924Board.org

[oharris]

I know the G31 is actually an Audi trans. Are there any Audi's that came with a compatible Limited slip diff that could be swapped in?
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'80 931

[Mike9311]

[morghen]

G31 is not the same like 016(Audi box)
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Supercharger and EFI kits
https://www.the924.com

[Power Tryp]

This is something I've done quite a bit of research into. Your 931 being a 1980 should have the G31 transaxle but a little confirmation never hurt anybody. http://garage.ideola.com/downloads/G31-Transaxles-PeteTinucci.pdf

There's good info in there.

On to the Limited Slip portion. The G31 transaxle uses some components of the somewhat maligned Porsche 915 transaxle used in 911's for years. The irony being that the G31 and 915 suffer some of the same issues in drive-ability. However! There is good news to be had from that. One of the shared components between the two transaxles is the differential. What does this mean to you? It means the world is your oyster when it comes to LSD.

Clutch type:
http://www.kaazusa.com/lsd_porsche.html

http://www.osgiken.net/products.php?Category2=porsche&SubCat2=915%2F930+type+mt&submit.x=23&submit.y=14&product=lsd

http://www.ppi-ats.com/LSD/LSD_%20appli_Oct_%202010_Porsche1.pdf

Those are the racing clutch type differentials from just a few producers, there are more out there.

Helical Gear type:

https://shop.quaife.co.uk/porsche-911-43t-quaife-atb-helical-lsd-differential

http://www.ebay.com/itm/OBX-LSD-LIMITED-SLIP-DIFFERENTIAL-PORSCHE-78-88-930-924-/161843542029


I did research into this because the well known Quaife diff fits the G31 application and is the exact same differential listed for the 915 transaxle. the OBX diff on Ebay there does the same thing from all vendors (beware quality issues).

So it stands to reason that any 915 specified differential with the 43 spline side gears should fit. I have not had the money to test this theory out yet but it is high on my list when I start building my "track" car.

Hope this helps, good luck and happy hunting.
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Melanie - 1980 931
NoName - 1980 931 (seeking rebuild)

Green tartan interior, you don't see that on a Civic.

[oharris]

Mine is an S1. So I guess it's its own beast and I'd have to find another Porsche? No wonder Ideola is always looking for those.
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'80 931

[ideola]

G31 was not built by Audi (pretty sure it was manufactured for Porsche by Getrag, hence the "G"), nearly the same as the 915 boxes, but with some 931 peculiarities that are well-documented in the above-linked tech guide from Pete Tinucci.

915 had a coarse- and fine-splined diff, I don't remember the different spline counts offhand, should be in that article. I think the G31 uses the fine spline setup (please confirm), so if you look for a 915 swap-in solution, you need to make sure you get the right spline setup.

I have managed to locate five LSD units, but they are all spoken for (Club Sport, 941, DProd tribute, 937, and GTR tribute). Apparently, they are more common here in the states, even though the G31 was only in US cars in 1980, whereas it was in the ALL of the ROW cars.

The best chance to find a G31+LSD is to search for 1980 cars with five-lug + Gullideckel rims. Every LSD I found was on a car so-equipped, but not every car with 5-lug Gullies has LSD. Buying a 915 LSD is going to cost you 911 dollars (shhhhh, don't tell the 915 guys that the G31 LSD fits in their cars!).

Good luck!
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erstwhile owner of just about every 924 variant ever made

[Rasta Monsta]

Have you spent much time driving the car yet? Fwiw, my hot rodded 931 has zero wheelspin/traction issues, including on the track. Not sure why...my 924s race car really needs LSD.
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Toofah King Bad

• WeiBe (1987 924S 2.5t) - 931 S3

[v8carreragts]

The G31 uses the late type 915/930 fine spline which means you could swap in 930 drive flanges and use the big CV's. You can also buy stub shafts for 930 size CV's.
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84 944--924 Carrera GTS clone w/520HP Chevy 302 V8--RUNNING!
2015 AUDI Q7
2013 Dodge Charger R/T AWD HEMI
2013 Chevy Cruze

[Mike9311]

...and add this to my LSD link file
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1980 931 since 1989
1981 Ideola 931 Club Sport
1982 931 Entwicklungsfahrzeug
1979 924 NA ohne 650 mit 471
1982 931 Red Resurrection - 951 IC
1982 931 parts car / resurrection?
1980 924 NA (R&D lightweight)
1982 931 wana-be GTR race car

[ideola]

[Cedric]

[Rasta Monsta]