Turbo bmw e36 stock differential to 750il diff conversion

[jgcm3]

Hey there all. Been working on another solution to hold more power in our turbo e36 cars, and wanted to share our progress with others who might be interested... It is a complete differential swap from a 750il v12 car and features the bigger 210 ring and pinion (same size as the euro e36 diffs which we unfortunately did not get) but with a 3:15 gear ratio, unlike the 3:23 in the euro diff. I believe the sport versions of the 750il diff have 25% LSD, which is also a plus. Fitment bolts directly up to stock e36 halfshafts and 6 bolt driveshaft, and can be also combined with high hp driveshafts and halfshafts as well... We had to modify the stock subframe by removing the front bushing that fastens the stock driveshaft in place (the notorious bolt that breaks all the time)...and fabricated a new bracket to hold the 750il diff in place. We haven't tested all the specifics yet, but it should hold much more power than stock diffs, which notoriously break their teeth at the dragstrip... Final product will be powdercoated black and will come with two M14 bolts that hold the diff in place. Below are some pics of the overall progress...

Best Regards,

john@cesmotorsport.com

[MrBlonde]

E36 M3 with 3.0 litre S50B30 had the 188 diff.
E36 M3 with 3.2 litre S50B32 had the 210 diff.

E46 M3 have 210 diff.

[jgcm3]

More pictures of the overall conversion... Subframe with bushing removed to make room for the new diff... before and after... also, Comparison shots of the 750 diff versus stock...

[Shuasha]

Cool project, maybe I have a use for my extra large case 3.15 LSD afterall!

Also, you need to be a supporting vendor, talking about product releases crosses the line.

[jgcm3]

more pictures of the 750 diff going back into an e36...

[jgcm3]

Here are the bracket pics and how it fastens the 750 diff to the subframe...

[jgcm3]

Cool project, maybe I have a use for my extra large case 3.15 LSD afterall!

Also, you need to be a supporting vendor, talking about product releases crosses the line.

Thanks for the + response!!

Just giving some info and showing what we are up to. Haven't talked about pricing or anything. Hopefully moderators will agree this is a post on a good project that people will be interested in? People can come check us out at our website if they are more interested. THanks again... Also, open to feedback so post what you think

[zemaestro]

I did the conversion last winter, Mine works great...

[Shuasha]

Here are the bracket pics and how it fastens the 750 diff to the subframe...

Wow, no bushings on the front mounts? Should be interesting, and probably worthwhile for a track car.

[flipppalot]

Subscribed

[M52 POWER!]

That's freakin awesome! I would suggest using solid aluminum bushings on the rear of the adapter plate you made. Since the front 2 bolts are directly mounted you will not want them to be bending left/right from the rubber bushings flexing. This could overtime weaken the metal until it fails.

Besides that, good work. How/where did you have the adapter plate made?

Are there any clearance issues with the rear swaybar?

[MrBlonde]

I did the conversion last winter, Mine works great...

Yep, did it in 2004 and zero issues.

[BadBoostedBmwM3]

Nice to see.

[jfdmas]

I wasnt aware of a weak diff issue. hmmmm Thats a part that i havnt broke yet.

[DADx2]

I am interested in this information too.....subscribed to learn more

[jgcm3]

That's freakin awesome! I would suggest using solid aluminum bushings on the rear of the adapter plate you made. Since the front 2 bolts are directly mounted you will not want them to be bending left/right from the rubber bushings flexing. This could overtime weaken the metal until it fails.

Besides that, good work. How/where did you have the adapter plate made?

Are there any clearance issues with the rear swaybar?

We designed it based on the mount points of the 750 diff. It actually has three mounting points, but only two are easily accessible when in the stock subframe. Made the bracket at a custom fab shop with a water jet, and is a two piece design. Agree about the solid bushings, but decided to use stock components for now to test them out, and its was just the easiest setup to do first. Also wanted to test vibration differences with this solid mount bracket in case it was too much and we need to do bushings instead.. I think most will not care since it can hold so much more power... No issues with swaybar clearance...

Next step... beat the heck out of it

[mike radowski]

Looks good. I did the research but I haven't broke another diff since I started thinking about swapping to a 210 diff. That is the next route I'm going to take after another failure. What model years are the sport packages offered?

[S50B30T]

Subscribed

[turnerNCM3]

Can't wait to check it out in person. I need to come hang at the shop soon!

[jgcm3]

Looks good. I did the research but I haven't broke another diff since I started thinking about swapping to a 210 diff. That is the next route I'm going to take after another failure. What model years are the sport packages offered?

Thanks Mike R. I follow alot of your work on the forums (topnotch stuff!) This diff is out of a '92 750il. Chose it because stock halfshafts and driveshafts bolt right up to it with no modifications... I'm pretty sure they can still be purchased new through bmw with the sport package that includes the LSD during those years, but I need to do a little more research. Planning on building it up once initial R&D is done. Going to do a bunch of road testing to see if the design works good, and if it exposes more weak points that need to be addressed... Eventually, I'll probably add a high hp driveshaft and halfshafts, but for now, just going to see how much the stock components will handle... and then go try and stand the thing up at the track

[daytona M3]

i bought a euro m3 3.2 210mm diff from a member off ppf forum,i have seen them for sale on ebay germany for around 800usd

[turbojunky]

this is good info

[jgcm3]

i bought a euro m3 3.2 210mm diff from a member off ppf forum,i have seen them for sale on ebay germany for around 800usd

We actually have a euro evo subframe and diff at the shop to compare, but imo, 3:23 is not the best setup for big boosted power. Just too much wheelspin in the lower gears when starting to push 500-600+whp. Also, wasn't too keen on it having only one bolt again that holds the diff in place in the front... I'm actually a big fan of the 2:93 gear set. 145mph in 4rth! Had it on my car until i blew it up at the drag strip about a year ago. 3:15 seemed a decent compromise to be able to use a bigger 210 ring and pinion... and you can find these used relatively cheap $250-$350.00... I'll be posting more results as we do more testing/beating on this setup

[MtechNick]

Looks good. I did the research but I haven't broke another diff since I started thinking about swapping to a 210 diff. That is the next route I'm going to take after another failure. What model years are the sport packages offered?

need a test car mike ?

[mike radowski]

Do any of these diffs come with a ~2.9X ratio and an LSD?