M235i Differential Upgrade

Dumaurier7

Lurker
May 19, 2020
18
Hello all, I am fairly new to the board, have been here reading a lot before I decided to post! I own a European M235i with all the FBO stuff, MHD and XHP flashes, port injection with SS controller, PR coil upgrade and PR LPFP upgrade. At present I am in the process of completing a custom big turbo setup which features a custom SS tubular exhaust manifold, BW8474, Turbosmart dual Recirculation/Blow off valve and CSF dual pass radiator (needed to allow thermostat relocation).
So after my lengthy introduction, on to the issue/question at hand! After spending time and money doing all the above modifications I'd like to be able to put the power to the ground so I started looking at LSD's for the F22...….they are ridiculously expensive and all the shops require the unit to be sent in! why is this so? is the F22 diff. different to all the rother BMWs in some way? in my time I have built a few diffs without issue, why does this come across like some closely guarded black art? why isn't more information available for the DIYer? I am located in the (sunny) Caribbean so shipping diffs back and fort isn't a first or feasible option, I'd much rather get all the parts and do my own machining and rebuilding, why doe this seem so difficult to do?
 

Dumaurier7

Lurker
May 19, 2020
18
Waw! 802 views and no responses? guess I'll be the first person to eventually do this then?! In the interest of destroying the attempted monopoly by the aftermarket I'll be sure to post a detailed account of the process and my experiences.
 

scrllock

Sergeant
Dec 17, 2018
257
Getting your lash set correctly and dealing with shims, bearings, etc. is something most people don't want to DIY. I've spoken to performance shops that won't even touch the inside of a diff.
Not sure what you mean by monopoly, you can order one from mfactory for $1k and I'm sure they'll send you machining specs if you ask, though they won't honor their warranty without professional install.
 

Dumaurier7

Lurker
May 19, 2020
18
Getting your back lash correct is a simple and basic procedure once the correct tool (dial gauge) is used, this was done by mechanics an DIYs s way before advent of the internet and online shopping! this procedure has not changed! In fact it’s made even more available due to the very same internet and online sites like YouTube.
I refer to it as an attempted monopoly because some sites (diff lab) don’t want to sell you the parts required or even give you the model number for the LSD units so that you can search for them elsewhere, also the actual procedure for removing the welded ring gear is hyped as such a difficult thing that only specialized equipment and highly skilled people can do it! That is BS! Anyone who can operate a lathe can do this job and correctly shimming the RG is a matter of simple arithmetic. These vendors profit by instilling fear and ignorance and limiting access to the correct parts but a bit of searching will teach you a lot and help you find the parts and CHEAP tools required !
 
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