Rayman93RX7

iTrader: (4)

heard the T2 diff is better than the FD one, few questions...

why is it better?
why not just upgrade to Kazz?
which one do you use , S4 or S5 ?
does it bolt in to FD diff mounts?

RETed

I dunno where this myth started out, but it's not true.
Most of the FC turbo LSD's die out within the first 35K to 50K miles.
Almost all the original LSD's are all dead right now.

Torsen's are superior cause they basically do not die out like clutch-type LSD's.

I prefer Cusco over KAAZ, but either or are recommended.


-Ted

peejay

Oh yes they do. They also REALLY heat up the gear oil.

RETed

So what does this have anything to do the lower maintenance if you keep up with the scheduled maintenance?
Aggressively used clutch-type LSD's need to be rebuilt almost every year or at least every other year.
I'd prefer changing diff fluids over changing clutch packs anyday...


-Ted

gnx7

iTrader: (10)

I've put over 25K miles on my 100K mile S4 T2 diff with over 350rwtq pushed thru it. This is launching on slicks off the ebrake and running 11's.

I have no signs of failure or increased wear. Never changed fluid in 3 years and used crappy organic oil with Redline posi additive.

You are wrong reTed.... the clutch unit is the preferred LSD vs. a factory Torsen. When the clutch unit dies you simply rebuild it with a new clutch pack. Torsen dies and needs replacement.

Rayman- T2 S4 unit is preferred as it is a clutch style LSD and very beefy. It will bolt in place of the FD Torsen unit in the FD housing as it accepts an 8" ring gear as well. Much cheaper alternative than a Kazz or Cusco unit.

-GNX7

Rayman93RX7

iTrader: (4)

thanks guys great feedback

RETed

This doesn't mean anything.
In fact, sometimes you can spin an open-diff like this.
Try putting one rear in water and the other on dry pavement.
Does it still spin both tires?

I worked on a Honda CRX with an H22 motor in it using an Accord transmission that was verified open diff.
We stuffed 26x9x15 slicks on it and still managed to spin both tires in the burn-out box out at Sac Raceway.

I've hung up my '87 Turbo II on a tilted driveway and got stuck.
Why?
Cause one tire was up in the air, while the other one was firmly planted.
The car had fresh diff fluid in it, so it can't be bad maintenance.
The car had 90k miles on it.
I had another 1987 Turbo II with 60k miles on it; I hung this bitch on a tilted driveway on purpose, and it got stuck also.
I've been through enough Turbo II's (other than my three) to figure out they ALL had worn-out LSD's.
Doing burnouts on identical friction surfaces left versus right is not a good test of an LSD.
Having one side on a vastly different friction surface will truly show if the LSD is good or not.


Uh, not for road racing.
Torsen diffs have the most linear lock-up characteristics of any LSD type out there.
Most road racers prefer Torsen type LSD's.


-Ted

Maxthe7man

L-i-m-i-t-e-d S-l-i-p.....Even if it was brand new, the result would have been the same. I have been stuck in mud up to my nuts enough times with Limited slips diffs , to know how much they really limit slip, new or old...
If you had a locker that would not have happened, not a good example anyway in comparison to a torsen, if the same thing happened and you had torsen, the result would have been the same, its has a torque bias effect, and 4 times 0 = 0... Thats the shitty part about torsens, if one wheel gets zero traction, the other wheel will get zero torque, its just like an open diff when one wheel is hanging. Also the very binding that makes them work, is also there weak point, bind it up with to much power and the diff carrier just splits, it doesn't matter if its a FD rear end or dana 60 with 9.75" ring gear, they simply don't take power or rather they have a definites torque limit, that is lower than other styles of diffs... But really I can see the logic in using it in a sports car, the sports car should never be in a highcentred one wheel hanging situation, but a fast response lsd should be right at home in the sports car application, till you hit the drag strip......
The only way to get a torsen to work half decently in no traction situations is to keep the parking brake on, I once had a jeep that had a torsen installed in it, going from 29" tires to 31" tires killed it , torsen stopped making the diffs for the alot of applications, that tended to used big tires, and or big power for that very reason, to make them sturdy enough , the would no longer fit inside a particular case..
Yeah the hummer uses torsens, and the army uses the hummer, so it must be good right?.. The army also has an army of mechanics....

The TII diff is a good unit, the clucth pack design is superior to the cone style(auburn) LSd that every other oem used at some point, its rebuildable, and it does last... My TII has over 200,000 km's on the clock and it's lsd works even with roughly 25,000 km's of high hp abuse, about 10,000 of that with 275's on the rear...That said though the cusco and the Kaaz have larger clutch packs than the TII diff, if you can afford it get...
But for locking diffs, it would be nice to see one of the manafactures like Lok-rite or detroit make a true locking diff case for the rx-7, or better yet, an ARB, lock'ed diff at the touch of a button, then go to open for normal driving or an arb that only locked if tire spin was detected.. Max

RX794

I'd speak to Boostn7 about this subject, he's been doing this for years.

RETed

Yes, if it was a Torsen...you're right, the Torsen wouldn't have done nothing me me.

But, these were stock clutch-type LSD's...
If they works properly, the differential in wheel speeds should've locked both left and right (rear) wheels and pulled me out.
Am I getting the design totally wrong?


-Ted

Boostn7

Ted, when it comes down to abuse with slicks or sticky tires the Torsen in the FDs don't last for crap !!!!
In my TII I had 3 years of abuse before I broke the teeth on the ring and pinion then another 2 years on a replacement with ~80k miles.

In my FD I broke my torsen 2 years ago and replaced it with 65k miles S4 LSD diff which has been trouble free and with plenty of abuse at the track.....

I see tons of them with 80-100k+ miles and they all seem to never been open.

RETed

Oh, I agree that the Torsen is not a strong as the clutch-type LSD.
I don't think the original poster mentioned drag racing specifically.

For road racing, I'd still go Torsen.
If you're a drag fiend, then go aftermarket clutch-type LSD by all means.


-Ted

Maxthe7man

Ted, a limited slip will never lock with one wheel off the ground, a locker will, but a limited slip will not... I have used just about every type of limited slip in off-road applications, and they are exactly that, limited slip, they will never have a 100% torque bias like that, both wheels need some traction to work....They are kinda useless in off-road applications for that reason, better suited to road cars though for handling in corners, lockers tend to drag one tire one when cornering, resulting in somewhat quirky handling, my truck lays a chirp evertime I turn a corner, not bad with a large tread void mud tire on pavement, but with a sticky 275 it could be interesting...Max

Marcel Burkett

I had a series 4 T2 with 80K on the clock and the LSD worked perfectly. I now have a brand new series 4 T2 diff (just he guts) installed in my FD's casing and I have no problems. just change the oil anually and use the additive.

wanklin

iTrader: (2)

Marcel, sorry to get off subject, where did you find a new s4 diff?

Marcel Burkett

Banzaitoyata .

wanklin

iTrader: (2)

I assume that they are all gone?

wanklin

iTrader: (2)

As for the subject of this thread, There have been numerous FDs retro'd with S4 LSDs and I have yet to hear of a catastrophic failure. I am not an authority on LSDs or a mechanical engineer but I believe that the zero traction/lifted wheel test would produce the same results regardless of the condition of the diff. A member who went by the user name Vosko wrote a good bit about his T2 LSD retrofit into his single turbo FD in the past; this may be of interest to those enticed enough to read this thread, just do a search for vosko's posts.

One of the advantages noted is the quietness of the T2 unit compared to the Cusco , not sure about the Kazz.

-Rob

Marcel Burkett

Don't know , you can shoot him a P.m. and find out.

paximus

iTrader: (1)

its the kaaz thats the noisy one, how is the cusco with the clunking while turning at low speed?

jspecracer7

The cusco I have doesn't "clunk" when making turns. I have sat in a kaaz equipped FD and man it was annoying.

wanklin

iTrader: (2)

I have talked to other people with cuscos which did clunk during turns.

I guess you have a defferent model.

Rayman93RX7

iTrader: (4)

Thanks for the great imput everyone, I know I have to change out the diff now I'll just add that on to my list of winter projects, if I have the money I'll probly get the Cusco-MZ but if not I'll pick up a T2 one.

rfreeman27

iTrader: (5)

What are you going to do with teh car?

i have broken 2 stockFD torsen rears drag racing (within 2 weeks) and my TII unit has been doing fine sense then

PM rotaryrx_27 he always has a few or can track them down..