Modena R180 Rear Limited Slip Differential

Modena Engineering has a hard fought and well earned reputation for producing gears, transmissions, and differentials that will outlast and outperform anything else in a racing environment.  Their parts have helped put countless Porsche's on the podium at all levels of motorsport.

And it may not be quite as well known, but they also have a very well established history for making that same level of competition parts available for Subaru's.

This Modena rear differential is the latest version of the one that was used in Roger Clark Motorsports Gobstopper I and Gobstopper II in fact.  Modena Engineering was also the first company to develop a sequential transmission for the STI 6-Speed transmission, and versions of that transmission have been used in the highest levels of competition for more than a decade.  

What sets the Modena rear differential appart from the rest?

If you have watched our video about how limited slip differentials work, you know that the key factors for how a differential will be have are the clutch disks, the pre-load on those disks, and the ramp angle that applies pressure to them.  The Modena differential is unique in part because of how few friction disks it uses.  There are far fewer than in many other differentials, and the reason for this is the propriatary friction material that Modena applies to the surface of the clutch disks.

This creates significantly more friction with fewer disks, and this has some distinct advantages.  The main one being that the Modena differential can make much more effective use of the ramp angles to achieve lock-up, as opposed to pre-load.  This gives the Modena differential a unique feel and behavior that is unlike most anything else on the market.

The progressive nature of the Modena differential lets the diff be open when you want it to be open, and then lock up when you would want that lock.  It sits somewhere between a torque biasing (gear type) differential and a traditional LSD in that sense.  And ultimately what this gives you is a locking differential that feels very smooth.  And that shoothness translates into a more predictable behavior than anything else.

There is a reason so many cars have won races and championships with a Modena differential.

This differential is designed for competition use, and is built and designed with the same exact standards as all of their other differentials.  But this differential can be used on the street as well.

In competition use, it is recommended to inspect and re-build this differential every 3 - 5 seasons.  Under street use, because of the lower overall traction of street tires, the Modena differential would rarely need any re-build.

This is a ramp-and-plate design (multi-plate, multi-ramp) limited slip differential.