Drove the car to the track today. about an hour and 15 minute drive nearly all highway. i have noticed the last few times at the track that my mph drops 3 mph or more from my first pass of the day to the second and beyond. the tire psi is within 2 psi. is it possible the tranny fluid is getting so hot that i loose mph? my 1/8th mile MPH are nearly dead on as well. my 1st and 2nd runs were within 5 minutes of each other.

Built Art Carr 4L60e
B&M tranny cooler
Yank ST4000 convertor
28x9 et drags

My ETs are dead consistent only varying a few hundredths of a second.

tried to cool the car off waiting nearly an hour. only gained 1 mph back up.

here are all four passes of the day. http://www.revxtreme.com/gallery/alb...4-16%20BMP.JPG

 

do you run a tranny temp gauge?

and also.. try daisy chaining 2 b&m tranny coolers. (say, a 19,000 and a 24,000)

you might like the results

 

Could also be track prep, after alot of cars run on a track, it can start to get sloppy. Are you running it in the daytime, where the temp is getting hotter outside, or is it getting cooler?

 

A hot 4L60E could have something to do with it. Both times I've noticed that at the track (and it wasn't weather related) I had a 3-4 clutch pack go with in the next month.

 

I installed low/high speed fan switches that I kick on right after I pass the traps. If i'm hot lapping I keep them on high untill I finish the burnout. If I park I keep it running on low for awhile to keep cool air moving under the hood.

Sounds like its just getting to hot, either the motor, trans or both.