Over torqued diffs? - Drifting forum

griffo20022 · 06-10-2008, 00:10

Hey guys, well i've decided on the 325 I wanna go the LSD route rather than a welder. I've just been reading about and noticed a mention of "Over torqued diffs"? What is this exactly?

I'm assuming it obviously locks better than the diff in stock form, but whats actually involved in doing this??

20vWill · 06-10-2008, 11:43

"Over torqued" is not really the correct way of describing it, but it is simply shimming the pack to put more preload on the clutches, allowing it to lock up quicker and slightly stronger and also wear the plates out quicker too haha.

Process is easy, strip the LSD, measure the plates thicknesses and add suitable shims to increase thickness to press more preload on the packs. It's important to get both sides very similar overall thicknesses. Adding shim ramps up preload quite quickly once you get to a certain point of "bite".

Known as simply "shimming", just increasing initial preload really. BMW LSD's have a very low initial preload as stock to make them smoother and more user friendly, unfortunately this makes them shit at locking rather quickly as plates wear.

Even though I actually build LSD's, I'd recommend a welder for a drift car as LSD's get expensive if you want them done properly!

griffo20022 · 06-10-2008, 21:38

arrrr right didn;t realise it was just another term for shimming.

I think I do fancy the route of an LSD still. The level i'm at I dont need no fancy super duper diff as I can't exactly do super fast entries or anything hehe, just something thats enough to have some fun with more than anything.

what sort of price is it for having a diff shimmed?

By all means PM me if you'd prefer Mr Will

06-10-2008, 00:10	#1 (permalink)
griffo20022 BMW Driver... Join Date: Sep 2006 Location: Wolverhampton Posts: 1,234	Over torqued diffs? Hey guys, well i've decided on the 325 I wanna go the LSD route rather than a welder. I've just been reading about and noticed a mention of "Over torqued diffs"? What is this exactly? I'm assuming it obviously locks better than the diff in stock form, but whats actually involved in doing this??

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06-10-2008, 11:43	#2 (permalink)
20vWill ...... Join Date: Jul 2004 Location: Doon Sooth Posts: 3,856	"Over torqued" is not really the correct way of describing it, but it is simply shimming the pack to put more preload on the clutches, allowing it to lock up quicker and slightly stronger and also wear the plates out quicker too haha. Process is easy, strip the LSD, measure the plates thicknesses and add suitable shims to increase thickness to press more preload on the packs. It's important to get both sides very similar overall thicknesses. Adding shim ramps up preload quite quickly once you get to a certain point of "bite". Known as simply "shimming", just increasing initial preload really. BMW LSD's have a very low initial preload as stock to make them smoother and more user friendly, unfortunately this makes them shit at locking rather quickly as plates wear. Even though I actually build LSD's, I'd recommend a welder for a drift car as LSD's get expensive if you want them done properly!

06-10-2008, 21:38	#3 (permalink)
griffo20022 BMW Driver... Join Date: Sep 2006 Location: Wolverhampton Posts: 1,234	arrrr right didn;t realise it was just another term for shimming. I think I do fancy the route of an LSD still. The level i'm at I dont need no fancy super duper diff as I can't exactly do super fast entries or anything hehe, just something thats enough to have some fun with more than anything. what sort of price is it for having a diff shimmed? By all means PM me if you'd prefer Mr Will