If you have Z31 turbo CV adapters on your Z, read this!!!

I know a lot of these CV adapters have been sold for 240Z's over the years, and there has been considerable discussion revolving around flipping the cages on the CV shafts in order to prevent the CV shafts from bottoming. I believe that on a 240Z (and probably a 260 and 280 as well but I don't have them to measure on), flipping the cages doesn't get anywhere near fixing the bind issue.

What happens if the CV bottoms out? Well it's pretty much the same thing as if the stock U/Jointed halfshaft bottoms. John Coffey did a writeup on that on his website: http://www.betamotorsports.com/benchracing/R200handling.html but the quick description is this:

At this point, the [his site says driver's side here, but on the CV setup it's both sides] rear suspension will go into a bind with any compressive load and the spring rate will skyrocket to some number defined by the flexing of metal parts in the rear suspension and rear housing mounting. In addition, large stresses are being applied to the driver's side companion flange, stub axle, bearings, and bearing housing. These parts tend to fail more frequently in 240 and 260Zs equipped with a R200.

I can recall one guy (screen name mayolives on HybridZ) who destroyed his limited slip and determined that this CV issue was the cause. When you use the CV shaft as the suspension bump stop, the loads not only go into the wheel bearings and stub axle as John describes, but they're transmitted equally into the differential as well. So carrier bearings take a beating, in limited slips the side gears move in and out so they take a beating, the pinion gears in the center are forced to run on each other while under great pressure, and if the carrier bearings start to go this can cause misalignment in the ring and pinion as well.

M2 Differentials has manufactured a solution to this problem. It is a set of custom CV shafts that puts the CV right in the middle of its travel. Being in the middle of the travel is particularly important for guys running adjustable control arms or rear camber bushings, as they might want to make the arms longer or shorter, and there is room to do so without having to worry about the shafts. There is the possibility of buying just the short shaft and then using the stock driver's side shaft on the passenger side of the car, but that wouldn't allow for shortening of the control arm. The set of shafts is normally $575, price will go down to $500 per pair if we can get a group of 10 to buy, a LH shaft is $350.

Discussion that led to this product's development:

http://forums.hybridz.org/index.php/topic/100094-cv-axle-discussion/

Installation documented with very nice pictures:

http://forums.hybridz.org/index.php/topic/103391-z31-axle-swap-r200-clsd-m2-differentials/page__p__967257__hl__%2Bcv+%2Baxle+%2Bdiscussion__fromsearch__1#entry967257

Vendor thread on Hybrid Z for group buy:

http://forums.hybridz.org/index.php/topic/102798-short-z31t-cv-shafts-group-buy/