BIG diff between sports and cups - the cups are soft compound semi-slicks for track use, my guess worth about 10s at the ring.
10 seconds on a course that long is probably a very conservative estimate.
The Sport Cups are track tires. Sure they're street legal, but then again all DOT-R compound race tires are, technically, when they come out of the mould. Likewise, the Kumho Ecsta V710's I raced on with the Vette, Acura, and Honda are street legal, too. They're probably good for a few thousand miles of easy street use before they're chorded. They normally last 2-3 race weekends (12-16 heat cycles) before they're junk. The Viper's tires are the same.... they're on the car from the factory because the car was intended for
track use, not street.
As far as lap times, I'd bet the difference between race tires and street tires at that course would be more than 10 seconds. I can tell you on my older Vette that was set up strictly for track use, the difference between good street tires and DOT-R race tires on the 2.1 mile course at Roebling road was 2.5-3 seconds a lap, and close to 5 full seconds at Carolina Motorsports Park, a 14 turn 2.7 mile circuit. I'm no factory test driver, but with a NASA National class championship and a SCCA Divisional championship I think I'm good enough to know the difference and get most of the good out of each set of tires.
I stand by my position: The Viper and the Vette were running on nowhere near equal footing, and given equal rubber the ZR-1 Vette would trounce the Viper. I guess that's why the Vette engineers ignore the Viper's times for comparison's sake, and focus more on Nissaan and Porsche's times. They're competing against actual street cars that are their actual competition, not factory prepped race cars that will likely never see street use nor were they intended to.
cheers.
