Can someone tell me the difference between a ET. of 12.35 @ 108 mph. and a 12.50 ET. @ 108mph. with the same car. I'm still trying to sort of my tuning issues with my car. One thing I consistently notice is even when my jetting is off for the conditions at the track, my mph. is the same. However my ET. drops off. ( That's with about 90 deg. at the track. ) What's the contributing factor to this difference? Thanks, John
I'd say it's all in the first 100ft of the pass.......car is spinning or lazy due to a less than perfect tune-up/atmospheric conditions. Most Cars I've raced have all varied 2 to 3 tenths as the air changed through th racing season. IE:Your 12.35 best was in perfect conditions and from there it wouldn't b a surprise to see the car slow up to 12.50's in the summer heat.
I agree with Gary. Check the rest of your times on your time slip. Your 60' times will be way off if you were spinning off the line. Compare all of the incremental times and you will probably discover the culprit. Another thought, do you have a high end rev limiter and if so, were you up against it. If so, you will probably get to the limiter sooner but cannot turn the tires any faster. If that is the case, start bumping the pill in the limiter by 100 each pass to see if your MPH increases. You will, at some point, reach valve float.
I'll agree with the other two. I have 4 timeslips sitting here with the same 108.96 MPH and the times range from 12.31 - 12.10......big differences in the 60 ft times. It's all about traction and how the car hooks, or doesnt! funny that we are both running 108ish and look at the difference in our times. Of course that could be a ton of different things like rear gears, tires, ect....ect.....
All else being equal (weather especially), a "rule of thumb" is that for every 0.10 gain or loss in your 60ft time, the final 1/4 mile ET will gain or lose 0.15. At least that's what applies in the ET's we run (12.0-12.3 at 108 mph). Renee, I think weight makes a difference too (I'm at 3200 lbs, w/ pencil-neck driver!) :grin: Opel John: "You will, at some point, reach valve float." ........or rod exit!:Brow:
