We mostly use KAAZ 1.5 way diffs in the FWD race cars, have done for over 30 years. In that time I have serviced 1 diff due to wear and reduced function and that was after 3 x Bathurst 12 Hour races and 4 x 6 Hour races. That's equivalent to hell of a lot of road kilometres. My experience is that the need to service them at short intervals is an urban myth. Personally in a road car I'd throw some new plates in whenever I serviced the clutch and that's about it. We do use torson diffs in some RWD race cars and we service them every off season, they wear out the ramps as evidenced by the metal in the diff oil at every change. Torsons are horrid for race drivers that have an affinity with jumping the car off the curbs. FWIW KAAZ make a lot of plate diffs that are sold under other brand names.
In a FWD car, especially those with high torque levels, a plate style diff is much easier to live with every day, they are gentler in engagement and don't provoke torque steer like a "locking" diff does. Viscous diffs are the best for gentleness in a road car, but they allow too much unloaded wheel spin on the track. At the other end of the scale the locking style of diffs can be uncomfortably savage in their engagement / disengagement. Plate diffs are the goldilocks, just right, in the middle.
I think Sam covered the FARB debate very well (spring rate versus anti roll rate), if I was running a FWD car in a gymkhana/motorkhana event with lots of very tight short duration low G corners then I probably consider it. But with open corners, high lateral G and plenty of diagonal weight transfer a FARB is a necessity.
Cheers
Gary
Golf Mk7.5 R, Volvo S60 Polestar, Skyline R32GTST
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Originally Posted by sambb
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