rear LSD diferential

[Albert]

Hello,

As some of you know a true differential is clutch-type LSD diff. I already have V8 diff but it has all the drawbacks of torsen diff. For race purposes the only way is LSD diff.

I have found so far that the only company that makes a diff that I could use in S2 is made by STaSIS Engineering. It is quite expensive and hard to fit.

Is there any other alternative ? any other company makes true clutch-type LSD diff.
(Quaife makes only torsen diffs).

Any help would be appreciated.

Albert

pic of Stasis diff

[Error404]

are you sure about Quaife? I'm ure they can do something for you but it will be expensive.
Ricardo would be able to help too but it would be VERY expensive


What is tricky fitment wise about the STaSIS LSD?
Surely you just need to press on new bearings and races into the casing and shim it properly? Or is it more complicated?

The S1 used two Torsens, maybe they found a stronger rear one from somewhere?

the onloy other thing i can think of is the RX7 - they had a torsen diff as standard AFAIK the same internally as the quattro torsen. But a lot of them upgrade to Kaaz clutch type LSDs when going upwards of 450ish bhp.... maybe you can have a machine shop adapt a plate type diff to work in your casing.... again, expensive no doubt and some pretty heavy machining i'd guess.

TBH the STaSIS one is reasonably priced in the grand scheme of all things diff.

[Albert]

I'm more IMSA style than S1.

This is what I found about IMSA driveline:

Of course, the most interesting features of Audi Quattro's is the all-wheel-drive system. The central differential was a self-locking TORSEN. The front differential was a limited-slip setup with a viscous coupling whereas the rear used a multi-plate coupling.

[repo]

I think there is a company here in Finland that can help.

Also, IMSA transmissions didn't have torsen in the middle. It was ferguson.

[Error404]

this must be the diff then... doesn;t look like a typical audi casing

[S2central.net]

WTF is a self-locking Torsen in the centre ?

How is that different from a plain old locked / welded centre diff - like I mean how can it act like a Torsen varying torque bias some of the time and then get into a situation where it locks itself up ?

I just can't visualise how that works...


So Albert - how do you find the car drives on the track with the V8 Torsen rear diff - what don't you like about it ?

I can totally see how an LSD at the front and a lockable centre would be great... just can't work out why a clutch/plate style LSD at the rear would be significantly better than Torsen LSD/ATB.

[Error404]

i think its becasue that torsen is inherantly weak and doesn't really like heat that much.

[Albert]

WTF is a self-locking Torsen in the centre ?

How is that different from a plain old locked / welded centre diff - like I mean how can it act like a Torsen varying torque bias some of the time and then get into a situation where it locks itself up ?

I just can't visualise how that works...

I think they used standard Torsen we can now find in our cars.

So Albert - how do you find the car drives on the track with the V8 Torsen rear diff - what don't you like about it ?

I can totally see how an LSD at the front and a lockable centre would be great... just can't work out why a clutch/plate style LSD at the rear would be significantly better than Torsen LSD/ATB.

It is due to the way how torsen works. In every day driving the torsen is ok, but on the race track the torsen is not working when one wheel is in the air. And on the track it is quite often to have one of the wheels in the air. When this happens there in NO power that can be transferred to the wheels.

[S2central.net]

OK - I can understand the wheel hop thing wrt pure Torsen... but are you lifting the front or rear wheels on corners - or both ?

This makes sense why multiple Torsens exist in something like S1 for loose surface action - nothing like as stiff as a pure track setup where its possible to lift wheels in certain corners... Though can the fundamental geometry of the suspension not be adjusted / improved to reduce this tendancy ? This is NOT my area of expertise though... So just kicking ideas / questions out there - hoping for good analysis and explanation from the chassis gurus...

[repo]

Guys, You are ignoring my post for some reason.

IMSA's didn't have torsen.

[S2central.net]

Repo - I heard you the first time - no worries there... Thats what got me wondering about the diff selection on the IMSA cars versus the S1...

Is that Ferguson centre LSD some form of ATB or a lockable clutch/plate type thing ?

[Albert]

Thats what got me wondering about the diff selection on the IMSA cars versus the S1...

Different surface, different driving style.

S1 was tarmac, snow and some asphalt
IMSA only track (asphalt)

[repo]

Ferguson has planetary gear that turns propshaft through viscous coupler.

So it is a way to give different percentages of power to axles. Normally 66 front 34 rear, but I am pretty sure this varied.

Ferguson required repair pretty often. Most likely after each race. Not sure about this, but afaik officially the only guy I know did this, was Kluge. Rehauling price was around 5000 eur + vat.

You can see how worn out ferguson acts, when You find notorious kovaa.com_sponsored_700hp_spaceframe_audi_shooting _flames_on_dyno_90mb.veeämvee - clip, where the car enters the straightaway after hard right hand turn, and the right front tire puffs blue on fourth gear. Too much power to the front.

[S2central.net]

5000 Euro to rebuild the diff - OMG - that is crazy...

Why not just lock up the centre diff for permanent 50:50 split - pretty sure thats how all the URs and S1 ran from the factory on whatever surface...

Add LSDs front and rear to sort out wheel lifting mid corner - right ?

[Albert]

Why not just lock up the centre diff for permanent 50:50 split - pretty sure thats how all the URs and S1 ran from the factory on whatever surface...

My friend did this experiment, torsen was welded, the car was not able to turn around on the air port The driving pleasure was close to none.