Torson T-2r

[rich grsc]

Who is using the Torson T-2 differential? I think the clutch plates in the limited slip are about worn out and due for a rebuild. I was wondering how well the Torson worked compared to limited slip differential. So any info on good or bad handling characteristics would be helpful. I know the 28 spline T-2r is hard to find and expensive, while the carbon fiber rebuild kit is about $160. So could it be worth it?

[DOHCCOBRA]

Not the Torsen, but I run the Eaton True Track in my car and love how it works. You can feel the differential moving power to where it needs to be and it really keeps the car under control. I can kick the rear end out and hold it where I want it. For these cars, I would recommend this type of differential to anyone.

[racingandfishing]

Rich, I see you have similar setup to what I am considering. Small block Ford and a Torsen IRS. I've been debating between the 3.55 and the 3.73. Any thoughts?

EDIT - I see you are considering the Torsen vs. the limited slip. Anyway, any thoughts on the rear axle ratio are appreciated.

[rich grsc]

Rich, I see you have similar setup to what I am considering. Small block Ford and a Torsen IRS. I've been debating between the 3.55 and the 3.73. Any thoughts?

EDIT - I see you are considering the Torsen vs. the limited slip. Anyway, any thoughts on the rear axle ratio are appreciated.
I have always recommended 3:55, 3:73 too low, makes 1st gear useless, and rpm too high at cruise

[Hoooper]

The overwhelming consensus on 2015+ mustang forums from guys who take their cars to tracks with corners seems to be that the T2R is much better than the stock clutch LSD. Assuming you have a viscous LSD and not a mechanical like a Salisbury style, I think the T2R should be expected to be much better.

[Jim1855]

I ran a T2 in a previous car. Bought a T2 from Forte for this build but can't comment as I'm not on the road.

No issues with the T2 in 50k miles, wouldn't do it any other way.

Gears, I ran 3.27s previously and built 3.31s for this car, but it's a 427w. I think 3.55s would be great with a 5.0, 331, 347. As rich grsc said the 3.73s just run out too fast, had 'em made the change.

Jim

[racingandfishing]

I have always recommended 3:55, 3:73 too low, makes 1st gear useless, and rpm too high at cruise

That was what I figured, thanks!

I had the 3.73 in my 2015 Mustang but a much heavier car with a 7500 rpm red line and I don't want to be turning 3500 RPM at 75 mph with the pipes right next to me.

[racingandfishing]

I ran a T2 in a previous car. Bought a T2 from Forte for this build but can't comment as I'm not on the road.

No issues with the T2 in 50k miles, wouldn't do it any other way.

Gears, I ran 3.27s previously and built 3.31s for this car, but it's a 427w. I think 3.55s would be great with a 5.0, 331, 347. As rich grsc said the 3.73s just run out too fast, had 'em made the change.

Jim

Sorry, I was typing my response to Rich when you sent this. Also, thank you!

[Derald Rice]

I have a T2, 3 link 3.55 with a 347.

Night and day difference from a Trak-Loc, the throttle can be managed a lot easier when exiting a corner.

When I made the switch ( 2011 ), the T2R's were not getting good reports because they were exploding.

I love mine, and it is at a point that I just take it for granted.

FWIW.....

I do not do any work on diff's, and when my gear guy installed it, when I had my back turned, he spun it by hand.

It sounded like a bunch of marbles in a tin can.....It really got my attention , but he got a big giggle out of it.

Once it was lubed, no problems.

[edwardb]

I've had the usual clutch type limited slip setups in my previous builds including my 20th Anniversary Roadster with a 3.55 Trak-Loc IRS. Specifically sought out a Torsen IRS for my Coupe build. While I'm generally only relatively mild street driving, I like it a lot and IMO is more stable. Especially on hard acceleration. Can't say I notice a big difference in handling or turns. But again I'm not pushing it that hard. I'd use the Torsen setup again without hesitation. My only complaint (minor...) is it is a bit noisy. Seems to be the norm and probably amplified a bit in the Coupe since it's right under the hatch floor which is open to the whole cockpit.

I'm going to defend 3.73 just a bit. Don't paint with too wide a brush. Depends on the transmission. Agree for a TKX, 3.55 is preferrable. But for a T-56 which has different ratios especially for 1st and 2nd (what I have in the Coupe) the numbers are very similar with a 3.73. Run it through a calculator (like https://www.tremec.com/calculadora.php) and you'll see what I mean.

[rich grsc]

Thanks. What I wanted, first hand information and experience.

[OB6]

I bought a 3.55 Torsen from a 2021 Mustang, and I believe those are T2R's. People seem to really like them.

[racingandfishing]

https://www.tremec.com/calculadora.php[/url]) and you'll see what I mean.

I had a Gen2 Coyote with the 3.73 in my 2015 Mustang and it was great. However, with a small block ford, I will likely lose 1500 RPM from the top end vs the Coyote. I've been using the calculator and there is not a lot of difference between the 3.55 and the 3.73 - until you bump the RPM's. Even with a T-56 I am concerned first and second will be too short. Is that valid?

[Tom Veale]

I've been using "geared" differentials on race cars and street cars since the early '90s. (Quaiffe, Torsen and Eaton Trac-Lok) and would always choose them over anything with clutches. One reason is one can use far better rear axle lubricants than what can be used with clutch type anti-slip diffs.

There are differences in how much of the torque is split to the outside and inside wheels, so that should be studied. For instance, on my 1959 Austin Healey Sprite with a Quaiffe the inside wheel in heavy cornering would lift and spin a bit with heavy throttle even as it was driving the outside wheel and the car out of the corner. If I remember correctly, it had a big ratio between driven and inside wheel torque (too much inside, too little outside wheel torque). At first it seemed weird have wheel spin until I got used to it and just kept the throttle down exiting turns. Sorry I don't remember any specifics.

My current solid axle '33 FFR street rod has the Eaton Trac-Lok differential. I've driven the car hard on "track days" and on the street. It's a nice piece of equipment. Again, I don't know what the inside/outside ratio is but I've never had any wheel spin or hop exiting corners. Also, it's been fine the few times I've driven it in the rain.

I also have 3.55:1 rear gears with a Tremec 5 speed with a tall over-drive 5th (0.67?) and a pushrod 302. It's a great highway car as I found out in June on a 2600 mile drive with the Hot Rod Power Tour.

Best wishes,
Tom

[edwardb]

I had a Gen2 Coyote with the 3.73 in my 2015 Mustang and it was great. However, with a small block ford, I will likely lose 1500 RPM from the top end vs the Coyote. I've been using the calculator and there is not a lot of difference between the 3.55 and the 3.73 - until you bump the RPM's. Even with a T-56 I am concerned first and second will be too short. Is that valid?

I can only say again it depends on the transmission. Diff ratios can't be looked at in isolation. They have to consider the engine, trans, tires, and planned use. My Coyote powered Coupe with the T-56 and 3.73 is nearly the same as my previous Coyote powered Roadster with a TKO and 3.55. Same tires and wheel sizes. This isn't a hill I'm going to die on. Just pointing out that the 3.73 has some application. At the time I built my Coupe, I wanted a Torsen and they were only available in the 3.73 center section at that time. Without taking things apart and changing things. I was pleased and a bit surprised to find with the T-56 I was planning the calculated numbers were very close to what I was familiar with and liked. Three seasons of driving have confirmed, and I love having two overdrive gears in the T-56. The Torsen is now available in other ratios, e.g. 3.55) so there are more options for sure. Of course the Torsen can be retrofitted to any ratio except the 3.15 as I understand.

Ratios FWIW:

Most common TKX: 1st: 2.87, 2nd: 1.89, 3rd: 1.28, 4th: 1.00, 5th: 0.68

The T-56 in my Coupe: 1st: 2.66, 2nd: 1.78, 3rd: 1.30, 4th: 1.00, 5th: 0.80, 6th: 0.63

[Jeff Kleiner]

I can only say again it depends on the transmission. Diff ratios can't be looked at in isolation....

Agreed 100% and I've preached this almost as many times as the power steering sermon (Right Paul ;))

The question of rear gear ratio can't be answered without having the answer to preliminary questions---most importantly what are the transmission ratios. You have to do the math; for example a 2.87 first gear with 3.73 rear nets a 10.71:1 overall reduction and a 3.27 first gear combined with a 3.55 rear gets you an 11.61 overall yet sometimes statements like "3.73 is too low" get thrown out. Really? You gotta' do the math! Same on the other end...a .68 fifth gear combined with a 3.73 results in a higher overall ratio (2.54) than a 3.55 rear with a .82 fifth (2.91). Break out your calculator and punch the numbers!

Jeff

[Hoooper]

I had a Gen2 Coyote with the 3.73 in my 2015 Mustang and it was great. However, with a small block ford, I will likely lose 1500 RPM from the top end vs the Coyote. I've been using the calculator and there is not a lot of difference between the 3.55 and the 3.73 - until you bump the RPM's. Even with a T-56 I am concerned first and second will be too short. Is that valid?

Depends on the T-56. They come in close and wide ratio. I have a close ratio and Im switching out for 3.90 gears (I also have the 0.50 6th gear, its not a standard T-56), this still works out to almost 60 mph in 1st gear for me @ 7800 rpm and under 2k rpm cruising on the freeway at 75. If you have the wide ratio or the 0.63 6th gear I think you would be better off with 3.55 or 3.73

[mwd]

Love the T2. I have had it for over 20 years in the Cobra with the 8.8 IRS and it has been great. As Jim said, I wouldn't use anything else. From a handling perspective it is almost undetectable because when it is working in the turns the outside wheel is pushing harder and helping to steer the car unlike all other non-biased diffs which effectively want to un-steer the car or push it straight. The other big advantage is that it promotes traction vs the limited slip which merely limits the tire which has already lost traction.

[rich grsc]

Thanks all for the info

[rich grsc]

These seem to be as hard to find as unicorns. :(

[racingandfishing]

I bought a 2021 3.55 torsen diff from LKQ recently and it came with the pinion spline. 2018 up doesn't even need an adapter for the drive shaft. Maybe that helps the need for a 28 spline, but not sure?

[mwd]

These seem to be as hard to find as unicorns. :(

The Eaton Truetrac 912A562 is 28-spline, and readily available:
https://www.summitracing.com/parts/dtl-912a562

It is functionally equivalent to the Torsen T2, and many would say slightly better.

[mwd]

I bought a 2021 3.55 torsen diff from LKQ recently and it came with the pinion spline. 2018 up doesn't even need an adapter for the drive shaft. Maybe that helps the need for a 28 spline, but not sure?

The 2015+ Super 8.8 is different. The factory torsen diff is a sweet find, but it is 34-spline on the axles, and I'm pretty sure you cannot retrofit it to the old 8.8 IRS case anyway even if you could manage the axle problem.

[rich grsc]

The 2015+ Super 8.8 is different. The factory torsen diff is a sweet find, but it is 34-spline on the axles, and I'm pretty sure you cannot retrofit it to the old 8.8 IRS case anyway even if you could manage the axle problem.


The Eaton Truetrac 912A562 is 28-spline, and readily available:
https://www.summitracing.com/parts/dtl-912a562

It is functionally equivalent to the Torsen T2, and many would say slightly better.

Thanks, I'll check out the Truetrac, compare it to the Torsen.
Yes, the newer Torsens are not compatible with the older T-bird/Lincoln differential cases. They are 34 spline, and I need 28, no way to swap axles. To make it even more confusing, :confused: the Torsens are readily available in 31 spline, which require an axle swap at over a 1k, and up to 2k. :mad:

[racingandfishing]

Sorry, I didn't realize Rich has the older T Bird diff.

[rich grsc]

Sorry, I didn't realize Rich has the older T Bird diff.
No big deal, I had to research to find the answers. Thanks

[Jacob McCrea]

Rich,

Any chance you want to try a TrueTrac with 3.27 gears? I have had this rebuilt differential for sale forever and would love to see it go to a new home, and am not firm on the price.

https://thefactoryfiveforum.com/showthread.php?17386-For-Sale-Ford-8-8-IRS-diff-totally-rebuilt-with-Detroit-TrueTrac-amp-3-27-gears&highlight=IRS+differential+sale

[rich grsc]

Rich,

Any chance you want to try a TrueTrac with 3.27 gears? I have had this rebuilt differential for sale forever and would love to see it go to a new home, and am not firm on the price.

https://thefactoryfiveforum.com/showthread.php?17386-For-Sale-Ford-8-8-IRS-diff-totally-rebuilt-with-Detroit-TrueTrac-amp-3-27-gears&highlight=IRS+differential+sale

Thanks, I really am happy with my aluminum case, 3:55 gear set, but do you have a price in mind? You can PM if you prefer

[Jacob McCrea]

I don't have any particular price in mind, and frankly I am not sure it makes economic sense to ship the entire differential. I'd just like to see it be put to use, but at a price that doesn't have me subsidizing someone else's hobby.

By the way I have a few hundred miles with a Torsen T2 in my coupe and my impression is the same as the above positive comments. I imagine the TrueTrac works about the same. Those T2s were getting hard to find when I bought mine 8 years or so ago and I would be surprised if you found a new one. But if you do, buy it!

[rich grsc]

I had to call Torsen to find one,:(