I really pushed it to fail. That being said, I'm not sure where all the blame lies, but I know who paid for it.
With the new tune, we are running ~30 psi on pump gas. with much less timing and it just pulls and pulls. If we get some good weather tomorrow, I am going to try to get some video footage.
I'd love to have some feedback thoughts as to why a set of Cometic head gaskets that were machined to fit would fail at 500 miles with my brand new heads being warped. It was determined that the head gasket failure was on the head side, and not the block side.
i had almost this same issue happen with a build and tune a while back. after an engine build and tune, the car was great at full throttle, but would stall at every clutch-in stop or downshift. it was almost unbearable to drive the 3hr drive home. i actually called a friend to see if he could come and get me and the family because driving it was becoming a chore in any kind of traffic (and the wife was really starting to get pissed that this is the tune we got for $700
...nothing like being worried and frustrated and then having a nagging wife and screaming kids on top of that
). i had a local speed shop that had done some subies in the past do my engine build, and then got my tune done at awdtuning. shortly after the tune, i pushed my headgasket (had the same explosion of coolant every time i would get on it). upon teardown, i found the arp's only torqued to 75ftlbs, and the timing in the tune was WAY over-advanced (like e85 type timing while running 92oct)...all this while targeting 26psi of boost on a 9.7:1CR motor. now, the arp headbolts are torqued to 90ftlbs, boost is targeting 28psi, timing is almost the same as it was on the 92oct tune, but now i am running E85 (you know...the proper fuel for that timing
). everything seems to be holding strong so far with about 8000miles on the setup.
...so hopefully for you, everything works out the same. i definitely can sympathize with your situation...
i have been following this thread from day 1 so...i really hope everything works out so i can actually see some decent results from this thing