Torsen rear diff

[SCCA Stang]

hey guys... wondering if anyone has any experience that they would like to share with me about torsen rear diffs... specificly the Torsen T2R for the Mustang?

It is my understanding that the SS Camaro and the TransAm has a Torsen of some flavor, any feedback?

[dnace]

I have a torsen on the s2000. not familiar with that type. Hope its like the quafe. Mine still acts like an open diff if the rear lifts. Hence my rediculous sway bar.

[RacerX11]

The stock GM Torsen that came in the LS1 cars is referred to as the "OEM T2", and is a lighter-duty, cost-reduced version of the standard Torsen T2. It has a so-so bias ratio, and wears out easily.

A standard T2 was available as an option in some SLP cars, and also aftermarket, but did not give you any advantage over the OEM T2 other than slightly stonger gears and case. The bias ratio was the same.

The T2R aftermarket diff has a higher bias ratio, and gear preload to eliminate the open diff behavior when one wheel comes off the ground (which every gear-type diff will do if it does not have any preload).

I have been running a T2R in my '99 Z28 for ~5 years, and I love it. It makes the car very predictable to drive, and easy to control the rear end sliding under power. It was a noticable improvement over the worn-out OEM Torsen.

I have read some people on autocross forums mention some failures of the T2R diffs made in the past couple years, leading them to believe the build quality isn't what it used to be. The Detroit Tru Trac seems to be getting really good reviews, with performance similar to the T2R.

Marty

[ryans88gt]

hey guys... wondering if anyone has any experience that they would like to share with me about torsen rear diffs... specificly the Torsen T2R for the Mustang?

It is my understanding that the SS Camaro and the TransAm has a Torsen of some flavor, any feedback?

I'd seriously recommend rebuilding the stock traction lock unit before spending a ton on money on a new one.

[MoeBawlz]

I agree with Ryan... I may actually know someone selling one though if you are still interested in getting one...

[SCCA Stang]

moe bawlz... PM sent.

Ryan,
I understand what you are saying but I was seriously thinking of swaping axles for 31 splines anyway and was thinking, "while I am there", the torsen T2R seems like a nice unit

[Z3papa]

My Z3 has a torsen LSD in it and while it's not a true LSD with % lockup, it's not an open diff either.

[marty]

something that i have theorized = torsen-style LSDs fight rear brake lock-up.

[SCCA Stang]

something that i have theorized = torsen-style LSDs fight rear brake lock-up.

I can see that too... i guess if one rear tire were to lock up... the torque to each side would be drasticly different and free up the locked up wheel.

[RacerX11]

What it comes down to is the torsen-style diffs are torque-biasing, whereas clutch-style diffs are speed-biasing, up until they reach the breakaway torque of the clutches.

Clutch-style are geat for straightline racing, while the torque-biasing diffs are superior for going around corners.

Marty

[haunter]

I love the T2R in the Camaro, does a pretty good job.

they dont cost that much either

[ryans88gt]

moe bawlz... PM sent.

Ryan,
I understand what you are saying but I was seriously thinking of swaping axles for 31 splines anyway and was thinking, "while I am there", the torsen T2R seems like a nice unit

$200 gets you a trac-lok out of a 03/04 cobra ready for 31 spline axles with carbon fiber clutches on ebay.

you might want to ask yourself why you are upgrading to 31 spline axles. 28 spline axles are more than enough for 400 HP at the wheels, if you are going to 31 spline axles and plan on keeping nearly stock HP (200 at the wheels) it isn't worth it and will actually slow you down from the increased rotational mass.

I'd spend the money elsewhere...but that's just me.

[SCCA Stang]

What it comes down to is the torsen-style diffs are torque-biasing, whereas clutch-style diffs are speed-biasing, up until they reach the breakaway torque of the clutches.

Clutch-style are geat for straightline racing, while the torque-biasing diffs are superior for going around corners.

Marty

this is the reason I was looking at the torsen unit...

as far as 31 splines... I hate to limit myself to weak parts when I can go strong and have a bullet proof package...

I do not plan to leave it stock... heads and a cam along with a basic rebuild (bearings and rings with a simple hone job) are in the plans for this winter.

I know that is no-where close to 400 HP, but 31 splines does make it fairly bullet proof rear end wise.

[ryans88gt]

this is the reason I was looking at the torsen unit...

as far as 31 splines... I hate to limit myself to weak parts when I can go strong and have a bullet proof package...

I do not plan to leave it stock... heads and a cam along with a basic rebuild (bearings and rings with a simple hone job) are in the plans for this winter.

I know that is no-where close to 400 HP, but 31 splines does make it fairly bullet proof rear end wise.

Total waste of money going to 31 splines...IMO
I dropped the hammer on stock 28 splines at 5000 rpms and 26 inch ET streets pulling 1.5 60 foots for many years in the 88. It still has 28 spline axles in it, but hardened ones now. The 89 put down 515 hp on 28 spline axles. If you want to redo the rear end, I'd be more worried about the C-clips than upgrading to 31 splines.

[SCCA Stang]

Total waste of money going to 31 splines...IMO
I dropped the hammer on stock 28 splines at 5000 rpms and 26 inch ET streets pulling 1.5 60 foots for many years in the 88. It still has 28 spline axles in it, but hardened ones now. The 89 put down 515 hp on 28 spline axles. If you want to redo the rear end, I'd be more worried about the C-clips than upgrading to 31 splines.

very well noted and I will take a look at that... but they do make a 28 spline Torsen T2R and I am looking into that as well...

BTW, you mentioned c clips... what goes wrong there and what can you do to fix it besides a $3000 c-clip eliminator job.

[ryans88gt]

very well noted and I will take a look at that... but they do make a 28 spline Torsen T2R and I am looking into that as well...

BTW, you mentioned c clips... what goes wrong there and what can you do to fix it besides a $3000 c-clip eliminator job.

Well, when the c clips break, the axles and wheels come out of the housing. AutoX puts more stress on the c clips. 9 inch ends are the way to go. It isn't cheap eliminating the c clips, but not $3000. You can buy a whole 8.8 with 9 inch ends and all sorts of goodies for that price.

9 inch ends for $300
http://www.currieenterprises.com/cestore/productsRE.aspx?id=1906

[SCCA Stang]

Well, when the c clips break, the axles and wheels come out of the housing. AutoX puts more stress on the c clips. 9 inch ends are the way to go. It isn't cheap eliminating the c clips, but not $3000. You can buy a whole 8.8 with 9 inch ends and all sorts of goodies for that price.

9 inch ends for $300
http://www.currieenterprises.com/cestore/productsRE.aspx?id=1906

how likely would the whole unit come "flying out"... wouldn't the axle have to get past the whole disc brake assembly first?

and 1 shop up here did recommend doing the c clip elimination and they quoted $3000.

[psssst...passedyou]

how likely would the whole unit come "flying out"... wouldn't the axle have to get past the whole disc brake assembly first?

and 1 shop up here did recommend doing the c clip elimination and they quoted $3000.

Wow, they were going to screw you then....that is a Lot of labor cost!
These are the Moser brand C-clip Eliminators. I have heard issues with Disc brakes though, extra labor needed.
93001979-2004 7.5" & 8.8" Mustangs, Capris, & Fox Body Fords (for stock axles - 1.400" seat)150/pair93331979-2004 7.5" & 8.8" Mustangs, Capris, & Fox Body Fords (for Moser Engineering axles - 1.533" seat)150/pair

[ryans88gt]

how likely would the whole unit come "flying out"... wouldn't the axle have to get past the whole disc brake assembly first?

and 1 shop up here did recommend doing the c clip elimination and they quoted $3000.

The disc brakes are only held in place by a small bracket (with 2 small bolts) which is not rated to support the entire sideways force of a car going around a auto x course.


http://www.youtube.com/watch?v=4qNmQPYu0VY&eurl=http://video.google.com/videosearch?q=broken+c+clips&hl=en&emb=0&aq=f&feature=player_embedded

http://www.streetfire.net/video/Copperhead-88-Mustang_73051.htm

BTW if you are going to do C-clip elimination, do not do the c-clip eliminators, use 9 inch ends. Much better system and they will not leak.

[SCCA Stang]

looked like someone didn;t put something together right!!!

[ryans88gt]

looked like someone didn;t put something together right!!!

Nah, that is pretty much what happens when the c-clips or any other part of the axle breaks. Axles do occasionally break, it's nice to have an axle retention mechanism when it does happen. With that said, I have never ran any C-clip eliminator type device.

[MoeBawlz]

Ive seen it happen first hand, pretty funny if you ask me, so long as your not the guy with an axle on the ground.

As for auto X/ track events, I am pretty sure that the American Iron series does not require the use of 9" ends but they recommend it. The c clip eliminators cant stand up to the side load and C clips are also not recommended due to saftey issues but are not illegal for the series.

And for 3 grand you can buy a brand new custom axle from Moser.

[SCCA Stang]

for 3 grand I can buy my car... again!!! that is what I paid for it less than 1 year ago.

[dgmiller]

I've been running the T2R for two years now, recommended by RacerX11, and it is a big improvement over the stock Torsen unit in my Camaro. In my case, when you look at the overall strength of a GM 7.5 inch rear end, the strength of the gears is the limiting factor and upgrading to 31 spline axles is IHO a waste of money for autocross. You will break the gears before you have a chance to twist or break and axle.
For a V-8 Mustang, you should have the 8.8 inch rear end which a much stronger rear end than the GM 7.5, and the axle upgade might make sense if you are going to make a lot of HP and torque. However, in autocross it isn't the primary factor. Look at some of the raw times posted by guys like Emanuel in his Subaru Legacy wagon. The Suby has less than 100 HP at the wheels and my Camaro has 300 at the wheels and Emanuel will is often very close to me or equal in raw time and 95 % of the time will beat me on index. The set up of the car and the skill of the driver are the big factors. You don't need big power to be sucessful. However, I admit it, it does increase the fun factor.
If you get more power then you run into traction porblems and end up making more suspension, wheel and tire changes to be able to use the power and then have to upgrade the brakes to be able to slow it down again It can become a viscous circle that eats money and your car turns into something that is a bear to drive on the street.
A Ford nine inch is a very strong rear end but it is also heavier and going up in unsprung weight is going to hurt you in autocross. More inerta in turning, accelerating and breaking is not what you want. If you are going to drag race the car and go for heads, cam, etc. for big power, then this makes sense. However realize than the suspension you need for drag racing will not work at all for autocross and an autocross setup will hurt weight transfer and your 60 foot times in drag racing.
I suggestst you talk to JustJim about the suspension upgrades he has made to his Mustang. I drove it in this falls grudge matches and it handles very well. It is night and day difference to the previous year when it had the stock suspension. Another person I highly recommend you talk to is Sam Strano at Strano Parts (you can get his number off his ebsirte:stranoparts.com). He is an SCCA champion for several years in a Camaro and switched to a Shelby Mustang the past two tears. He can help you a lot. Be sure you know what your goals for the car are when you talk to him (call him as he will ask you a lot of questions to be able to make the right recommendations).

[SCCA Stang]

I've been running the T2R for two years now, recommended by RacerX11, and it is a big improvement over the stock Torsen unit in my Camaro. In my case, when you look at the overall strength of a GM 7.5 inch rear end, the strength of the gears is the limiting factor and upgrading to 31 spline axles is IHO a waste of money for autocross. You will break the gears before you have a chance to twist or break and axle.
For a V-8 Mustang, you should have the 8.8 inch rear end which a much stronger rear end than the GM 7.5, and the axle upgade might make sense if you are going to make a lot of HP and torque. However, in autocross it isn't the primary factor. Look at some of the raw times posted by guys like Emanuel in his Subaru Legacy wagon. The Suby has less than 100 HP at the wheels and my Camaro has 300 at the wheels and Emanuel will is often very close to me or equal in raw time and 95 % of the time will beat me on index. The set up of the car and the skill of the driver are the big factors. You don't need big power to be sucessful. However, I admit it, it does increase the fun factor.
If you get more power then you run into traction porblems and end up making more suspension, wheel and tire changes to be able to use the power and then have to upgrade the brakes to be able to slow it down again It can become a viscous circle that eats money and your car turns into something that is a bear to drive on the street.
A Ford nine inch is a very strong rear end but it is also heavier and going up in unsprung weight is going to hurt you in autocross. More inerta in turning, accelerating and breaking is not what you want. If you are going to drag race the car and go for heads, cam, etc. for big power, then this makes sense. However realize than the suspension you need for drag racing will not work at all for autocross and an autocross setup will hurt weight transfer and your 60 foot times in drag racing.
I suggestst you talk to JustJim about the suspension upgrades he has made to his Mustang. I drove it in this falls grudge matches and it handles very well. It is night and day difference to the previous year when it had the stock suspension. Another person I highly recommend you talk to is Sam Strano at Strano Parts (you can get his number off his ebsirte:stranoparts.com). He is an SCCA champion for several years in a Camaro and switched to a Shelby Mustang the past two tears. He can help you a lot. Be sure you know what your goals for the car are when you talk to him (call him as he will ask you a lot of questions to be able to make the right recommendations).

that's good advice there... thanks!

[SCCA Stang]

Dennis,
where dod you get your Torsen unit from??? about how much did you pay, I can't seem to find one in the T2 variety for under $550 and the T2R for under $700.

[MoeBawlz]

SCCA Stang check your PMs

[MoeBawlz]

Can anyone get a hold of SCCA Stang? If you can please tell him to check the site asap as I have a deal for him on a T2R that will pass soon.

[Dan Boles]

Left him a voice mail.

[MoeBawlz]

Thanks