Chibo

I ended up running a session in a heavy rain for the first time in a car today and on a particular corner that is a 100-110mph straight on the brakes into a longer sweeping double apex I found my car doing something I'd think is a little strange.
Second lap out I managed to have a ridiculous vibration / noise from the rear happen on entry that felt like the inside wheel was about to come off. It went right away the split second I got on throttle and the car acted completely normal.

After playing around for a few laps I was able to replicate it at only that same corner and it was by tipping the car into the corner without getting back on to the throttle early as I normally would in the dry. I guess the only thing I could think of is if I completely unloaded the inside wheel and it didn't want to regrip since I was in the wet on NT01s with just the center two lines left. Is this how the torsens usually react to a lift / unloading in wet conditions, have I started to see the signs of an internal diff failure, or is it something completely different? I packed it in after this session -- it drove normally on the way home and for the remainder of the session once I stopped poking at the problem.

Jub

I don't really have much valuable information to finding the root of your problem. However, I do not think it's the diff based on your description and my limited understanding of how torsen's work/react. I say this because the torsen type diffs do not have any degree of lock/torque transfer when off throttle. It would act the same as an open diff when off throttle, especially with a wheel in the air. I would start looking for loose bushings/wheel bearings/leaking shocks or anything like that. Total guess on my part, it just does not sound like behavior I would expect due to torsen issues since it occurred while off throttle.

thomsbrain

Not sure if this is what you are experiencing, but I've had cold R-comps do a weird thing at the edge of adhesion where it feels like they sort of release and catch repeatedly at a high frequency and create this big vibration and "WHOOOM" sound through the car, instead of slipping smoothly. I get it when rotating the rear of the car at a big slip angle. Seems to go away once the tires warm up and I scrub off the layer of oxidized rubber. But I'm guessing in the rain the tires would never warm up.

Chibo

That is exactly what it sounded like and felt like. I think you're right, and it does make sense.