Torsen Diff help

[d-mag]

Hey Lads, I didn't want to go off topic and hi-jack the other diff thread, so....

I have a Torsen diff in my NA Turbo that (up until now) seems to have been doing it's job well.

On my last 2 track days it's been spinning only the left rear tyre (inside rear) on certain corners. These are; Turn 8 (onto the new back straight) at Winton, and on nearly every lap at Wakefield at the fish hook.

Is it normal for Torsens to do this?

[manga_blue]

Not sure, but at 175rwkw what's normal?

[flycasta]

Firstly is it a Type 1 or 2?

You need to try and keep both wheels on the ground to stop it wheel spinning. You can try and corner differently or you need to change your suspension, ie stiffen the front to stop the back end coming up. There is no preload in either the type 1 or type 2 but the type 2 can be preloaded if you really need to.

I have had to take preload out of a Guru lately for a guy that was suffering understeer because it had too much. The Guru's Torsens are different internally to the MX5 torsen but basically work on the same principal. The main thing you have to concentrate on is keeping both wheels on the ground then you wont have a problem.

[d-mag]

It sounds simplistic to just "keep both wheels on the ground", but your right. I thought I needed some new, more race orientated coilovers, now I'm positive.
Thanks man.

[flycasta]

Sorry

In your case I am sure both wheels are still touching the ground but one is so much more unloaded than the other that the torsen is sending all of the drive to the unloaded wheel. If you can keep the load on both the same or at least more load on both wheels, you wont have the problem. You can do that by waiting for the car to straighten up more before accelerating, locking up the diff or getting some adjustable suspension. Remember that if you change the car for those 2 corners it may then make the car do the same thing on other corners. Then every track is going to be different as well so the car will require more playing with to get it right for the next track. It is a very finite process to get it absolutely right but when you do it will make the car so much better across the board.

I had to take preload out of the guru because it was not understeering on turn in, it was fantastic on turn in, it was understeering as soon as the throttle was touched on the apex. Basically is was locking both rear wheels so tightly it wasn't allowing both wheels to spin slightly independently for what was left of the corner and speering the car straight ahead.

A clutch LSD is brilliant but really need a yearly/bi-yearly check to keep the preload up and working properly for race cars, in a road car that is not the case and a locked diff although it will stop unloaded wheels spinning, what you gain from stopping the wheels spinning you well and truly lose with understeer on turn in. Clutch packs can be over preloaded with breakaway they can create understeer as well.

A torsen is the best option for longevity and handling/controlabilty but the car needs to set up correctly to get the best out of it.

[lightyear]

I have the same problem. Mine is the viscous diff and had no problem untill i put the new coilovers in. Now the car has more body roll, the inside wheel is spinning. I am doing different cornering to make more of a "v" instead of a "u" shape turn on the slower corners which helps. But i will have to stiffen the front up to be more like the old coilovers.
So just the springs and shocks can make that much difference. I know i need a better diff too.

[rascal]

On my last 2 track days it's been spinning only the left rear tyre (inside rear) on certain corners. These are; Turn 8 (onto the new back straight) at Winton, and on nearly every lap at Wakefield at the fish hook.

Daz,

Mine was spinning up the inside wheel at Winton too (at 6,7,8,9, 11..) though mine was cos I dont have a LSD

However bumping up the front arb one notch helped noticeably. Stiffer front means less body roll, as well as effectively softer rear which helps drive off corners. Car was much better after that and my quickest times came after this chg..

Russ