I'm in the process of tuning through eprom burning. I'm trying to tune WOT using a G-tech and concentrating on a change in the mph. I use the same flat stretch of road everytime. I'm having a very hard time feather launching on these street tires. My scan tool throttle position values show that I'm finally getting it to the floor at the end of first then the tires break loose again in second, but alot one time and not so much others. My mph is varying from 106-108.5 on the same chip revision. My time varies from 13.7-14.1. How much does the 60 ft time affect the trap speed? I was hoping I could tune by mph without worrying so much about my traction problems. I think I'm going to buy some Nitto drag radials this week. I also have Spohn subframes and LCA relocation brackets in the garage, just got to have them welded in. If I improve my traction problems, would my mph increase significantly? Lastly, I know the G-tech reads high mph, but assuming I'm trapping a best of 104, what's the best time I could run?

with a 104 trap speed you coudl get intothe 12's, tht woudl require a 1.75 or better 60' though.
i have seen wheel spin lead to higher and lower mph. usually a brief chirp of the tires seems to raise it a bit. but when you spin ****less, like it sounds liek you are doing, it usually costs a lot of mph becasue the car suddenly has way less track to use as an acceleration space.

later
tim

I have to disagree on alot of wheel spin leading to less mph, from my experience working and racing at the dragstrip. Excessive wheel spin usually leads to more mph. Since the mph is just a measure of how hard your car is pulling, it usually is higher since the car earlier in its run. The faster you go, the less it "pulls". It is hard to explain, but I hope this helps. With an excellent 60' you could get into the 12.9s, though I see a lot of LS1 cars running 13.8s at 102-103. So it is all about traction.

BlueTA is right.

When you lose traction you're spinning in place (sort of) but you're still creating energy (speed) so the better you hook up the slower your MPH will be.

Example:

13.2@104 2.0 60'
13.0@103 1.8 60'