I was reading an article in the Atlanta paper this morning that was talking about the racing CTS-Vs. It said that the race version was 59% stock or came from stock components. One of the components that it mentioned was that the diff either was the stock diff or that the diff contained stock components. How is it possible that on the street they are crapping out (to use the technical term), but that they can use it on a race track? Or is this article wrong?

It didn't say how many stock differentials

The VR differential is beefed up. It isn't just like ours and I imagine it gets torn down and rebuilt regularly.

Plus, that car only gets launched from a standstill once per race. We do it 20 or more times a day.

I was reading an article in the Atlanta paper this morning that was talking about the racing CTS-Vs. It said that the race version was 59% stock or came from stock components. One of the components that it mentioned was that the diff either was the stock diff or that the diff contained stock components. How is it possible that on the street they are crapping out (to use the technical term), but that they can use it on a race track? Or is this article wrong?


That article was probably talking about the SCCA World Challenge CTS-Vs. Here are the rules. The CTS-Vs race in the GT class:
http://www.world-challenge.com/series.php?page=carfacts
Team Website:
http://www.prattmiller.com/cts.php

If the mods have to edit out the links, here is the drivetrain rules:
"Drivetrain Modifications
Transmission and differential coolers may be added. Limited-slip differentials are permitted. One set of gear ratios and two final drive ratios, or equivalent, are permitted. If the approved set of gear ratios is other than the stock set, the stock set of ratios may also be used. Clutch design is free. Flywheel weight is free, but must be steel or aluminum, and ring gear diameter must be stock.

Grand Touring (GT): Driveshafts and halfshafts are free. Alternate transmissions may be approved on a car-by-car basis if deemed necessary. Carbon clutches are permitted."

I suspect that they change out their diffs a little more often that the typical street driver does. :D

There was an article in this month's Motor Trend compareing the Race one to the stock V, and it did mention 58% stock, and the diff did contain stock parts. One would have to imagine that they would have the resources to replace/fix at a moments notice. Plus they are running 515 hp compared to our beefy 400.

Plus they are running 515 hp compared to our beefy 400.
That is my point. I guess the fact that it works and they can replace a broken one on a moment's notice is why the use the stocker. It just seems that if the diff is the weak link and they can change 42% of the car to non-stock, it would seem they would use a beefier diff. But, I'm no engineer...

The MotorTrend article states that the race CTS-V is using a 4.11 rear end, which is not our stock 3.73 ratio. So we know that the rear end is not using stock ring/pinion gearing. The real question is what case is the race CTS-V using?