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Discussion Starter #1
So it's getting close to that time of year to get out in the garage and get the 'Stang ready for some track day action. Among my list of things to do are maintenance items like oil, and transmission fluid changes. I'll also be adding a Pro-M fuel pump hanger, and 3/8" return fuel line. Oh yeah, of course there is that pesky '04 Cobra rack that's been watching patiently for the past couple of years.

One of the changes I've contemplated for quite some time is a change from the Traction Loc rear to a Torsen. The differential in the car now has very few miles, and certainly quite a while away from NEEDING replacement, but I understand that a Torsen style would be better for the track. My question is whether or not the change would be something that would noticeably impact handling and/or lap time capability. Any insight on this matter would be greatly appreciated.

Car is a '95 GT with almost the full MM catalog installed, a healthy 363, Brembos, 6 speed T-56 etc.......

Jay
 

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Thank you so much for pointing me in the direction of that information.

If I'm understanding the situation correctly, the clutched, limited slip differential exacerbates understeer, the amount determined by how much torque differential is required to overcome the friction caused by the clutches. From the practical experience of having the car up on jack stands, and trying to turn one of the wheels with the car in gear, I know the force required to turn the wheels independently is considerable.

Based on the information contained in the referenced discussion, I would conclude the scenario to benefit most from the Torsen unit, used with a solid rear axle car, would be a tight, lower speed corner with moderate throttle usage.

The aforementioned discussion also tends to make a valid argument as to why an independent rear suspension with an open differential might be an excellent solution for a track car.

In any case, it appears to me that the Torsen unit should be a worthwhile addition to my combination which does exhibit a substantial amount of understeer. I'm thinking I will try this first before fitting and experimenting with a rear anti-sway bar.

Jay
 

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Jay,

Yes, the biggest improvement in handling with a Torsen over an LSD is in the rain in tight corners. The car goes from scary, to easy to control and much more predictable.

The lack of driveshaft torque creating unequal rear tire loads when used with an IRS, is the reason that many mid and high power IRS cars come with an open differential. With an IRS, the only mechanism to create unequal rear tire loads is just the lateral weight transfer from cornering. A significantly lower TBR in the differential can handle this situation.
 

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If you use no preload spring, the car could get stuck when one tire is on a very low traction surface (wet leaves, ice, etc).
That is true with any 2wd open diff vehicle right? I figure it can't be worse than an open diff truck? Rain and leaves are a possibility. Zero to 1% chance of snow or ice.

For cornering performance, between no spring, the stock spring, and the heavier F150/Cobra spring... Your comment, as well as the explanation you gave in the other thread linked leads me to think I need no spring, or at most the stock spring, but stay away from the F150 spring?
 

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Correct, it will definitely not be worse than an open diff. You can ride the brakes and the throttle at the same time. That will help increase the locking of the differential, while keeping the torque delivered to the rear tires low in low traction conditions.

Yes, stay away from the F150 spring. At most a stock spring. If you don't mind pulling the cover off, you can try it with no spring. For autox, the only time you'd have problems is if one rear tire was lifted in the air, but in that case you have a suspension problem that needs fixing. Using a differential with more locking would be a massive crutch for this situation.
 
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