jbrennen wrote:Jad wrote:To me, the SS class is for people who just want to drive what they bought and drive every day. A small allowance was made as this 'daily driver' often has after market wheels and tires for looks. However, if you are 'building' a car to optimize it, run CC, leave SS for the regular cars.
There's definitely a challenge to seeing how fast a car can be while still remaining basically "stock"...
Here's my "built" SS-legal car (981 Cayman GTS):
Factory configuration:
1) Base 2-way seats (for less weight)
2) PDK (faster shifts)
3) PTV (limited slip diff)
4) X73 (sports suspension)
Post-factory "build":
1) RE-71R tires (because the OEM Goodyear tires couldn't handle autoX on stadium lot -- I tried but they chunked badly); they are 10mm wider than stock (245/275 instead of 235/265) because at the time I ordered them, there was no 235/265 option
2) 19-inch OEM 987 wheels (because my car as a GTS could only be ordered with 20-inch wheels -- I never wanted 20-inch to begin with, 20-inch tires are too expensive and selection too limited)
3) Alignment (because the stock alignment is all wrong for autoX and would chew up the outside shoulders of the tires)
It's also a daily driver, with over 11,000 miles in less than 14 months of ownership. I run 91 octane gasoline, have made no weight reduction changes, and have never touched the engine except for one oil change. Brakes, including fluid, are as delivered from the dealer. Suspension is as delivered from the dealer, with just alignment changes.
So there's my build. I went down on wheel size to give me more choice of affordable tires, and I changed alignment and tires because the stock alignment and tires couldn't handle the demands of autoX.
The subject of the thread was about tire rules -- I can state that the RE-71R tires are several seconds faster than the OEM Goodyear tires on an autocross course. Don't get me wrong, I'm definitely using the right tire to go fast by SS rules. But it's not because of size -- the extra 10mm width is probably inconsequential. It's because of tire compound.
If you want to keep RE-71R tires out of SS, you could exclude them specifically. There was a lot of talk in the SCCA about doing exactly that for 2016 for their Street classes. They eventually decided that if you ask the tire manufacturers to make better autocross tires that are also usable for daily driving, you shouldn't panic when the tires show up and exceed your expectations.
Your car is a good example. SS06 includes the 981 S & GTS cars.
Your factory options would add 55 performance points , 20 for suspension, 20 for limited slip and 15 for PDK. And you have another 20 points in tire width (over stock, could be as much as 40). SO that is 75-95 points over what a "stock" 981 S might have. That is at least once class and possibly 2 classes in the CC designations.
My proposal would allow for the performance options to be taken into account.
So if someone had a stock Boxster S they would run in a different SS class than yours.
And yes the compound (and pessimistic rating) is the magic, but wider will likely be faster in the same compound
Greg