17 replies to this topic

[SaulSpeedwell]

If you think your Torsen "wore out", you weren't imagining it! 

 

 

 

[ChrisA]

Very informative. Thank you! What fluid are you feeling may be best for this unit? I had been using Redline 75-90 and switched to Redline Shockproof at their recommendation for a few seasons. I usually only change the fluid at the beginning of the season. However, after I and the car sat out a season and I went to drain the fluid, I had found it congealed. Apparently, something in the Shockproof fluid is hydroscopic and needs to be replaced at least yearly. I switched back to the standard fluid to clean out the diff a bite. The Shockproof does have wonderful cling properties.

[Ron Alan]

MB,

 

Ok...just a matter off replacing the plates and washers? If so, a source for those parts?

 

This is a T2 correct? 4 screws on the ring gear end and it all dumps out? At one point we experimented with adding a "coke can washer" and it seemed to help...is this on the correct path/thinking?

 

Can the T1 be taken apart easily?

[SaulSpeedwell]

Very informative. Thank you! What fluid are you feeling may be best for this unit? I had been using Redline 75-90 and switched to Redline Shockproof at their recommendation for a few seasons. I usually only change the fluid at the beginning of the season. However, after I and the car sat out a season and I went to drain the fluid, I had found it congealed. Apparently, something in the Shockproof fluid is hydroscopic and needs to be replaced at least yearly. I switched back to the standard fluid to clean out the diff a bite. The Shockproof does have wonderful cling properties.

 

I think Redline makes some very good products, but I wouldn't recommend either of those specific fluids for THIS diff.  Like any powertrain device with "clutches", we are looking for the right amount of friction, not the minimum amount of friction.  If you want to talk about fluids in more detail, email me, so as to prevent a flame war

[Johnny D]

Just a little flame war, please

J~

[SaulSpeedwell]

MB,

 

Ok...just a matter off replacing the plates and washers? If so, a source for those parts?

 

This is a T2 correct? 4 screws on the ring gear end and it all dumps out? At one point we experimented with adding a "coke can washer" and it seemed to help...is this on the correct path/thinking?

 

Can the T1 be taken apart easily?

 

I wish it was that easy!  I don't know of ANY source for parts for the internals of this Torsen.  I've run some limited batches of what is needed to rebuild and tune the Type 2 for more "lockup", but ~10% of the units I've seen thus far aren't worth rebuilding or blueprinting ....     

 

The Coke can shim IS in the helpful direction and a good stopgap or "Run her till she blows!" option for DIY-ers with time and patience, but it is a bit of a brute force "hack", and I think you'll find that the shim will have shredded and/or melted after a short while .

 

I haven't endeavored to figure out the Type 1 yet.  It took me years to get around to the Type 2! 

[SaulSpeedwell]

Just a little flame war, please

J~

 

Texas sucks? 

[Tom Hampton]

Texas sucks?

Hey, now! Pick on cali! They are the lunatics. .

[FTodaro]

I tore into a torsen to rebuild it, when i called torsen directly i was told that they do not see rebuild or replacement parts. So if you plan on rebuilding them, you will have to fabricate those parts.

[MPR22]

Hey, now! Pick on cali! They are the lunatics. .

Tom, 

 

Mark is a Master Baiter.  

 

He is just jealous Texas has a flag that is ranked higher than the Ohio flag.  

 

http://www.nava.org/...ial-survey-2001

[Jamz14]

Yes the lunatics are in California. But all the best people I know are a bit crazy. Viva California.

[SaulSpeedwell]

Tom, 

 

Mark is a Master Baiter.  

 

He is just jealous Texas has a flag that is ranked higher than the Ohio flag.  

 

http://www.nava.org/...ial-survey-2001

 

Well, that's because everyone from Chile and Cuba accidentally voted for it? 

(Disclaimer:  This is a flag similarity joke, not intended as a racist comment!)

[SaulSpeedwell]

A little trouble keeping up with all the emails. 

 

Answers to the FAQs ....

 

1.  Super-slick fluids with LSD additive are not helping us with this diff.  When wheelspin is the issue with this diff, we want more shear friction, not less.  I'm working on fluids, but if you want to "do no harm", use any GL-5 fluid *WITH NO* LSD additive. 

2.  But .... like the Comp LSD, the "clutches" need WASHED to get their effectiveness back once they are soaked with LSD additive.  We have tried "on-car" methods of cleaning and flushing, but thus far have not had results that were good enough to approve and publish.

3.  If you just jam shims in the outboard end of the diff, you are making a weird diff that is asymmetrically biased to the left side.  Unless you are racing left-hand ovals, this is not the best option.

4.  It is hard to get the diff back together without fixturing.  I love and will always help DIY-ers, but this isn't a high bang-for-buck DIY activity.  Do not expect to take a Torsen apart and get it back together on your first try.

5.  Measuring the Torque Bias Ratio is not easy and requires a dynamic fixture - so no point in trying to do anything with a torque wrench.  Unfortunately, static torque wrench readings are worthless because once this Torsen "feels" drive torque, the side gears "thrust away" from the center and whatever "breakaway torque" was measured statically ends up disappearing. 

6.  "Return to factory specs" has cured all complaints thus far - so this is not one of those "Oh No, we're on a slippery slope of becoming E Production!" issues.

7.  I'll happily sell any of the rebuild parts I've had made when I can, but I've only got enough to handle the current backlog of rebuilds, at present.

8.  Light reading:  http://www.zhome.com...rsen/Torsen.htm

[SaulSpeedwell]

Not all Type 2 Miata Torsens are created equal! 

 

[FTodaro]

Mark is one of those mine? Are they both Torsen II or what is the distinction between the two?

[Ron Alan]

Mark...early Torsen 2's, which I think started in 96 don't have the tell tail washer look when you look threw the axle hole. They look like a Torsen 1 which has nothing...until you remove the carrier/housing to reveal something that isn't a Torsen 1! Pretty sure the 99+ start with the first T2 with the center piece of metal. I'm sure you know this but good info for others.

[SaulSpeedwell]

Mark is one of those mine? Are they both Torsen II or what is the distinction between the two?

 

No, but yours looks like the one on the right.  Your Torsen part number is 4030-8Z02436 (more on this in a minute). 

 

To Ron's point, we see a lot of stuff these days that aren't what the car originally would have come with, just because so many donors were retrofitted with Torsens and original Torsens "wore out".  Not an issue rules-wise, as long as it is one of the original Miata LSDs as fitted by Mazda.

 

Torsen "part number" schemes on the edge of the diff itself change over the years and by OEM.  The last five digits are always SERIAL number, so ignore these when scrounging parts or trying to look something up by part number. The first 4 digits are "type" - whether Type 1, early Type 2, or late Type 2.   

 

More to Ron's point, for SM Torsen users, just try to get a "4030-.........." Torsen, as these can be blueprinted like the one on the right in the video.  His spotter's guide tip is a good one!  Look for the washer!  The unit on the left is a "4020-.....", probably from a 96-97 car, although I'm told it came from Japan. 

 

 

4020:  Early Type 2, as shown above on the left.

4030:  Later Type 2 (preferred), as shown above on the right,

[Tom Sager]

No, but yours looks like the one on the right.  Your Torsen part number is 4030-8Z02436 (more on this in a minute). 

 

To Ron's point, we see a lot of stuff these days that aren't what the car originally would have come with, just because so many donors were retrofitted with Torsens and original Torsens "wore out".  Not an issue rules-wise, as long as it is one of the original Miata LSDs as fitted by Mazda.

 

Torsen "part number" schemes on the edge of the diff itself change over the years and by OEM.  The last five digits are always SERIAL number, so ignore these when scrounging parts or trying to look something up by part number. The first 4 digits are "type" - whether Type 1, early Type 2, or late Type 2.   

 

More to Ron's point, for SM Torsen users, just try to get a "4030-.........." Torsen, as these can be blueprinted like the one on the right in the video.  His spotter's guide tip is a good one!  Look for the washer!  The unit on the left is a "4020-.....", probably from a 96-97 car, although I'm told it came from Japan. 

 

 

4020:  Early Type 2, as shown above on the left.

4030:  Later Type 2 (preferred), as shown above on the right,

Saul, I think we can officially call you a "gear head" now.