Torsen T2R Spinning Inside Tire

[Arustik]

A buddy's Boss 302 with T2R is running Pirelli P-Zeros and has the inside wheel spinning where he can barely power out of turns during autocross. I have the same issue with my stock diff:

Notice it at 0:42-0:46 - https://www.youtube.com/watch?v=WVpd_W4teQk

Notice it at 0:22-0:25 - https://www.youtube.com/watch?v=tljklbWqvYw

Have any of your guys running slicks run into the same problems with a T2R? He is looking to potentially upgrade his Torsen and I am looking to upgrade my stock diff. I will not go with Torsen if people are experiencing similar issues.

I also have diff fluid leaking onto my LR wheel, which I notice when swapping wheels out after an event.

 

[jmauld]

No LSD will work if you unload the inside tire enough. Torsens are particularly bad in that situation. But you can fix the issue with the suspension. You need to set it up where you don't lift the rear tire off the ground in those quick transitions. You'll see pictures of RWD cars lifting the inside front wheel off of the ground in transitions. While this doesn't seem optimal for handling, it does transition part of the weight from that corner to the inside rear tire, which helps to keep it on the ground and useable. Try a stiffer front bar, or a softer rear bar to see if that helps. Just realize that you may introduce another issue, while trying to fix this one.

 

[Whiskey11]

A buddy's Boss 302 with T2R is running Pirelli P-Zeros and has the inside wheel spinning where he can barely power out of turns during autocross. I have the same issue with my stock diff:

Notice it at 0:42-0:46 - https://www.youtube.com/watch?v=WVpd_W4teQk

Notice it at 0:22-0:25 - https://www.youtube.com/watch?v=tljklbWqvYw

Have any of your guys running slicks run into the same problems with a T2R? He is looking to potentially upgrade his Torsen and I am looking to upgrade my stock diff. I will not go with Torsen if people are experiencing similar issues.

I also have diff fluid leaking onto my LR wheel, which I notice when swapping wheels out after an event.

A Torsen will behave like an open diff if it gets too light. The fix for this is going to be less rear bar, more rear spring and/or more front spring more front bar. That is going to help keep that inside tire loaded better while cornering. Probably the best thing he could do, if he has coilovers, is to get rid of the rear bar entirely and compensate with rear spring rate, or run a significantly smaller rear bar since that bar is pulling weight off of the inside tire and moving it to the outside tire.

As for yours, do you have the T-lok? If so, it's probably shot and in need of clutch pack replacement. It doesn't take much to fry a T-lok with the stock clutch packs. My GT500 packs have lasted a little longer but it still isn't as good as a proper diff.

 

[Arustik]

No LSD will work if you unload the inside tire enough. Torsens are particularly bad in that situation. But you can fix the issue with the suspension. You need to set it up where you don't lift the rear tire off the ground in those quick transitions. You'll see pictures of RWD cars lifting the inside front wheel off of the ground in transitions. While this doesn't seem optimal for handling, it does transition part of the weight from that corner to the inside rear tire, which helps to keep it on the ground and useable. Try a stiffer front bar, or a softer rear bar to see if that helps. Just realize that you may introduce another issue, while trying to fix this one.

I don't think I'm lifting any tires (although it feels it) my co-driver yesterday (ex-racer) first thought the fronts were lifting, but at the end of the day confirmed (after watching my runs) said there was no lift.

A Torsen will behave like an open diff if it gets too light. The fix for this is going to be less rear bar, more rear spring and/or more front spring more front bar. That is going to help keep that inside tire loaded better while cornering. Probably the best thing he could do, if he has coilovers, is to get rid of the rear bar entirely and compensate with rear spring rate, or run a significantly smaller rear bar since that bar is pulling weight off of the inside tire and moving it to the outside tire.

As for yours, do you have the T-lok? If so, it's probably shot and in need of clutch pack replacement. It doesn't take much to fry a T-lok with the stock clutch packs. My GT500 packs have lasted a little longer but it still isn't as good as a proper diff.

He has a stock rear sway, as I do. We talked about removing the rear sway completely.

He is running ASTs and I I'm running R2s. I believe we both have 250lbs springs in the rear.

I'm going to remove my rear sway this week and put my front bar to full stiff.

I have a completely stock drivetrain/power except for intake/exhaust.

Thoughts on doing the above and then going for a Torsen or just stick with the GT500 clutch packs? There is a guy who runs a Cobra who also suggested upgraded clutch packs.

 

[csamsh]

Huh. I've never had a spinny inside wheel with my T2R, except for when I use the right pedal too much.

I did as lots of people in this thread say, and softened my rear bar, and that small change really helped track out, but in autox and on track. Changing my UCA helped a bunch too, but sphericals aren't an option if you want to stay STU/ESP legal.

I would definitely suggest the Torsen- if you're spinning with "correct" throttle application, something else is wrong, IMO.

 

[Whiskey11]

He has a stock rear sway, as I do. We talked about removing the rear sway completely.

He is running ASTs and I I'm running R2s. I believe we both have 250lbs springs in the rear.

I'm going to remove my rear sway this week and put my front bar to full stiff.

I have a completely stock drivetrain/power except for intake/exhaust.

Thoughts on doing the above and then going for a Torsen or just stick with the GT500 clutch packs? There is a guy who runs a Cobra who also suggested upgraded clutch packs.

It's entirely possible that your stock bar is too much. You can try removing it but I would wait to stiffen the front bar up until you've seen how much push you are actually encouraging by removing the stock rear bar. You may just up the front bar and see if that helps at all and keep the rear bar on. You'll have to play with things.

If you are completely stock, running R-Comps and autocrossing a lot, I'm willing to bet that no matter what you do you will still get inside wheel spin because the T-Lok is dead.

Me personally, for autocross, Torsen T2R all day long over any clutch based diff. It's open off throttle so the car will rotate and it powers the outside wheel when on power so the car can still rotate on power. With a clutch based diff there is a push on and off power because the clutch packs are resisting the differentiating that the diff needs to do to allow the car to turn. The only reason I'm running the GT500 Clutch Packs is because they were replaced under powertrain warranty by a friend who is a Ford Tech who convinced the parts guy that this was necessary to keep me from coming back. (I had already been back once before for the same "issue" the year before ).

 

[Sky Render]

Don't bother rebuilding the stock Trak-Lok. If you're going to pull the diff, upgrade to a TrueTrac or a Torsen.

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[Arustik]

Huh. I've never had a spinny inside wheel with my T2R, except for when I use the right pedal too much.

I did as lots of people in this thread say, and softened my rear bar, and that small change really helped track out, but in autox and on track. Changing my UCA helped a bunch too, but sphericals aren't an option if you want to stay STU/ESP legal.

I would definitely suggest the Torsen- if you're spinning with "correct" throttle application, something else is wrong, IMO.

Quite possible the tire is lifting on the Boss although I highly doubt it. I specifically remember powering out of a turn on full throttle maybe 20% steering input (no lifting of wheels) and the diff acting as if it's spinning.

It's entirely possible that your stock bar is too much. You can try removing it but I would wait to stiffen the front bar up until you've seen how much push you are actually encouraging by removing the stock rear bar. You may just up the front bar and see if that helps at all and keep the rear bar on. You'll have to play with things.

If you are completely stock, running R-Comps and autocrossing a lot, I'm willing to bet that no matter what you do you will still get inside wheel spin because the T-Lok is dead.

Me personally, for autocross, Torsen T2R all day long over any clutch based diff. It's open off throttle so the car will rotate and it powers the outside wheel when on power so the car can still rotate on power. With a clutch based diff there is a push on and off power because the clutch packs are resisting the differentiating that the diff needs to do to allow the car to turn. The only reason I'm running the GT500 Clutch Packs is because they were replaced under powertrain warranty by a friend who is a Ford Tech who convinced the parts guy that this was necessary to keep me from coming back. (I had already been back once before for the same "issue" the year before ).

I may try stiffening up the front bar (currently set to middle) before pulling the rear bar, although I pulled the rear bar on my E46 and that really helped rear end planting.

Don't bother rebuilding the stock Trak-Lok. If you're going to pull the diff, upgrade to a TrueTrac or a Torsen.

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Looks like the consensus is to go T2R.

 

[Sky Render]

...Or Eaton TrueTrac if you want ~90% of the Torsen's bias ratio for half the price and don't want something that will asplode if you launch it too hard.

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[Arustik]

...Or Eaton TrueTrac if you want ~90% of the Torsen's bias ratio for half the price and don't want something that will asplode if you launch it too hard.

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Interesting. Do you run it? Anyone else have opinions?

 

[csamsh]

What is the Truetrac's ratio? I thought is was 2.7-3.0, somewhere in that range.

It certainly is more affordable than a T2R or a Boss T2.

 

[Sky Render]

Interesting. Do you run it? Anyone else have opinions?

What is the Truetrac's ratio? I thought is was 2.7-3.0, somewhere in that range.

It certainly is more affordable than a T2R or a Boss T2.

Yes, I run it. Eaton claims the bias ratio is 3.5:1 when using non-synthetic 80W-90 gear oil and no friction modifier. I believe that claim based on my seat-of-the-pants measurements.

Look for an article on it in my build thread in a week or two.

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[chilema]

I also run an Eaton Truetrac but I have to say that it does suffer from inside wheel spin as well on R-comps. I've had this happen on both Hoosier A6's and the BFG R1-S' I currently use. My car is running similar spring rates to Whiskey's car, 550lb front 250lb rear, Steeda front bar (only set at medium stiffness though). I will say that the diff only does this on high grip concrete and R-comps, as I haven't had any wheel spin issue with it when racing on RS-3's or on slicks but at choppy asphalt venues. It comes with the territory of a gear type diff without preload clutch packs, if you manage to generate enough grip to lift the inside wheel, it WILL push 100% of the power to that wheel, no two ways about it. The Truetrac does make the car turn in quite well as it will unlock completely off-power but I would actually prefer some preload off-throttle as it would give more stability in transitions (such as when slaloming).

That and my co-driver astutely noted that the Truetrac can be problematic if you hit bumps that launch a drive wheel slightly off the ground (this happens far more often than most folks think), the propensity for the Truetrac to push power to the free-spinning wheel means that when that wheel comes down on the ground (or just gains full contact again) it is going to put more shock through your driveline and possibly throw the rear end in a direction you don't want it to go. Having some preload, such as with a T2R, might help mitigate this. I haven't driven one with a T2R but as far as the Truetrac is concerned but I know exactly what he meant when I hit apex berms on a road course.

Here is one of my co-driver's runs at the event last weekend when we experienced inside wheel spin on both of the right-hand hairpins. One caveat to note is that we did discover at this event that the rear left tire was rubbing the sway bar on right turns when the drivetrain shifts over, so it may have had a braking effect on that wheel which is exaggerating the load differential. We have since switched over to a reverse-mounted Whiteline rear sway bar and will report back if it helps the issue in any way.

 

[Whiskey11]

Just an FYI, the T2R is NOT preloaded... it says right on their webpage that it isn't.

 

[sholzer]

I've had this happen with my OEM T2 and known someone running a boss in ESP at the DC pro was having issues as well. They did a diff swap/upgrade to a T2R, but I'm not sure if it helped. They also believed that the OEM diff was broken. Maybe Sam can chime in since I know he helped with the swap and talked to them firsthand, I was just watching all the updates from home ha.

 

[Dubstep Shep]

Does the Boss 302 come with a T-2R? I thought that was only the FR500S that had the T-2R.

 

[sholzer]

Boss and Laguna Seca both come with a T2

 

[Dubstep Shep]

Boss and Laguna Seca both come with a T2

Right. And the FR500S has a T-2R, which is a different diff than the T-2

 

[Kenaizer]

Right. And the FR500S has a T-2R, which is a different diff than the T-2

Shep. You're doing it again, man. Haha you asked and answered your own question.


You in Houston yet?

 

[csamsh]

The Boss has its own version of T2, which is different from a regular T2. Higher bias ratio (2.7?) and twice as expensive. The T2R is different from both of those.