[Fraxum]

Originally Posted by cwebster

Thanks for chiming in. What symptoms have you seen when it gets sick? Does it just get dizzy (handling issues) or does it cough up blood (ECM intervention)?

Okay, but if I turn off Stabilitrak and Traction Control by holding down the Traction Control button for 8-sec or more (like I always do at the drag strip) it should have no effect. I gave up on these "nannies" early last year after only a few weeks at the drag strip. If these are turned off then only unpublished, always-on "protections" are active like the infamous "Manual Transmission Protection" (aka Torque Management).

Up to now I've only compared tire height on rear wheels between stock and drag radials. Here's a comparison of front to rear looking at stock GY Eagles, my current MT DRs, and my best candidate for replacement - Hoosier DOT slick. Front never changes 'cause I'm keeping the Eagle F1 G3 tires.

                              Size
Brand         Front         Rear            Difference F/R
Goodyear      285/30R20x10  305/30R20x11    
(stock F/R)   26.7" (679mm) 27.2" (691mm)   +0.5" (+12mm)
-             -             -               -
Goodyear /    285/30R20x10  345/35R18x12
MT (Current)  26.7" (679mm) 27.5" (698.7mm) +0.8" (+19.7mm)
-             -             -               -
Goodyear /    285/30R20x10  335/30R18x12
Hoosier (New) 26.7" (679mm) 25.9" (658.2mm) -0.8" (-20.8mm)

Right off the bat I see that the stock rear tires are 1/2" taller than the front. The MT DRs I've been using are 8/10" taller, which at least partially explains why my times have actually been worse with the DRs. These new Hoosiers I've been looking at are 8/10" shorter so I should be good. If there were no intervention with taller tires I wouldn't expect any issues going an equal amount shorter.

Here's another encouraging note... I went to the dealer service dept. today to order a replacement vacuum line. While I was there I got in touch with their most experienced service manager - over 35 yrs. He says there should be no intervention whatsoever from Stabilitrak, Traction Control, or ECM going with rear tires 1" to 1 1/2" shorter than the front for drag racing.

I'm going ahead with the Hoosier DOT slicks. With the slick tread and extra 1" width I should have plenty of meat to control the extra power. Maybe I'll finally see some 1.7 60-ft times. With any luck I'll have them for the next race weekend.

Thanks to all for your insights and anecdotes guys. This forum rocks!

--Cal

The symptom was the Stabilitrac light came on (Was there a chime?) and 15 second ETs will be as good as it gets. Stabilitrac has alot of tricks I think. On my 5th gen ZL1 Stabilitrac started warning me verbally with a chime on all right hand sharp curves that my steering was failing.

Then GM decided they wanted that ZL1 back. So Stabilitrac moved me into a 2016 SS. I do wish it would have waited a while so I could have picked up a CA6 M6 ZL1. But now that I own my '16 SS I don't want to flush $25K down the toilet. The SS will have to do. Maybe a Paxton in the spring so I can turn my SS into a 3/4 ZL1. But I will be getting some hairy eyeballs at home. Oh, the price we pay to be gear heads.