[KonigWolf]

What are you automatic guys doing when you go to the track?

How do you go about running the stock fronts with 26s in the rear? Do you do the ABS fuse pull like on the 5th gen? Is changing the tune enough to keep the car from freaking out about two different tire sizes?

Specification Sidewall Radius Diameter Circumference Revs/Mile Difference
245/40-20 3.9in 13.9in 27.7in 87.1in 728 0.0%
275/35-20 3.8in 13.8in 27.6in 86.6in 731 0.0%
295/35-18 4.1in 13.1in 26.1in 82.1in 772 -5.3%

[wnta1ss]

My suggestion would be to pull the 2 ABS fuses when you race it and just put up with the lights on the dash and the lack of power steering while you have the short rear tires on with the tall fronts.

I changed the tire revs/mile in the tune for the short tires before I even drove my car with 245/40-20 front tires and 275/40-17 rear tires. Only drove a short distance and the car did not want to go. The computer apparently got freaked out by the mismatch. By turning the nannies off (as much as you can anyway) with the ~10sec hold down of the TC button until the 'stabilitrack off' light is on in the tach, was able to drive the car. However while making a dragstrip run like this, the 'service stabilitrack' flashed on the dash and the log showed that a timing reduction occured. That's why I am suggesting to pull the fuses when you race it, to completely disable the stabilitrack.

[KonigWolf]

Thanks for the confirmation!

[cwebster]

Originally Posted by wnta1ss

My suggestion would be to pull the 2 ABS fuses when you race it and just put up with the lights on the dash and the lack of power steering while you have the short rear tires on with the tall fronts.

I changed the tire revs/mile in the tune for the short tires before I even drove my car with 245/40-20 front tires and 275/40-17 rear tires. Only drove a short distance and the car did not want to go. The computer apparently got freaked out by the mismatch. By turning the nannies off (as much as you can anyway) with the ~10sec hold down of the TC button until the 'stabilitrack off' light is on in the tach, was able to drive the car. However while making a dragstrip run like this, the 'service stabilitrack' flashed on the dash and the log showed that a timing reduction occured. That's why I am suggesting to pull the fuses when you race it, to completely disable the stabilitrack.

There must be something different about the 6th Gen SS and the ZL1 because my attempt at the ABS Fuse Pull was a complete nightmare. (See ABS Fuse Pull on 6th Gen ZL1) It was like the torque management was on a hair-trigger. Every launch resulted in immediate nose-dive and no help from the eLSD up the track either. It felt and sounded like a wounded animal. It was not any fun to drive like that.

I'm about to pull the trigger on some new meat for my 18x12 rear BC Forged wheels. The Hoosier DR2 P335/30R18 DOT slicks are 26" dia., 12" tread width, and 12 lbs lighter than my current MT Street S/S P345/35R18. They're 1.5" shorter than the MTs but just over an inch shorter than the stock wheel/rubber. Never had trouble with the slightly taller MTs. I'm just wondering if the ZL1 will see a dramatic reaction to the shorter wheel and just how much shorter does it have to be to trigger a timing retard. With all these mandatory "protections" you'd think this M6 must be pretty feeble. Maybe they should have matched this LT4 motor with a beefier gearbox.

Diameters
Stock: (691mm) 27.2"
MT: (698.7mm) 27.5" - my current DR
Hoosier: (658.2mm) 25.9" - prospective replacement DR