I appreciate the comments and suggestions so far.

Doing a pretty good bit of reading on merits of TBD and LSD differentials. I'd never even heard of a TBD until this week. The differences are petty interesting.

I really didn't find anything bad mentioned about the Wavetrac units, other than they are not best suited for heavy track days, do not help in deceleration and can be limited if a rear wheel lifts and loses traction. On the flip side, the TBD seems to work great for spirited road driving and autocross events. Low to no maintenance..... This could fit the bill for me, perhaps.

The Guard LSD is unquestionably a well known brand that's well built with a track record (ha) of delivering the goods. The Guard is certainly the high water mark of LSD's. I like the idea of trail braking with the deceleration lockup, but maybe not at the expense of the mid corner under steer I've read about? I'm not planning to track the car. Never say never though.....

To complicate things......... damn if Guard doesn't offer a TBD differential too......

Are some comments due to product name brand or differential type??



Those with LSD's who primarily do NOT track their cars, what ratios are you using?

I'm still pretty confused.

 

 

 

A decent well built LSD is one of the most essential methods of extracting performance from a 911. It will settle the car under braking and enable the driver to trail brake all the way to apex/rotation. Once fully rotated on the apex it will then help deploy power on exit. This is probaly less crital as it's rear engined layout provides plently of traction but it is still a decent help - especially with high BHP cars. I like to have quite a lot of lock on braking and a lot of preload. If you trail properly, you will counter any understeer that the set up of the diff may encourage so that will not be a problem. I've driven 911's with almost 100% of lock under braking and they still rotate. One of the biggest factors in the failure of many VIP guest drivers in Carrera cup was a fundamental lack of understanding of how the diff set up works in a cup car. Driven properly they are very well setted into the corner and easy to rotate. If you drive in the typical 'brake in a straight line and trail throttle to the apex the car will feel vaigue and twitchy as you attempt to rotate it on an open diff.

I definately think that if you are comfortable with trail braking, an LSD is an essential upgrade. In terms of which one? everyone will have thier own opinions but speaking from my experience of racing and testing all different types of 911's, I would not hesitate in reccommending a Guards unit. If you speak to them about your intended usage and experience, they will give you good advice on lock and pre load set up. Bear in mind that trail braking to threashold involves balancing 2 different grip threasholds at the same time - Lateral and rotational so its very challenging, but once mastered it's one of the most useful tools in a drivers armoury.