LSD on the IX

[droppa]

fellas i seein the evo IX carriestwo lsd, a helical lsd in front and a clutch type lsd in the back. wts the difference between these?

[Sanctifier]

This is on the US spec Evo IXs; or GT and RS models in UK and JDM AFAIK.
UK/JDM MR and GSR models come with Super AYC differential;
while (new) GT and RS models have clutch-type LSDs as usual.

To get an idea of the differences between standard LSD types check - http://www.houseofthud.com/differentials.htm

Rear LSD is a conventional clutch-type LSD.
This is used by all pro rally teams until recently,
(when most went to "active diffs", front and rear in the WRC.)

Front LSD is a "Torque sensing" (TorSen) type. It has helical gears instead of clutch-discs.

TorSen Info - (sic MazdaTrix - http://www.mazdatrix.com/g8.htm)

Torque sensing differential limited slip units. They really are the absolute best design for rear traction under ALL different conditions.
It is able to transmit far more torque to the wheel that still has traction than any other type of differential.

It uses the friction of the worm gear teeth and the thrust washers for the differential limiting force. In comparison with viscous type, or friction type LSD, it has the following benefits:

1) No special differential oil or LSD additives needed
2) Improved overall traction and improved controllability under acceleration.
3) Smoother activation vs. �clutch-type� LSD, reduces clutch-type induced understeer.
4) Slightly increased oversteer / Reduced need for huge rear anti-roll bars.
5) No �typical� inside rear wheel spin on corner exits, like "open" diffs.
6) Corner exits are smooth, with a touch of oversteer (with both rear wheels spinning!).
7) Later apex usually required due to higher exit speeds and power induced oversteer.
8 ) Allegedly more fragile than �clutch-type� LSD (*questionable*).

More Info: TorSen - http://www.billzilla.org/diffs.htm AND http://www.mazdatrix.com/g8.htm

BTW this is a standard rear LSD in Evo 3's and 4wd 1800 GSR's.
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