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-   -   Torsen vs. Maruha (https://www.miataturbo.net/race-prep-75/torsen-vs-maruha-88193/)

90civichhb 03-17-2016 07:30 PM

Did you shim yours?

aidandj 03-17-2016 07:32 PM


Originally Posted by Leafy (Post 1316626)
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.

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.

k1l4m 03-17-2016 08:44 PM

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?

mx5-kiwi 03-17-2016 09:10 PM

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....

k1l4m 03-17-2016 09:19 PM

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.

jpreston 03-17-2016 09:56 PM

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.

k1l4m 03-17-2016 10:12 PM


Originally Posted by jpreston (Post 1316655)
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

jpreston 03-18-2016 12:23 AM

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

Midtenn 03-18-2016 01:00 PM

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.

wannafbody 03-18-2016 09:08 PM

Sometimes you can find good deals on Torsens on Ebay.

kaisersoze 03-18-2016 10:01 PM

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

aidandj 03-19-2016 12:13 AM

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

noname4me 03-19-2016 10:54 AM


Originally Posted by aidandj (Post 1316916)
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).

Earlysport 03-21-2016 04:19 PM


Originally Posted by jpreston (Post 1316655)
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.

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

Earlysport

Leafy 03-21-2016 07:35 PM


Originally Posted by kaisersoze (Post 1316909)
Did people stop doing the OBX with improved fasteners? I don't remember hearing if anyone was satisfied with that setup.

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.

joyrider 03-25-2016 11:38 AM

This guy still was using an open diff :



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


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