smokinstorm

We have 3.15 rear gears in a Level IV RPM dif. I've been wondering for a while if switching out to 3.42's would offer a performance advantage and I got some data on this today but not exactly how you'd think. We switched to some 2" shorter rear tires to effectively change the rear gear from 3.15 with the 28's to 3.42 with the 26's. We ran some old and nearly worn out Hoosier Drag Radials so the traction wasn't there but you could tell the car was accelerating through the gears better even though the DA was 1200 feet higher than last weekend with the 28's. You would expect the higher DA to cost at the very least MPH but it ran more MPH and was pulling back time vs last week's timeslip the whole pass. Not much but it was making up ground the whole pass.

Last week 28's -200DA----------This week 26's 1000 DA
60' 1.41-------------------------60' 1.49 Tires are junk so no surprise
330' 3.84------------------------330' 3.90
660' 5.86------------------------660' 5.90
MPH 120.97---------------------MPH 122.25

I didn't discover much trying the worn out short tires other than the fact that they don't hook worth a crap and that the car likes a little more gear. Getting some Mickey Thompson Street R's in 305/45-17's and everyone swears these are the cat's meow at the track. I'll need some 3.42's to optimize their benefit because they will change the gearing back to effectively what it was when we ran the M&H's. But now I know for sure, our car likes the slight gearing change through the gears. Subtle for sure but if you add in the fact that they should not have pulled even as strong given the DA difference, I'd say the gearing change is something we need to do ASAP. We're looking for every possible performance gain so this is one stone I'm glad we did not leave unturned.