3.07 lsd? what fits our cars?

[Reach]

Since I'm in the vast minority with the SMG crew, my diff options are rather limited. I think the best thing I can do for my car at this point might be a stock ratio, but limited-slip diff. 3.07 for us 03-05 6-speed'ers.

This is an expensive project to have made from a stock diff, so I'm curious if anyone knows about any shortcuts, like other models diffs that fit our housings, or work as a whole housing swap.

Just a thought / pet project. But, one day I hope to do this.

 

[Curtis]

As far as I'm aware the only diffs that come with an lsd as standard nowadays are the M models and the M diff isn't a direct replacement for the standard unit, you have to fit the whole axle. You can get aftermarket lsd's from Kaaz, Quaife, etc which can be fitted into your standard casing. The prices in the States seem to be around $800-1000 for the lsd and then you have to allow for labour time to fit it. If you fancy a bit more acceleration at the same time it might be worth sourcing a cheap 3.23 diff. This also allows you to swap back to the original if you ever sell the car and you can keep your lsd. It just so happens that I have a spare low mileage 3.23 diff in the garage somewhere if your interested!! :wink: Come to think of it I also have a spare low mileage M3 3.62 lsd if any of you Z4M drivers fancy a spare!!

 

[GP20]

Any other differential ratio wouldn't work with the Z4's SMG/SSG other than the stock ratio.

 

[Curtis]

That's a shame, I thought you just reprogrammed the software.

 

[epbrown]

That's a shame, I thought you just reprogrammed the software.

Dinan was supposed to be working on a software fix, but I think they dropped it due to lack of interest - the market isn't big enough to support the effort.

 

[Reach]

I'm honestly not sure Dinan ever cracked the code on the SMG shift patterns themselves. The SMG II in the E46 M3 could adapt to new ratios somehow - with or without the Dinan software. But, apparently if you put a higher ration diff in an SMG (I) Z4 or E46 all you get is bad, clunky shifts.

Back to wondering, has anyone ever had a diff converted to LSD? Who did it and how much did it cost?

 

[Curtis]

I just put a complete M3 back axle in mine but I'm sure FemmeT had an aftermarket LSD fitted in her car. Turner Motorsport supply LSD's either complete with casing etc or just the LSD parts but I couldn't tell you who would do the work for you over there or at what cost. To give you an idea though I had a 3.23 axle built for a customer over here using a Kaaz LSD. Birds BMW did the work for me and supplied the LSD, I think the LSD was around £900, the labour time was 3 hours ( just to fit the LSD in the casing ) and I paid £300 for the donour 3.23 diff. You will have to add a few more hours labour time for them to remove and refit your diff to the car.