I thought with any lsd with the car off the ground if you spin 1 drive wheel the opposing wheel will spin in the same direction. Mine did not, but when I launch it looks like both rear wheels are spinning/ smoking. Should I just do a burn out and find out for sure? Is there any other way to be sure with out taking off the diff cover?

 

The wavetrack is not an lsd. It is a tbd (torque biasing differential) and does not have the ability to fully lock like an lsd which uses clutches. This is likely why you can spin one wheel be itself with both wheels off the ground.

 

Thanks for the info guess I should of done a little bit more homework before jumping to conclusions.

 

They spin together. Sorry man it seems like you got lied to. If you have a wavetrac in the rear both wheels will soon together if in the air.

 

I said likely. I have no idea as I don't know much about wavetrack but tbds don't have the ability to fully lock. I dont think wavetrack has anything in their literature that would advertise it with the ability to "fully lock". I might have missed it when I glanced at their website a while back and don't recall seeing that. I think it biases torque to a cerain degree even with one unloaded wheel (unlike traditional tbds) but does not 100% lock the rear wheels together. If it was fully locking I'm sure they would certainly advertise it as such.

 

Yeah I won't mention any names on here but the person/shop who provided the info on the car is a notorious liar and has a horrible reputation. Regardless still love the car probably will end up doing an lsd sooner than later.

 

I should email thrm on it. I think your right about 100% lock up though. It does drive torque though even when 1 wheel is completely unloaded unlike a normal torsen which is why the wavetrac works so well. It's the best diff imo for a street car both performance and cost. Clutch style is better for a straight track car.

Yep sorry to hear Joey. I can tell you that adding a wavetrac to my car compared to open rear diff running rwd is a complete game changer. It even make the car drive 100 times better with the traction control fully on. Tc doesn't cut in all the time like before and allows you to actually drive normal.

 

I wish people would stop spreading this non-sense about spinning a wheel and seeing if the other spins in the same direction. It is a worthless test in many instances. If the pinion gear is resisting the whole differential from spinning so that just the spider gears allow the wheels to spin then yes they spin opposite. But if the pinion free spins without ant resistance so the whole differential housing spin like you are going in a straight line guess what, both wheels spin in the same direction. Stop spreading non-sense folks!

I would check because a torque biasing helical type diff does not incorporate static lockup so they will not lock on the lift. So spinning opposite is normal. In fact even with the clutch type diffs the spin test is a joke. It only tells you if you have static lockup which not every clutch type diff incorporates so that isn't even necessarily a valid test. Some of the race guys run zero static preload. Which means the diff spins like an open diff on the lift. The only real way to tell is drain gear oil pull the side cover and look. Which depending on miles may be a good decision anyways. Just get new oil, and and sode cover o-ring to replace existing. This was my differential carrier bearing at 102k miles.

 

Correct. I did not think a tbd including the wavetrack utilizes any type of static preload but I'm not intimately familiar with the wtrack and it may be different than a traditional tbd. A Cup/race LSD will traditionally be set up with a give or take 100lb preload. That is the amount of force one would need to exert to "break the rear wheels loose when on a lift. I'm not aware of anyone that sets up and runs a race LSD on a Porsche with zero static preload, or why they would possible want to. Even a mild OEM street LSD is set up with a minuscule preload likely for liability reasons when operating on slick surfaces as the factory likely does not want anything that would even remotely resist the cars tendency to turn under such circumstances.

 

Well I can tell you from experience that a wavetrac has enough preload tension per say that they spin in the same direction under zero load like on a lift. Biggest reason why a wavetrac is so much better than a standard torsen style is because provide torque to both wheels even under zero load and decel.

 

I have spoken to a well known gearbox builder for cup cars that has built some for zero preload. Preload does mainly two things. Sets up a starting lock value so that additional torque is not needed for lockup and lessens latency of transition between locked and not. Zero preload does not equal zero lockup. The 993 LSDs ran zero preload factory. No Belleville washers at all. But they also ran two carbon clutch plates. Not very effective. But if you ran an aggressive metal clutch setup like a guard or cup with the steel clutch plates you could run without preload. But unless you fine tune the space in the diff it may be like an on/off switch or have latency issues transitioning between locked and not. I can see a zero lockup condition being useful when you spend alot of time a low torque turns for autocross where alot of preload may fight more than help in a highly technical course. Where on a road course it may not matter because you have room to add throttle and get the car to rotate when needed. And besides, chirping tires when getting gas is overrated 😁

 

i swear by this tbd gizmo as I'm also rwd, and for reasons you stated. I've never heard anyone having driven a w'trac equipped 996tt complain about its effectiveness in any/all conditions. it also minimizes tail wag under hard braking, of that i am certain. at least as compared to running open diff

i dont think criticisms of this tbd are taking into account the changes it has from a standard style tbd. the differences appear to be genuine, and functional.

so it is written:

With a standard torque biasing gear-type LSD, if both wheels are firmly planted on the ground the diff is able to transfer power to the wheel with the most grip very effectively. But if one of the drive wheels is lifted (say during hard cornering) to the extent that it has very little load on it, the differential loses its ability to transfer power to either wheel. This is also true during the transition from acceleration to deceleration, where there is near zero torque on the axles.

to overcome this limitation, Wavetrac has developed a patent-pending device at the center of its new LSD that responds during low or zero axle-load conditions. Precisely engineered wave profiles are placed on one side gear and its mating preload hub. As the two side gears rotate relative to each other, each wave surface climbs the other, causing them to move apart.
Very quickly, this creates enough internal load within the Wavetrac to stop the zero axle-load condition, allowing the differential to transfer torque to the wheel that still has traction. The Wavetrac LSD also works well during a transition between acceleration and deceleration-the waved design of the side gears effectively eliminates the delay associated with ordinary gear-type LSDs. What this means for you as a driver is that power is delivered to the wheel(s) with the most traction, providing more consistent power delivery and more predictable handling.

 

I will be pulling the side cover to be 100% sure.