Reaching limits of TorSen LSD??
 

So I've had a torsen type LSD since I've been into Miatas and never had a problem with them..from drifting to drag racing (just for fun stuff) and been out on track days...but recently i've run into a "problem" with mt Torsen. Under hard cornering (exit) and when going WOT, I am getting inside wheel spin. Also, I am running Ohlins DVFs from Goodwin (12k/8k springs). I've tried raising the car up some (12.2" ride height rear) and disconnecting the rear sway bar and have not seen any difference. The only way i'm able to reproduce the symptom is when I am running on my Kumho V710s. It almost seems like I'm getting sooo much grip from the outside rear wheel when accelerating out of a tight corner and the Torsen can't handle it and spins the inside wheel instead. Is this possible? I know that Torsens must have some load/tension/torque on both wheels...and I know I am not lifting the wheel off the ground.

Is it time for me to start looking into a clutch-type LSD al-la RX-7 or other aftermarket mfgs.?

FWIW, it works just fine on the street :dunno:

I went through the same thing for awhile at Roebling. Ends up I was lifting my inside rear wheel coming out of the turn. Was driving me nuts trying to figure out what was going on. Get someone on the track to follow you and watch the car, that's what happened to me. Had a 944 guy come in the pit and asked my if I knew the wheel was seeing daylight.

Yeah...that's what i'm thinking. But that leave me with 2 large problems- Cost and Installation. Buying it really doesn't bother me, but knowing that I cannot install it and trying to find someone who knows what they are doing is the larger hurtle.

Oh.. yeah.. just looked up that OS Giken unit.... yeah.... be awhile before I have $1600 just for the proper parts to install it :(

True. Any good driveline service shop will be able to do it. Look for a place that sets up diffs for drag racers. We have several in SoCal. You may also contact OSGiken to see if they have a recommended installer in your area.

I just used Ben Herne from PuddyMod Racing to rebuild my exploded Torsen (see thread at 4th pass and "GRUNCH!" - MX-5 Miata Forum for details). He's an expert with Miata and S2000 diffs and can also do a few choice things to strengthen the assembly (cryo treatment for the gears and a solid steel sleeve to replace the factory crush sleeve).

He's in Florida and can be reached at 352-650-3763. Highly recommended to anyone who needs a diff put together.

What do you have for a front sway bar? My RB tubular bar on full stiff made a big difference with the inside wheel spin I was getting.

'm running the FM sways. I'll adjust the front to full stiff and see what happens.

I was very happen with the Tomei LSD in my AE86. They are same unit as Kaaz, but cheaper (generally) and have a less aggressive plate arrangement out of the box (more street based).

You may need a bigger bar than the FM. I'm pretty sure that the winning bar for 01+ cars the the RB 1.25 Tubular, which is even larger than the 1.125 on my 99.

See if putting the front on full stiff makes any difference, if it does, then you will probably see even better results with the RB bar.

Also, make sure you use ramps when adjusting so your not putting any preload on the front bar, although if the FM is too small already, this may be a good thing ;)

why are there 2-options for the 1.8 miata and MSM? Is it just different splines, or could other stuff be different? I ask because I have 2 3.63's and can't seem to make them fit in my pumpkin and now I'm like $900 in just in ring-gears and there is no end in sight.

I think the MSM uses different axles.
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Yes, the MSM has a larger diameter axle and a different number of splines. There is a nice comparison p[age on OS Giken's site explaining every detail of it.

Quinn- Thanks. I also have the FM adjustable end links, might there be any help in tightening them up as well?

no chance that the internal guts are different? I can't figure out why none of my stuff fits and would really like to know why.

Well, what parts do you have?

Could you please post a link to OS Giken's page? I just looked there and can't find it.

I would speculate that you can probably add some additional preload to the bar bar by going tighter on the endlinks, but I still think that changing over to a larger tubular bar is going to yield the most substantial changes.

End link adjustment has nothing to do with handling balance. The length adjustment is there for two reasons:

1. To compensate for the swaybar/control arm/subframe assembly not being symetrical. If the bar is twisted ever so slightly when the car is parked on level ground, you adjust one link to remove the preload.

2. To lower the bar so that its as close to 90° to the end link with the car parked on level ground. When lowering the car with OEM links, the bar is forced at an upward angle. This oblique angle makes the sway bar falling rate, instead of more linear. You shorten both links to bring bar closer to 90°

i can recommend the tomei technical trax as well. it feels great and seems to not wear out easily. their claim is it has largest total friction area of any aftermarket LSD, check it out.