I just got the car tuned to 10psi and am putting down 307rwhp and am having problems breaking axles. This is in my vert and it does have the entire TII drivetrain. Cars puttind down twice as much power don't have this problem as bad. The first one broke in 2nd gear pulling out of the dyno shop. That was a BRAND NEW TII halfshaft assembly. Swapped that out for a used one that I new had survived high boost/rpm launches. Seemed to have solved the problem, but only for an hour. Now I need to swap in another axle, not sure which one it was this time. Last time I could physically see the boot twisted. What happens is the ball bearings in the cv are slipping inside the cage and scarring the ball bearings.

My car is pretty low, so I'm wondering if the car getting lower from squat due to acceleration is binding up the joints and causing them to rotate inside the joint. Anyone ever hear of this? The only other thing I can think of is that I got 2 defective axles from Mazda.

Opinions...

 

what rear suspension set up are you running? and what tires?

 

Tein coilovers, Racing Beat sway bar, eurathane bushings etc. The diff mount is good.
I have 245/45/17 Bridgestone Potenzas S03's. With both incidents, this happened while already rolling along. This did not happen on the dragstrip or from a standing start. Maybe wheelhop could be the culprit? I just talked to Chris at RX7.com and he was just as perplexed as I am given the circumstances.

I'm going to raise the car up 1/2" and stiffen the rear to help eliminate some squat.

Any other suggestions, comments?

 

Maybe call a CV rebuild shop & see how much angle the joint will handle before failure,
or take the broken one to them & see what they recommend.

 

damn I have snapped one on my turbo vert already and I have not even got the stock turbo off yet. Very intrested in seeing if you can get this worked out. Mine is not as low as yours though. I just have RB new vert springs that it seeing to me that it looks the same height. But maybe they need time to work in

 

Thats strange that should not be happening. Sounds like wheelhop is breaking them.

 

Have you put in the TII drivetrain to back it up?
I have and and am having this damn problem still. This should not be happening...

 

I fixed the problem...so far.
The car was too low. I raised it 1/2" all the way around and stiffened the shocks to prevent as much squat. Hopefully I raised it enough as I only have a few spare halfshafts left. I don't care about drag racing as I know this is not the optimal setup for that.
There was just to much angle in the cv's and this was the problem, along with tripling my rwhp.

 

did you readjust the camber when you dropped the car down when you were having the problems?

 

Yes I did. As a matter of fact, I had to get both the adjustable main sublink and the two adjustable lower control arm sublinks to dial out enough camber.

 

Glad to see that you got it taken care of. I"ll have to keep that in mind with my setup, as mine is pretty low also... but I guess not like yours was

-Chris

 

Wow, 307RWHP? Egad, that's gonna be a wild ride

Can't wait to see it at the track.

 

That was at 10 psi. Boost stabiligty problems prevented me from going any higher. Steve told me 360-370 rwhp @ 15-16 psi would be easy once I get that sorted out, hopefully today. I'll be up at Sears on the 22nd.