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 just could be more $

 

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.