Posi rebuild
 

I need to replace the clutches in my 9” diff. I read somewhere that a helica diff is less likely to have oversteer, powering in or coming out of a turn, is this true? Which is recommended Truetrac, Powertrax, or should I just rebuild what I have.I like the sound of a wavetrac but don’t want to change my 28 spline axles. It’s just a fun street car that is until it gets sideways.

Quaiffe Differential is the best.

I ran a Powertrax for years with no issues. Held up to my 600#s of torque and was very easy to install. My 2¢

+1 on what Morris said.

Wavetrac makes a very nice torque biasing diff, click here => Wavetrac

Read the How it's different link on the page and also the Lifetime warranty link. I think you will be imppressed.

Thank you for your reply’s, but will any of theses diffs make a difference in the backend wanting to step out? If not I probably should just rebuild because I don’t put many miles on it.

There is a predisposition for Cobras with high-powered engines to experience the back end to 'stepping out' as you say, that is inherent in the powerful engine, light car design model that the Cobra employs and we have accentuated. It is caused by the light car and a big engine that either tries to provide too much deceleration when you lift, downshift to decelerate or too much torque for the available rear tire normal force when you stand on it. Nothing can significantly change that attribute without reducing engine power. A torque biasing differential will mitigate the phenomena; however, it will not eliminate it.

You will notice a positive difference in how the car handles with a Torque Biasing differential, but you will not eliminate the rear end's predisposition to be squirrely.

I have a Powertrax. It has been in the car for about 6 years now. Works amazing! My engine has 800 hp and it holds up fine. The case is steel versus cast iron, so it is a bit lighter than other brands.

Tru-trac helical is pretty good.

If you are in the market for a Torque Biasing differential, there are a number of different providers that can satisfy your desire for one. You should look at as many as you feel comfortable with prior to making your decision. Most are a $1K or thereabouts proposition, and you want to choose wisely. A poor choice will double the cost of the acquisition, although you might be able to sell the unwanted unit in the aftermarket.

Do not base your choice on price. For these devices, the price differences tend to be about +/- 25% from low to high, which while not insignificant, pales in comparison to selecting the wrong differential. Some units have a racing-inspired heritage, and some do not.

None will be horribly wrong. However, some will have aggravating characteristics, while others will have attractive characteristics. Pay attention to the tunability of the biasing function; it is neither magic nor automatic. One provider does offer what amounts to an automatic torque biasing preload compensation. That provider is Wavetrac. They also offer a lifetime warranty which no one else does. That said, they are also at the top of the pricing pyramid.

Be deliberate, take your time, and choose what you believe is best for your situation. Do not let price drive your decision — you will likely be unhappy if you do. Pay attention to the torque biasing technology and tunability of each unit you review.

A torque biasing differential properly matched to your car and driving style will put a smile on your face and produce a measurable improvement in your driving experience. One not so well matched will not, but it will put a dent in your wallet.

There is a radio station that will help you in your decision process, it is WIIFM. WIIFM stands for, "What's In It For Me." Make sure you get a clear answer.

As the Knight's Templar suggested to Indy as he puzzled over which grail was the real Holy Grail in the Last Crusade, 'choose wisely ...'