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.

Since the MSM diff has larger axles could it be said that setup can handle more power? and will an aftermarket diff not work with the MSM axles? (I just got a MSM rear end)

Well, what are you going to be doing with the car?

Mostly auto-x/track days (road course) but I'm sure i'll make it out to the strip a few times and as of now I'm unsure of my power goals. I dont expect I would want anymore than 300 whp and I'm aware this diff can support that much power, I'm more concerned with the ability to swap to a cluch based diff with those axles if I desired in the future as I have heard they are superior in every way excpt possibly for auto-x and as my power levels go up I'm sure I will have less urge to auto-x.

A question I have also have about the torsen that I have never seen addressed is under a launch/burnout, will it leave 1 or 2 tiremarks? I realize it's a LSD but from what I've read it sounds like it only really does anything if youre in a corner.

Thanks

The OS-Giken S2000 LSD will install into a MSM diff. It uses the same spline as the MSM axles. I built this set up with 3.6 gears for my car.

So does that mean that any s2k dif will fit? I would assume so. This could be a good thing as I'm sure the s2k has more diff options :idea: just could be more $:crx:

Seems likely, but I have no way of knowing for sure.

I'm going to call Gary Peloquin today and see if he wants to make a planetary diff like we talked about before. My Torsen hates me in trail braking.

A Torsen will leave two marks in a straight line all day long. The only thing that can really kill one is wheel-hop. Are you a front runner at auto-x events or do them for fun? For track day (road coarse), a Torsen will work just fine. The OSG only comes into it's element when used by a skilled driver using sticky tires and isusing the car to it's limits. It won't do sqat for you otherwise.

My issue with the Torsen was only exposed with the addition of Kuho V710s being used at lower speeds as I am exiting a corner in 2nd gear. For you, I'd say just get either a 3.9 or a 3.6 gear set for the rearend and do what you're going to do. For now, for me, I'll be swapping to a tubular front sway bar, playing with the settings on the rear bar and adding downforce as those steps are much easier (and cheaper) than spending $1400-$200 on an aftermarket unit.

Does it feel like you're getting wheel hop under hard braking/trail braking? That's my other problem, I sometimes feel a bouncing/hopping sensation when trail braking, but I've been attributing this to me getting rear wheel lockup...but I'll be interested to get your opinion if the diff has anything to do with it.

edit: misread your post. Not sure about skipping/hopping on braking, my car just unloads the inside wheel.

In my car the inside wheel lifts up, stops, and the tach turns half rpm...lol. On curbing at the track the inside tire goes nuts and smokes too. My car was so flimsy that it was picking up the front, inside wheel on cambered corner exit in 4th gear, hopefully the door bars fixed that too. I'm putting a stock sway bar in or possibly removing it all together.

This. I am getting this symptom as well and have been attributing it to the rear wheel(s) locking up and slowing RPMs. Boy it's annoying as f*ck when you try to get back on the throttle and build up rpms/boost.

I tried raising the car to increase droop as well as disconnecting the sway bar, but neither yielded much change. My next step is to see what I can do to really plant the rear wheels down.

What are your spring rates? I still bet its lifting a tire with those stickies.

We put OS Giken's into the MSM. Same part number as the AP1 so yes, it seems an AP1 diff would work in an MSM. I don't think the AP1's Torsen would be much of an improvement over the OEM Torsen or Tochigi-Fuji clutch/torsen hybrid diff.

Does the AP1 have a different Torsen than the MSM? I had just assumed they were the same, but have no knowledge or info to back that up. The AP1 I believe is preloaded. Is the MSM's preloaded?

So you could do a S2k miata swap if you had the MSM shafts?

Well, that's what I did, except with an aftermarket S2K LSD instead of OEM.
Note we're talking about using the LSD only, it has to install into a miata carrier and housing.

12k/8k

Torsens are designed with different characteristics for different cars. Having and AP1 and few Miatae, I've driven the early type I, later type II and Tochigi-Fuji diffs, they all behave a bit different. The AP1 diff seems to have a higher locking ratio or lower slip threshold (locks sooner) than the Miata diffs but that's SOTP, no numbers or factual data to share.

Have you driven an MSM? Their Bosch Torsen is unique. My SOTP says it locks sooner than the Torsen II. It's been too long since I've driven a Torsen I.

Driven every version. The MSM diff is more like an AP1 diff than the N/A Miata versions, SOTP.

take the rear swaybar off, or put on a looser bar like I told you a few posts ago.

lol at still using a rear bar.

Sell me a 3.63 set for cheap.

At the last 3 autoX's I did, I diconnected the rear sway and it didn't make a difference, I think it's really a lack of droop from the Ohlons that is pulling enough weight off the inside wheel to allow it to spin/lock under trail braking. Like I said, I tried raising the ride height to get more dropp, but it didn't work...this is how I get to the idea of trying to really plant the rear. If this doesn't work, I'm selling the car :brain:

Dopplegangbang: It's your diff. I too, was having inside wheel spin in hard cornering on the track with my torsen and that was with 120whp. It didn't matter which direction I turned.

I resolved my non-stop wheel spin issues by swapping to a Cusco RS clutch type LSD.

Gary at trackdog has been having torsen wheelspin issues for a couple of years. He's swapped/removed sway bars and played with settings and ultimately ended up keeping the rear bar because he like the handling with the rear bar. Driving style and car feel obviously play a big factor, but a real diff makes a huge difference.

i could elaborate more and show video, but emilio and I know what's up.

I guess I'll call Peloquin tomorrow.

i have a s2k torsen ready to ship if anyone wants one. (ap1) great condition
$250 plus shipping

sorry not trying to threadjack. this is a reply to the op really, but anyone if he's not interested.

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I agree, my MSM acted nothing like my 95 with a torsen, the MSM would chatter when leaving stop light's and making a right turn under accel.

The brakes, manifold, torsen problems are all setup and driver specific. If your not having the problem then forget about it. By my calculations this board is costing you close to 1k-2k a month...ouch

How easy is the RS to modulate when applying throttle? 1.5 way? 2 way? I've heard of them having some understeer issues...but I guess that can be neutralized with a little different driving style.

That's the first thing that came to my mind, too.

Also try less rebound damping.

because what I want to do is spend $1100 on a differential and then have to alter my driving style due to an undesirable characteristic.

I've driven an OS Giken - it's quite impressive. It doesn't really feel like anything particularly special, except when I come out of a tight 3rd gear corner and stick 300wtq to the ground with absolutely no drama at all.

Your not going to eliminate the wheel spin with sway bar/shock adjustments.
some of these guys have been telling you the Torsen,any Torsen, has it's limits.
With sticky tires this is going to happen no matter what.
This is why Matt Andrews, Emilio , Savington , and all the track guys on real tires are using a clutch type diff.
Being able to put the power down and get out of the hole is not going to happen with a torsen. Besides , you will love your car again once you add a clutch type. It doesn't need to be the OS. But I'm sure You won't want anything less.

To be fair, the Torsen is a great diff up to about 200whp. The OSG is faster (1+ second laptime drop in a 135whp pseudo-EP car going from a Torsen), but the Torsen won't noticeably hold you back.

Get into the 250tq range, and it'll be pretty apparent on tighter corners that you've got wheelspin issues.

I think Emilio has a 3.63 OS Giken for sale.