when they go bad what is the failure mode.....do they lock creating a solid axel or slip creating effectively an open diff?
Just interested.

they slip and one axle gets no power

I drive several times with new front tire and still the same if not accelerate you could take out hands from steering wheel and is going perfect straight. But if I hard accelerate it turn right , worn out right rear suspension ?
I have taken today my 911 S and it goes like new car under heavy acceleration, so what it could be?:confused:

Nope. Failed LSD is just a "open" diff. LSD is actually nothing than "open" diff with pack of clutches in-between.

Clutches are not the ones transmitting the power in straight line unless one wheel starts slipping.

When on boost, rear axle will squat. In his case, I suspect:

1. Uneven tire pressure
or..
2. Rear torsion bar out of index one notch
or..
3. Parking brake cable getting tightened when car squats
or..
4. Something in rear suspension is detached


Rear suspension arms have anti-squat geometry. If one arm goes up more than other, that wheel will get more toe and start to steer the car out of straight line.

I would check torsion-bar indexing and do the corner weight.

Hopefully it is the air pressure.

Sounds like this issue started after an alignment. That the alignment followed stock alignment settings except as to camber.

The 930 suspension differs from a normal 911 in sever ways (anti squat, less rear camber loss under compression, wheels extend further from the center.) As noted above, they are sensitive to alignment settings and there sport setting is different I believe than would be used on a 911.

Do you know what settings they used? What is your fender to ground measurements and what is the angle of the front tie rods relitive to the front A arms like at rest?

Rear camber effects height and corner weighting a bunch on a 930. You might try the tripod method of as a quick check on the corner balancing. Jack the car from its standard jack point. Remove the two wheels on that side. Lower to stock height all around. On the wheel side, measure to height to center of torsion bars. Put the wheels back on, go for a drive and then do the same thing on the other side. All this should be done after first checking air pressure.

Per the factory, the 930's allowable corner balance weight is less than the 911's.

Best of luck.

I just back from 300 mil trip with new rear tires (dunlop SP 9000) and... I am surprise!
No handling problem under acceleration and free of vibration. So it was tires ! Could you imagine that tires could make such problem! I had have strong side moving (right ) under heavy acc. and now my 930 drive like new car! I spent 15 minutes with old tires and they look pretty good but it must be cord damage somewhere. I am so happy that problem is gone this way.SmileWavy

Congrats!!!!!!!!!!!!!