11 replies to this topic

[EVOMAZ]

I'm currently in the process to change the rear end of my 1993 Spec Miata. After some research I see that the 1999 Rear Torsen Dif type 2, is the most common being used. I also know that the 2003+ Tochigi Fuji Super LSD Torque sensing cone clutch type is also a good option. Which one would you go with?

[Keith Novak]

The Tochigi isn't legal for SM. I've also heard it's not as good on the track. The torsen is a good strong diff but heavier than the Mazda comp. I haven't heard much about the new legal diff to replace the impossible to find Mazda comp.

[Wes Saunders]

I have never heard that the TFS LSD isn't legal? Can others chime in?

[Glenn]

EDIT

[Keith Novak]

I have never heard that the TFS LSD isn't legal? Can others chime in?

Transmission/Final Drive
a. Transmission and final drive ratios must remain stock for the
year of car. Any 1990-2005 Miata transmission and required
items for conversion may be used. 1999-up cars shall only use
the 5 speed transmission and the 4.3 differential ratio. All cars
may use the stock unmodified OEM open differential or one of
the approved alternates listed below.
b. 1990 to 1993 Miatas may use the stock, unmodified viscous
limited slip differential or the MAZDASPEED Motorsports
Development limited slip differential, part number #QN10-
64-A00 (previously TOY1-27-200 & 0000-02- 5501). Alternate
MAZDASPEED #0000-02-5500 limited slip differential is
permitted.
c. 1994 and newer cars may use the stock limited slip (Torsen)
differentials from 94-05 models. Stock gear ratios must be
retained.

[Jim Drago]

We specifically allowed that diff as well, from the looks of what is quoted above, if current, it never got put in? Someone on the SMAC can chime in, but I think we did this 18 months ago or so. The torsen lock up is better, but the 2003+ Tochigi Fuji is a about 1.5 lbs lighter. My personal experience is that you get more wheel spin with the 2003+ Tochigi Fuji and no more acceleration from the weight advantage because of the additional wheel spin. The 2003+ Tochigi Fuji is/was a less expensive option for Mazda, the 2003 up 6 spd cars still come with Torsens

Jim

[Jim Boemler]

Keith's quote above doesn't even allow the Torsen for 90-93 cars, so I presume it's not the current wording.

[Keith Novak]

I think I left the last paragraph out.

[Caveman-kwebb99]

probably to busy watching my nelson ledges vid.

[MarkG]

hay buddy get that car ready for daytona need drafting partner

[Keith Novak]

Ahh...I see it went into the May update.

c. 1994 and newer cars may use the stock limited slip (Torsen
or Tochigi Fuji) differentials from 94-05 models. 4.3 gear ratio
must be retained.

Now legal. My bad. We now continue with your usual programming

[EVOMAZ]

Thank you all for the comments and advise! I have decided to run the 99 rear end Type 2....