CV's are new to Rock Racers (Ultra4). Common is the larger 30 series CV's in the Independent Front Suspensions. With the larger CV and 35 spline axles, the CV can easily go to 40* and some push them 45*. This is during turning, Articulation is still in the range of 23*. Different in IFS is that you don't ("cannot" ) have plunge or turning is problematic. Problems have always been breakage and not heat (Maybe 5 years experience as rock racing with IFS is new). I have always held that axle plunge and spline lock creates the heat and also affects suspension valving.
A 934.5 will work just fine at the IFS Diff, but will not take the rigors of turning in the uprights. A 934.5 will only wheel turn a max of 30* at 18" of articulation (best case geometry, and replaced every event). A series 30 can be wheel turned to 39* with the CV angle at 45* (best case geometry) Outside of tire (40" x 14") on most of these cars are 90"+ with 4"+ backspacing. Most cars run 4000-5000lbs and 600-900hp. Most cars are holding to 18" IFS articulation because of climbing. Rears in the 24" range (double triangulated 4 bars similar to desert trucks with 500lb+ axles) .
I have GKN series 30 CV's with 33 spline stars and wanted 35 splines. RCV said that theirs would fit...but they didn't. I still have to track this issue down but not on the front burner at this time. Just FYI. Series 30 are $$$$1,200.
There are a few IRS cars in Ultra 4. Some use portal hubs and 934 CV's. The portals are about 2:1 and I don't think the CV's are doing well either. The rear IRS are a-arms so you would think that plunge would not be an issue from all that is known about IFS. Have a-arm sand cars shown any longer CV life? Of course that depends on the designers criteria of no plunge...?
Thee are also a couple unique IRS cars out there that articulate at the middle with no plunge (Joe Thompson UFO, series 30 CV). And a couple more out there in the design/build stage with minimal/no plunge as a criteria. (34.5 and series 30 CV's) Once you have actively designed a IFS, you get the IRS criteria....It is just working with A-Arms or other novel designs. These other novel designs are allowing travel to 24" with good camber, toe and plunge control .
I believe the Class 1 Buggies have moved to series 30, and surprised the sand cars have not with the high HP. May be the weight factor....but 4 seaters???
My roots are IRS Sand Jeeps since the mid 70's. But Ultra4 has captured my interest. 4X IFS/IRS for the dunes coming.....slowly as we learn.
When designing you are always worried about unintended consequences, or things you should have known from a different perspective...which is why I am here....relating and thinking. Cool thread. Ben