Kompakt gears in a 210mm case?

[moroza]

Does anyone have any info on the possibility of adapting 215K gears to a 210mm case? They have some ratios the 210 didn't, and my hunch is that it's better to modify gears (ideally if it's just a matter of spacers/sleeves) than diff cases.

[pbonsalb]

Waganstyle would know.

[wanganstyle]

Does anyone have any info on the possibility of adapting 215K gears to a 210mm case? They have some ratios the 210 didn't, and my hunch is that it's better to modify gears (ideally if it's just a matter of spacers/sleeves) than diff cases.

No.

Spacers in the differential is a bad idea; Modifying gears is also very bad idea;

Use what’s avail off the shelf as is or feed a Ford 8.8 IRS rear if your fabrication skills are up to par.

The entire 215k kompact unit can interchange with a 215mm non kompact if desired in some chassis; I.e e92 335 is 215k and has a dct 2.56 avail; these gears are welded to the open diff by bmw from the factory but an aftermarket ring and pinion set is avail for about $800 from m factory.


The 215k has some rather difficult to acquire (for genuine Oem) expensive ass pinion bearings with different standards case side but realistically it works fine for a x5d or 335d amount of stress from the factory (469lb-ft stock)


Pictured is a new parts pre assembly of an e92m unit; the e92m and e60m are Rosetta Stone units as the 215k bearings are used with a brand new 210mm gearset by BMW Motorsport but the iron housing and side bearing standard + differential are classic 210mm shared with the e28m5.



If budget was no object then one could just create a lsd to drop in; I did this for 188k

Bmw Drexler sells a fantastic 215k lsd unit for the 335/340/240/440 from the parts counter. Sadly Few have taken advantage of this support.

Pictured below is a 188k prototype Wanganstyle original lsd for zf platform internals. A 215k setup could be easily produced if there was actual market consumption (at a feasible for production price — not cheap)

[moroza]

Thanks!

First I hear of a "215mm non-kompakt". I assume that's a typo, and you meant 210mm?

I love Rosetta Stone hardware, but I don't get why 210mm gears and cases would take anything other than 210mm bearings. If they take 215K bearings, that suggests to me that the bearings are dimensionally the same.

2.56 is not worth the trouble over the 2.65 currently on my shop floor, assembled and tested ok over ~3.5 years (I sold the 544iT with its original S3.15). It's the 2.28 fitted to E46 330d I'm most interested in.

[wanganstyle]

Thanks!

First I hear of a "215mm non-kompakt". I assume that's a typo, and you meant 210mm?

I love Rosetta Stone hardware, but I don't get why 210mm gears and cases would take anything other than 210mm bearings. If they take 215K bearings, that suggests to me that the bearings are dimensionally the same.

2.56 is not worth the trouble over the 2.65 currently on my shop floor, assembled and tested ok over ~3.5 years (I sold the 544iT with its original S3.15). It's the 2.28 fitted to E46 330d I'm most interested in.

Not a typo; I wish it was.

Key point= OD; not ID.


OD is decided by the hole bored in the iron case. A larger hole is easily bored with ID kept same; different bearing entirely - designed for fuel economy


210mm classic->215k kompact for non m and the weird ass 215k non kompact for only 92/90m and 60m.

I don’t know why but the theory is Bmw has taken some serious drugs over the past decade and now there are a bunch of stupid standards.

E92m/e60m uses a classic 210mm lsd and output bearings.
The gearset is also a classic 210mm

The housing does not take a 210mm bearing; it takes a 215k pinion bearing pair shared ironically with 335/e38/e39 540i

A e39 540 uses 215k kompact pinion bearing set and 215k output bearings. Not the same as 210mm output bearings; total fuck screw to owners as these parts are not sold by bmw or the bearing manufactures. Stupid af and annoying

I know this only because I build new units for local shops/customers - Also stock all the new service parts and housings naked on my because they are not easy to come by; bmw pulled the plug and doesn’t support parts for any of these units. Took a while to get a supply chain network for these new bearings

215k pinion bearings are plastic ball type and the race has a much larger OD; my guess is that bmw did this for fuel economy reasons- they are for sure not nearly as durable as the old 210mm pinion bearings (all metal, also much cheaper new)


If you want to use a 330d unit just adapt the entire chunk to the crossmember. Easiest way

Bmw also did the same thing with the 188mm

188mm classic-> 188k kompact-> 188L kompact with large diameter pinion bearing race set; stupid plastic bearings also and no input pinion flange.

[moroza]

Digesting...