How do you set up a posi transaxle

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jr_vw2
Posts: 128
Joined: Tue Sep 06, 2005 8:00 pm

How do you set up a posi transaxle

Post by jr_vw2 »

How do you get a pois traction out of a type one IRS transaxle with out buying a new unit. Do you just put in a superdiff and weld the gears? ANy help would be great. Thanks.
CairoManx
Posts: 858
Joined: Sat Mar 26, 2011 5:00 am

Post by CairoManx »

A "super-diff" is not the same as "Posi-traction". On a VW a super-diff is just an extra pair of spider gears that engage the ring gear. The super-diff carrier looks like a posi, but its not. Stock VWs have two spider gears, super-diffs add two more gears and effectively spread out the force on the ring over more teeth at once, so you have less of a chance of breaking a ring gear tooth. Posi is the same as a limited slip differential. A limited slip differential(LSD) is basically a pack of clutches that mount within the ring gear carrier that keep both rear wheels turning even if one loses traction. The LSD will allow one axle to turn a limited amount more than the opposite axle so the car can turn corners. However, if one wheel looses traction and starts to spin, the clutches will lock up and force the opposite axle to turn also. VWs have what is called an open differential(no LSD). There were LSDs made for VWs. They used to be a fairly common performance mod in the 60s. EMPI used to sell ones made by ZF I believe. They may still be available, but are probably fairly rare/expensive. There is a British company named Quaife that manufacture LSDs. They may make one that would fit. I suppose you could weld the spider gears so they wouldn't turn and it would probably work great in a dragster. However, if you needed to turn left or right at all, it would suck.
fubar
Posts: 425
Joined: Mon Apr 11, 2005 8:00 pm

Post by fubar »

Turning brakes should do the trick for about $100 and some plumbing.
newmanx59
Posts: 864
Joined: Mon Mar 14, 2005 9:00 pm

Post by newmanx59 »

One problem you run into when you weld the spyder gears is the fact that the vehicle will make an instant 90 deg turn, if and when an axle breaks. When this happens it is always at the worse possible time.
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