In the process of installing my Quaife LSD unit in my medium size case 2.79. The thickness of the LSD where the ring gear bolts to is 7.45mm thicker then removed open diff. I am assuming I need to run a ring gear / pinion set from a LSD car? Or have this ring gear turned down in a lathe. Anyone else have this issue?
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Had to look it up, wasn't in my instant memory. Thick one is for 3.15-4.45+, thin one is 2.79-3.07Last edited by ForcedFirebird; 10-31-2022, 12:04 PM.Comment
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i've swapped med case ring gears between open and ls carriers previous but have never pulled one from a 2.93. there may be a size difference with the 2.79. i've rebuilt ls units but have never installed a quaife unit.
i can confirm it's possible to swap gearsets from open to ls units from the other med case diffs.
edit : firebird's post above has the spec for the carrier. i never knew there was a 3.07.Comment
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Thanks for the knowledge guys. I am in the process of sourcing a 2.93 ring and pinion off of a factory LSD unit.Comment
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LSD and open ring/pinions are identical. It's the center carrier that dictates open and LSD.Originally posted by E30TouringS52 View Post
In your pic, the carrier on the right will accept 3.07 and less gear sets, the one on the left is for 3.15 and more. If that gear is from carrier on the left,, then you have it on the wrong carrier - you need to find a 3.15+ ring/pinion to use that Quaife. Honestly I use the 3.15 in a lot of ZF swapped cars and it's a good ratio.
The ring and pinion have numbers on them to indicate what ratio you have.
Compare the size of the two pinion gears, and you'll get a visual. The 2.93 set should be 41 teeth on the ring gear and 14 teeth on the pinion. If you imagine a 4.27 has 47 teeth and 11 teeth - a pinion gear with 14 teeth is going to be 20% larger, which will need the ring gear moved outboard to compensate - therefore causing a thinner ring gear flange.Last edited by ForcedFirebird; 10-31-2022, 12:12 PM.Comment
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Edited. I had reversed my info. Larger pinions (lower numerically) have the carrier further offset, smaller pinions have it more centered.
Actually went to the back of the shop where we have some diffs opened up to verify.Last edited by ForcedFirebird; 10-31-2022, 12:13 PM.Comment
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The ring gear came off the open diff on the right. Yea, now that i'm thinking about it. I am willing to source out a 3.15 ring and pinion. I mean it's either that or source a wavetrac that can take a 2.93. The car is a fully built S52 / 62mm borg warner, 6sp 330 ZHP gear box. SRS concept has a nice table with all H markings on ring gear. I believe 3.15 is H23. Thanks again.Comment
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i was going to swap ratios in my diff and did some research, and with some help from members on here. found that i was going to swap from a 2.93 to a 3.73 but i need to get this spacer
https://racingdiffs.com/products/bmw...33487610675335
i ended up finind someone that wanted a even trade for my diffComment
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