I usually run in the 13.6-14.0 range at anywhere from 100-102 mph. My last 2 times at the track I have only been able to trap 97 mph. My 60ft is the same and the temperature has been the same or better. I replaced my fuel filter after the first time and it showed no improvement. The car seems to run fine, no misses or anything. What could it be?? Clogged Cat??

 

Have the ability to scan it? Might be something as simple as a o2 or drivetrain problem. I've had friends whose brakes drag and when they got them fixed picked up 2-3mph in the 1/4.

 

I do have freescan and a cable. The check engine light isn't on but I'll check anyway. Whats the easiest way to tell if the brakes are dragging and if they are how do I fix it?

 

Jack it up and if the wheels don't spin easily, brakes could be dragging.

 

Would the rears spin easily as well?

 

If it's in neutral.

 

Wise guy!

 

If you've taken off the bellows for any reason make sure it is correctly seated to your TB. It can be easy to push on w/out it being seated properly.

 

Well I just checked the brakes and they are fine, don't seem to be sticking at all. Checked my air filter, its fine. I'll remove the bellows and put it back on, hopefully that is my problem. Any other ideas???

 

Securily jack the side of the car where the cat is high enough to get some clearence so you can bang on the cat w/ your fist. If you hear anything rattling around it's probably bad. However the brick inside the cat could still be held fast and just clogged. Hell I'd cut the cat off and flange a straight pipe in its place.

 

Might be a good time for just a complete tuneup. Also remeber that it may be quite a bit hotter or more humid this time out to the track. That makes a huge difference especially w/ LT1's

 

I'm gona throw a wild guess and say your getting knock/false knock Try and find someone with a cable and do a run with a scan!

 

I understand that weather makes a huge difference. I ran a 14.0 @ 100 when it was 95 degree with like 80 percent humidity. The other night when I went it was low 70's with about 65 percent humidity and I could only get a 14.2 @ 97 out of it.


I'll try datalogging it and see if I am getting a lot of knock. I have a MadZ28 tune and I thought he turned down the sensitivity on the knock sensor.

 

Another thing I thought of. I seem to have a slight leak in the passanger side exhaust manifold. When I run seafoam through the car I can see some of the smoke come out from the manifold in the engine bay. Would a leak like this cause that much of a power loss???

 

I had an exhaust leak and my times got progressivly worse as the night went on.......cooler temps and worse times (and speeds). My header gasket was blown in two though.