Track rental Carnage...
 

So as some of you know My Bar rented Virginia Motorsports Park last Friday for a 1/4 mile rental. I was great weather (34* and windy, but no rain). I made 20+ passes in the Miata with the best of 13.8 @100 Nothing special. Than I let a friend take it down the track and here is the video:

http://img.photobucket.com/albums/v8...55/th_todd.jpg

Here the result:

http://img.photobucket.com/albums/v8.../th_broken.jpg

So what you think broke? Its a Torsen out of a 1995. There is a hole about and inch in the top passenger side of the rear. It still moves (not locked up). Think the Torsen is ok?

I'll get it out soon, cold outside.

I SERIOUSLY doubt its "ok"

Torsen gears. Welcome to the club! The internal gears crack then split, and every failure that I have seen has been immidiately after wheel hop.

Plan on the entire unit being junk, there was nothing salvagable from mine aside from the axle stubs, which seems consistant with other Torsen failures.

I'd say that gay thing on his helmut was the culprit.. :giggle::pitlab:

I guess he won't be letting that happen again....

Was the front part of the housing salvageable?

the little gears visible through the speed hole look like the gears inside the torsen. so no, i'd not say that the torsen is ok.

makes me sad to sell my car with its clutch lsd. :(

whoops, hate when my differential gears rip to shreads.

If you're lucky the actual gear carrier itself is OK. My R&P jumped out and cracked a cap so I had to throw the entire thing away. Plan on buying a housing (FC Rx7 housings are cheap and easy to find and they bolt right up with new bushings), a Torsen or an Rx7 LSD, and a ring&pinion.

Sucks. Don't wheelhop your car.

Front as it sits on the car? It was pretty banged up, but the housing itself had a fist sized hole in it.

In the immortal words of James May, "Oh cock..."

open rear + rx7 clutch lsd = $300 ftw

I see this option a lot. Is there a write up on it somewhere? Searching is not the answer.

Found a parts list:
You will need the differential from a 1.8L Miata, (the '99 & up seem better with the one piece axles), the LSD from a late 80's RX-7, the end circle clips from the RX-7 that hold the axles in the differential, a dial indicator to set the back lash, a 7-8" caliper to set the preload, and the ring gear and pinion from the 1.8L Miata's differential.
You may want to refresh the internal clutches in the RX-7 LSD as well. New axel seals are a good thing as well.
If you need new parts
for the LSD these numbers may still be good;
RX-7 Differential Part Numbers
Snap rings M005-27-421
Friction Plates M020-27-258
Thick washer M020-27-257
Thin washer M020-27-256
Case seals MA02-27-238A
Bearings 0221-27-350
The conversion is within the capabilities of a backyard mechanic and should take an afternoon to perform.
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Oh here a write up:

84-91 RX7 Non-Turbo Clutch Type LSDs can also fit into the 1.8 gear ring if you're looking for a good LSD as well. Clutch-types have proven superior in Drag and Road course situations as the lock under driveshaft torque, whereas a Torsen should prove better in an autox situation as it locks only when one wheel loses torque...so in the middle of corners.

The 84-85 GSL is a 3.909.

The 84-85 GSL-SE is 4.08.

You can do this conversion by two ways:

1. 1.8 open converted to RX7 LSD:

Parts:
94-05 1.8 Miata open assembly
84-91 NON-TURBO Rx7 clutch-type lsd (89-91 is a viscous, don't bother)
94-95 Miata stub shafts or 86-88 RX7 stub shafts and 94-95 Miata half-shafts
or 96-05 Miata axles (no stubs needed)
94-05 Miata driveshaft
Miata Ring and Pinion

Procedure:
Open the 1.8 miata & pull the open diff. Bolt the miata ring gear to the RX7 LSD. Drop it in, set the backlash and reassemble the housing. Swap/install as normal.

2. 86-88 RX7 assembly conversion:

Parts:
86-88 RX7 NON-TURBO differential assembly
94-95 Miata stub shafts or RX7 stub shafts and 94-95 Miata half-shafts
or 96-05 Miata axles (no stubs needed)
94-05 Miata driveshaft
Miata Ring and Pinion
Miata Pinion housing (pumpkin) (find at RX7 performance shops)
Miata Diff. Bushings

Procedure:
Open the RX7 assembly. Bolt the miata ring gear to the RX7 LSD. Swap the LSD to the miata pinion housing. Set the backlash and assemble the miata pinion housing to the RX7 carrier. Drill out the RX7 diff bushings and push in miata specific bushings. Install as normal.

*note: The 85-85 LSD will fit, however, the housing is not compatible....unless you want to convert to a solid rear axle
**note: The 89-91 Non-Turbo LSD will also fit, but shy away from these are they are Viscous LSD units and aren't worth the trouble.
***note: Replace the (2) seals on the Diff before reinstallation (MA02-27-238A $5.95)
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gay as fuck.

For some reason I could never get the right diff seals. I'll have to make note of that part number.

Got me what I think is a rear from a 95 1.8L Here is a pic. The Torsen I had was covered in cooling fins right around the vent on the case, this one is smooth? What rear is it?

smooth....hmmm, I thought smooth cases went out with the 1.6L open.

My 1.6L has a smooth housing. Miata.net has photo's in the garage section.

You handled that well.

nice little bit of carnage.