Lap record for a Gen 1 cup car around Road America on a yokohama is 2:11.8, the gen 2 will be about 2-3 seconds a lap faster than that depending on weather

Correction to last post, Current Lap record for Gen 1 Cup at RA is 2:11.8 and the cup 2 record around Road America is 2:11.3, both cars on Yokohamas and 1 year apart in stock cup car configuration

Weight's an obvious variable: Cup is ~1,240kg. GT2RS adds ~190kg (most customer spec cars are 1,430+).

For a Cup with about 500bhp, every 10kg is about 0.15 to 0.2s over a 2:07-2:08 lap at Shanghai F1 (featuring two long straights and multiple long, technical sweepers), with a full pro behind the wheel. That gap will be smaller with 700bhp to play with, but I still reckon weight alone to be a 2.5-3.5s penalty.

Then there are tires. What will your cup run, and what will be the expected age of those tires? Mich N-Blues are about 1.5 to 2s faster than the more common S9L and (debatably) somewhat faster than Pirelli DH for our laps here. From DH to Trofeo R was 2.5 to 3s back in my days in the 997.2 RS. That's anywhere from 2.5 to 5s, all HIGHLY dependent on the Cup's rubber choice and lap count...

Lastly, power: the 991.2 Cup has +35bhps over the 991.1 and is largely similar in all other aspects (front axle's improved but can't quantify "feel"). Full-pros shaved 1.5 to 2s in testing. With a 200bhp delta and adjusted for a 15% weight difference, I'd guess that swings the 6-9 seconds in favor of the GT3RS.

Thus my potato math goes, with -ve numbers in favor of the cup:

• Weight: -2.5 to -3.5
• Tires: -2.5 to -5.0 (biggest wildcard here)
• Power: +6.0 to +9.0

So for me it ain't entirely obvious that a 991.1 Cup will smoke the the GT2RS at RA. Quite the contrary, unless it's got fresh soft rubber I think the two cars will be within 2s of each other for the same pro.

Enough of geek math/conjectures already, show us pics when you get to the test and tell us the darn results already :burnout:

I am very happy to see that this thread has sparked both debate and enthusiasm which I had hoped it would!!. I like the comment about " no more stitching discussions" LOL time to have some fun with these cars!!!

Bryan is the best candidate to test the cars and while I appreciate all the advice on telemetry and Cup Car selection, I am working with what I have. Should someone be at the track with 2 VBoxes to install I am happy to oblige.

At Road America with plenty of high speed turns, my vote goes for the GT3 Cup (on Michelin stock slicks) beating the GT2RS (on MPSC2-R) by at least 6 seconds per lap.

Very cool comparison.....looking forward to the results.
Just a few thoughts....
-Although the 2RS will have over 200 more HP/TQ, the weight and the weight transfer of the car under braking and in corners like the carousel, will definitely hinder its performance.
-We have tested so many race cars vs street cars at Thermal and although it's a much tighter track, it's the braking that kills the street cars, with a lot of that having to do with the obvious tire difference.
-Rd Am will certainly allow the 2RS to stretch it's legs but there are a lot of long brake zones and I imagine the Cup braking well over 200 ft later in turns 1, 5 and 12....
-Make sure your 2RS has a harness bar and harnesses in it, that will help Bryan go a lot quicker......while feeling a lot safer!
-Bryan will have to do his bests laps in the first 3 runs on the new tires.....or that tire will fall off.
-I'm thinking the Cup will be 5 seconds faster than the GT2RS.....

Or you can wait until this comes out!! :-)


Good luck, keep us posted!!

IMO Cups are engineered for Slicks. Why put street tires on a race car, makes no sense. The goal is to see what the difference is run "as is" is it not? Evo mag has already kinda done this btw. The tested RSR, Cup R, Cup and down the line to a street RS. interesting read.