Torsen vs. Maruha
 

-Track oriented street car, minimal street driving in the summer (1-2days/week tops + to/from events).
-RS3-V2/NT01/RE-71R grip levels.
-End goal is 170ish whp.
-Street manners not crucial.
-6 speed but I'm not picky about gearing.


1. Torsen (3.9/4.1/4.3)
-$650-$900 + shipping to Canada through the various forums. More $ through a reputable vendor. i.e Treasurecoastmiata
-40,000-150,000+ miles.


2. Maruha Clutch Type 2-way LSD - http://chikaramotor.com/catalog/prod...ype-lsd-2-way/
-$800

OSGiken

Not with my current budget.

Torsen + seat time

Prices are pretty much the same for both after shipping is factored in, less if I make the drive to pick up the Maruha.

That's a built diff or are you setting it up yourself? If you're getting it built, how much extra do you think that's going to cost? It cost me $400 to get a diff setup next day.

What are you asking, do you just want validation for going and getting a Maruha?

Just flip a coin. If you're worried about wheel hop and the torsen acting like an open diff, then just get the clutch. You're not going to have enough power to break the torsen so just start driving already.

By my last post, I meant that I wouldn't be able to shell any money towards seat time with a Torsen than I would with a Maruha.


If I find a Torsen in a carrier, I may give it a go. Otherwise a shop will be setting up either the new Marhuha LSD or used Torsen.

Just trying to gauge what seems like a better option given the fact that the price is pretty much the same for either LSD.

OH those prices are just the torsen diff and not already in the housing?

I got my torsen shipped from across the country for $700 with axles, driveshaft and ready to bolt on and go.

I'm sure the diff itself (just the differential) can be had for a couple hundred right?

Depends on the seller, there are quite a few in that price range with the housing but there's also 2 recent posts in the marketplace section for about $700shipped with no housing, axles or driveshaft. Shipping to Canada isn't cheap and driving down to the border to pick it up will likely cost just as much in the end.

This vendor isn't local to me (but is reputable) so I would have to drive 9-10 hrs but the cost to set it up and install seems very fair and I won't be able to find that locally.

Looks like you already had your answer, you where just seeking approval from everyone else

Kind of, to me it seems less risky than buying a Torsen with unknown mileage/condition, especially if the price is similar in the end.

But that's why I posted this poll. Maybe I need to rethink my analogy.

You could always do an RX-7 clutch type diff if money is that tight. I have like 5 or 6 hours and $275 in mine. You will have to shim it if you want more dynamic lock but they are pretty much indestructible and you can buy new steels and clutches for them oversize from mazdatrix ($$$).

Can't take your poll as I have never used either of the options you have listed.

There's the mfactory. Pretty much untested in the miata fitment. But they're great in everything else, their clutch type design is on par or better than OSG. Tuning is unknown but they're going to be substantially easier to deal with than Jonathan "I'm going to argue the wrong side of a physics argument with someone who is a Physicist" Ludgod at OSG to get your tuning changed.

Gotta love it when people ask something and then do the complete opposite of the advice/poll response given. :facepalm:

I guess I just can't justify taking the risk of spending $800 USD on a high mileage Torsen in unknown condition when I can get a brand new, albeit 2 way clutch type LSD for the same $.

Based on the experiences of a few people I've spoken with, I am likely gonna go with the _ _ _ _ _ _. :inout:

I didn't even know the Maruha existed before this thread.

Another one I just learned about recently (via non-miata people speaking highly of it) is the Kaaz Super-Q. It's supposedly very comparable to a Giken. Again, I haven't heard of anyone using it in a miata, but it's in the price range you're talking about. I'd probably buy it before the Maruha.

I think this is the right part number but you should confirm before buying.
KAAZ 1.5 Way LSD Limited Slip Differential RX-7 85-91

I would not do any 2-way clutch LSD over a Torsen. I would specifically avoid the Rx7 LSD.

Interesting, why is that?

Out of interest, why avoid it? I have an RX7 diff that I got kind of by accident ... it's already fitted to an MX5 casing so would be easy to fit, but just as easy to pick up a Torsen or something else and sell on the RX7 diff. I can't find anything on the pros and cons of it, I was hoping it would be kind of similar to the Cusco diff I had before.

Russell.

2 way is too aggressive with decel lockup. 1.5way is what you'd want.

Dont forget that $800 lsd needs $100 worth of measuring tools to install and basic reading ability and tool use or paying a shop $400 to install. Where that $800 better be in a rust free housing and low miles to be worth $800. If its just a loose used torsen I wouldnt pay more than $300 for one.

I owned one and hated it. Feel free to search my post history for more details. I've discussed it at length in the past.

Did you shim yours?

This x100000

I paid $300 for the last torsen I bought. Got my 3.9 for free out of my auction car. Don't pay to get a torsen set up, unless its a set of 3.6 gears.

I get what you're saying. If I found one for anywhere near $300 the choice would be clear. There's 2 Torsen's in the marketplace for around $700 plus shipping without the carrier. There's another full swap for 695 plus shipping but once I factor in shipping to Canada, its easily over $850-900. Perhaps if there was something local then it would be a no brainer.

Pretty positive both of these cars have the Maruha LSD. Maybe it's hard to tell from watching a video, but watching or video the 2 way looks pretty smooth to me, it seems to be working well and not holding back the car/driver in any way?

I actively race a 250 whp mx5 on NT01 225's and 15x9 wheel and have never, ever had any issue with using a torsen on a road course. I use a 3.9 and a 4.1.

There has only been one location where I spin up a wheel and that was at the Rod Millen Leadfoot Hillclimb, a hard climbing/banked 100degree tight, right hand corner.

Even then I am sceptical a better diff would actually improve the situation, other than a locked diff maybe....

The torsens work so well I wouldn't bother with anything else....I dont know about pricing up there but your listed price seems very high....

I am not questioning the torsen's performance at all. I just can't see myself paying the same as the brand new 2 way lsd for a torsen with high mileage and and in unknown condition.

Maybe it's just the last 3 Torsen posts in the marketplace section and I'll keep looking but:
-Full Torsen swap - $695 + shipping
-Torsen WITHOUT carrier - $750 + shipping
-Another Torsen WITHOUT carrier - 750 + shipping

One of the used Miata vendors has the Torsen LSDs ranging from $800-1200 plus shipping and its unlikely that any of these have reasonably low mileage on them.

Edit: Decided to check on another forum, last 2 LSDs for sale:
-Torsen LSD w/ 20k miles + axles - $1000 obo + shipping
- 3.6 Torsen built with new gears/seals - $1250 + shipping

If I do find a good deal on a Torsen before I purchase the Maruha LSD, then that's definitely an option I would consider.

Longcat post incoming...

The RX7 diff is the most basic clutch type diff. The force squeezing the clutches together is a constant that is set by a simple spring. The amount of lock is the same for accel, decel, and off-throttle. You can increase the lock force with a stiffer spring (or a shim) or you can decrease lock force with a softer spring (or by machining the case.) As the clutch discs wear and become thinner, the spring is compressed less and the lock force slowly decreases.

The Giken and the Kaaz are both 1.5-way Salisbury-type clutch diffs. With a Salisbury, ramps between the left and right side of the diff control clutch slip based on the amount of torque being transmitted through the diff. With a 1.5 way, you have different ramp angles for accel and decel, so you get different amounts of lock for each. On accel, you transition from a basically open diff at very light throttle, up to a max lock amount at full throttle. On decel, you get a small amount of lock when you lift the throttle and a larger amount of lock under braking, but the max decel lock is less than the max accel lock. On a 2-way Salisbury, the max lock amount is the same for accel and decel.

Some people call diffs like the RX7 diff "2-way" because they're the same during accel and decel, but they shouldn't be confused with a 2-way Salisbury. On the 2-way RX7 diff, the force squeezing the clutches together is ALWAYS the same. On the 2-way Salisbury, the ramp angles are the same, but the force squeezing the clutches together is completely based on the driver's throttle and brake inputs.

A 2-way Salisbury can be just as fast as a 1.5-way Salisbury... it just depends on driver skill and preference. You can adjust your driving to suit the strengths and weaknesses of either. The biggest downside I can see to a 2-way Salisbury is that, for an inexperienced driver, or even for an experienced driver who has to react to an oh-shit situation, lifting the throttle mid-corner will cause more diff lock than with a 1.5-way, possibly turning a small situation into a big one. 1.5-way diffs are so popular for track use because less decel lock is usually easier to drive for most people.

Maruha barely has any info on their website, but based on the small grainy picture, it looks like the Maruha is a 2-way Salisbury to me.

I came across this earlier.

http://www.maruhamotors.co.jp/miata/...dlecture2.html

Maruha LSD Miata MX-5

I started to edit my post but decided to leave it as original. I was wrong about the RX7 diff. It's a 2-way Salisbury. Pictures of the internals here:

My 85 RX7 non-turbo LSD rebuild and question thread! - RX7Club.com

Kaaz sells there diffs under many different names (Tomei is one for example). Typically they are just "customize" to each brands liking by flipping the plates to get different characteristics. You maybe able to call Kaaz USA and they can give you a little help into the what the Mahura setup is like compared to the base setup.

Sometimes you can find good deals on Torsens on Ebay.

Did people stop doing the OBX with improved fasteners? I don't remember hearing if anyone was satisfied with that setup.

Pretty sure the OBX went up in price a decent amount.

The OBX diff is available for $360 shipped on eBay (link) or $378 with Amazon Prime ( ).

I have no personal experience with the unit, but one would think that it would be worth a try, especially if you can swap it into the housing yourself (i.e. swap the ring gear over, measure/adjust preload on carrier bearings).

The first post in this thread with real information. Thank you - great post.

Earlysport

People do it all the time for other cars, works great. No one in their right mind does it for our cars because you can get a real torsen for cheaper.

This guy still was using an open diff :



Not bad... and he bought a torsen pumpkin for this year...