I too experienced this problem, which is the rear inside wheel lifting in the middle of turns alowing the inside wheel to spin freely making the noise you can hear.
Even on a low grip surface, the rear end generates a lot of grip, making the car lean over a lot, and lifting the rear wheel.
To solve this I used stiffer side springs, and higher cst oil in the roll shock (800), and placed a 1mm shim under the front pivot balls of the side links to alow more suspension movement without having the side links hitting against the main chassis.
My F113 also had the same issue which frustrated me to no end, because I believed the diff was coming loose during a race & losing drive out of the turns, until I changed to stiffer side springs & placing the 1mm shim under the front side link balls.
Like the Xray, the F113 has a very wide chassis, along with having the side link balls mounted too low.
Other F1 cars that have a more narrow chassis, with more space between the chassis & side links don't experience this problem as much.
*edit* If you find that the rear wants to swing out on corner exit, try changing the front caster to 6 degre's instead of 9.
Cheers
Rob.
ah, so glad this is "normal" ...the sound bothered me too. But the car seems to handle very well. So not sure how much I want to go down the path of solving this sound. But since you've laid out the steps for me and done all the hard work I may just have to start tinkering
That's one thing I noticed after I had built my car, the rear end had a lot of droop/sag in it, maybe need a spacer under the piston in the main shock to curb that.
Need to try different rebound settings as well, for I suspect this will also affect the handling too.
This too I've noticed, ...its noticeable when you lift the car off the ground ..the rear sags very easily. I notice that adjusting the main shock doesn't seem to really change the amount or rate of sag. ...BUT, my car is handling well so I personally may not disrupt that by making too many adjustments off of the stock settings.