Is it really a Limited Slip Diff ??
 

Just had the suspension in and after getting the 86 GT Manual off the trailer turned from the road into the exhaust shop.. and lost all drive with the clutch fully out ... WTF?? was my first thought .. and then I thought that with a LSD the drive should have been shifted to the wheel under load and still driven forward..

From the outset I have to say ... while I race cars I don't know everything about everything in them.. Am I wrong for being surprised ??? On the track I can't afford to loose grip if I pick up the inside so any suggestions??

its not a clutch diff, its a torsen diff. if you have one wheel up in the air it will just be like open diff.

sorry, it is a torque multiplier diff.. but 50 x 0 is 0. so yeah.. sorry, maybe not the same sort of LSD you are expecting. but other companies make the ones u are after.

you could have put the handbrake on to apply some torque to the free wheel and that would have got the other wheel moving BTW.

Torsen = "Torque Sensing" and requires both wheels to have some level of traction or resistance, otherwise you get what Surok described. It has to do with how the orbital worm gears are loaded, if there's no pressure to push back on the worm gears, they spin.

A clutch type LSD is what you were probably expecting, where the diff has two sets of clutch plates with some preload on them. This applies initial resistance while many systems utilize a pin and wedge system that increases pressure on the plates with drive force on the big ring gear. This "wedge" helps reduce slip at low power levels via the initial preload, and strong resistance to slip at high power as the pin tries to split the wedge and compress the plates on each side with increasing force. This clutch style is more popular for motorsports, but requires more maintenance as the clutch plates wear out. It's more tunable, though. The Torsen style is maintenance free, but has some limitations.

The traction control should have kicked in and the brake on that wheel should have grabbed to give the other wheel traction..

i know the BRZ does this... (cause mine does) even if the traction control is 'disabled'

What you're describing fuddbutter sounds like VSC rather than TRC.

For the OP http://www.torsen.com/products/T-2.htm.

Running a thicker oil like Amsoil 75w-110 or Redline 75w-140 helps the Torsen LSD hook up better.

The Traction / Stability control are out of the game due to the removal of the ring sensor for the removable racing wheel.. with the cage I found it very hard to get in and out.. I am 6'2" but not fat.. the first seat with head wings had to go.. that was costly !!

So I guess I am looking for a new diff after I run it in but before the race season starts in March 13..

Thanks for the education guys..

TRD make a 1.5 mechanical LSD. Not as expensive as I thought it would be, either.

TRD Diffs are fantastic. I had a 2way TRD in my AE86.. Best money I spent on that car!@

I don't have an opinion (never having fitted an aftermarket diff) but OS Giken diffs seem to have a loyal following.

If you are going to change the diff centre then its probably worth changing the ratio at the same time. Also for the track, look at removing the rear sway bar to give you some more droop.

I've got a couple of TRD 2 way Mechanical LSD's if anyone is interested .

$NZ 1200 shipped .

Why would you want to do that? You would be upsetting f/r roll stiffness balance introducing understeer. Why would you want more droop anyway?

Asssuming it has been set up for track, the spring rates will be stiffer. Also a rear wheel drive car works much better when the wheels are on the track, especially running a torsen type diff. The Torsen is a great diff that doesnt drag horsepower like a plate type LSD does.
This is a car with limited horsepower, so every bit counts.

Rememeber a race car typically runs stiff springs with sway bars set for minor adjustments. Its not a wrx or fwd that suffers badly from understeer.

A road car typically runs fairly soft springs with large sway bars so its comfortable for passengers.

Since fitting coilovers I havent felt the need for larger sway bars.

eh...harder coils doesnt mean you can eliminate the sway bar...

Shipped to Australia?

Can't change the ratio.. it's the rules and they do check ... but thanks for the advice..
CR

About to put Super Pro 20mm front and 18mm rear.. seems to be the tuners choice on size..

Might PM you re this..

Chris R

I was of the understanding the cheaper model didn't have an LSD, only the GTS.

Only the Auto GT is an open diff.

Manual/Auto GTS is a Torsen LSD as well as the GT Manual.

GT Manuals have LSD's too.

To quote someone on the racing forum on here:

If you find the rear of the car too loose, the last thing you want is more rear bar. And with the limited droop travel you don't really want more rear bar trying to pick up on, and unload the Torsen. Just today pulling in my shop I got stopped dead when the right rear came up and there I was with no drive..... Who wants to make that worse?


What spring rates are you running on your car now? I would try swapping the front sway bar in first with the stock rear bar, then test with both new bars, then no rear bar.

This is for racing not drift?

Give it a try on the track before you spend the $$$.
I find the LSD great up until you get a rear wheel off the ground. Which I'm sure happens more often in a rally car than a track car.
I'm keeping the centre for now and will be looking for 4.9 or 5.1 gears.

Also, clutch pack LSDs can induce understeer where the torsen doesn't.

Hi Josh, I agree.
Having racing many cars with locked diffs the big disadvantage is that you can't get on the throttle too early as you tend to pick up the front and with a driving inner you understeer badly.. with these cars the advantage is driving through mid corner as they don't have the power to jump on the gas on exit..

I will run the car in.. see what times I can put in.. I have a good idea where I think it should be once I get my head around the lack of power.. no more 400rwhp !!!

It has to be kept in mind that I am running Dunlop D03 R spec tyres so grip will be good.. I think it's a matter of staying off the ripple strips.. in any case when you look at how light the arms are that's a given with these.. too many hits and they will break.. I do like the idea of the two way diff though.. budget is running out at present... :(

Yep. EMS 3 - 5 day turnaround .