bibbetson wrote:Traction is key, however you get it. Without it there is no way to be fast. At the last AX, I ran a set of worn out RA1's for the first session. No matter how hard I tried (I have a TBD) I couldn't get under 76.5 seconds. I bolted on a set of new shaved RA1's and dropped 2+ seconds without breaking a sweat. If you are losing grip while exiting the corners, find a way to fix it and watch your times drop in a hurry. As everyone is saying here, there are lots of ways to cure the problem.
And Bill's 2 seconds is in comparing used RA1's to new RA1's (exactly my experience as well BTW), compare normal tires to DOT racing tires and the difference is more like 3 to 4 seconds. The RA1's DOT rating is 100 and thus a 2 point tire for classification purposes.
This raises a lot of questions in my mind about the relative point values of other mods besides the 2 points for an LSD, gear ratios are 6 points, brake mods are 2 points, any of which on a good day will give you only 1 to 2 seconds- the LSD probably being most effective of these choices for autocross time reduction (if not set it up too tight, where it might actually cost time).
If we had known autocross course configurations, like we have known tracks such as Buttonwillow etc., and could gear specifically for that autocross configuration, gear ratios would be an advantage for autocross. But we don't know this, and thus gears are gears in the autocross course roulette cycle. A lower R&P would generally help acceleration though.
Since most Porsche's have excellent brakes, and weight and rotating inertia is a factor, unless you have a 356 or 924 and are switching from drums to discs, adding bigger brakes are not worth 2 points for autocross- and may actually slow you down.
Nothing comes close to tires in peeling seconds off lap times, and they are way undervalued in the hierarchy of points IMHO-particularly for autocross.
