Went to the track friday night expecting to break into the high 13's only to be disappointed with a best of 15.1...The car seemed to buck or spit right after launch and then run normal. Couldnt find anything wrong with the naked eye. Poor lighting and no electrical outlets for our light etc. Any ideas? We had a best of 14.2 with lots of tire spin last time around due to my sons inexperience with his 6 speed etc. I know we can do high 13's. Can't figure it out. We put on 2064 shortie hooker super comps. It's a 95Z28 LT1 T56 six speed with posi disc 4.10's and borg warner centerforce clutch with pro 5.0 shifter. Everything is stock except the headers and rear. Best we could get for mph was 90. We lost 8mph from last time. His reaction times were good and his 60ft times same as last. He did some awesome burnouts so I know the tires were hot. Not a lot of tire spin.Thanks for the advice and help.

 

So you lost 8mph and nearly 1sec. since the last time you went to the track?
Did you install the headers since the last time you were there?

If so, check for burnt wires. Look for any wires touching the headers and arcing. Any exhaust leaks? 90mph trap speed is low and something is wrong.

 

The headers were installed a few days before this last run. There are no burnt wires but I will check for arcing. Had a cracked hose from the TB to the pcv valve. It was split open near the TB. Also fixed the exhaust leak. Noticed a header bolt was loose. Visually checked the O2 sensors for blockage. It seems to be a loss of power. Took the car out earlier to a back road and launched it and it ran fine. Could we have fixed it with the leaks?

 

The leaks could have been the problem. If leak is bad enough, it could cause false knock, resulting in retarted timing.

The most common problem after header install is burnt plug wires. Look closely for arcing in a dark enviroment.

 

There's no arching...I'm thinking false knock as well. Disconnected the KS and it launched fine. Hooked it back up and the same. No problems. I will check again for burnt wires tho. Thanks...

 

I think I may have found the problem. At some point between putting headers in and going to the track I filled the coolant reservoir with fluid. It was the green stuff, not dexcool....I think this may have given the KS a false reading. What do you guys think?

 

No, that isn't the problem. The ks doesn't know the difference. But if you disconnected the ks and it ran the same, false knock could be your problem. If the ks gets disconnected, the pcm automatically pulls timing just in case. Safeguard in case there really is knock.

The optispark could be to blame. My car would sputter at low rpms but clear up at higher rpms. I changed the opti and all is fine.

 

We took it out for a test launch yesterday after fixing the vaccum leak etc. and tried it with the KS disconnected and then reconnected. The problem was no longer there both times. It could be the opti cuz his water pump was leaking for a few days and we changed the pump just before leaving for the track. But all seems fine now. I was told however not to mix green with orange dexcool. What does it do? I dont know how to find out for sure what the problem was. I dont have a scanner or datalogger yet. I dont want to take it to the track again without knowing. It's not a cheap trip down.