bmwe21.net forums

Hi all

I'm planing to do a m60 conversion,everything thing seems pretty simple to fabricate and do apart from choosing the right diff to take the huge amounts of torque from that v8.what would be a suitable diff for the conversion?

James

E12 ''sideloader'' seems the most obvious choice. They're pretty much bullet proof.

Does it matter which model the diff comes out of ?

The sideloader conversion still uses the E21 driveshafts, I believe these are a bigger weakness than the E21 diff. Many more people have done driveshafts than diffs. I would choose either a complete E28 rear axle or a
E28/E30 medium case diff conversion (better availability/choice than sideloaders) on the E21 rear beam/trailing arms with custom driveshafts.

Which e30 model would have these medium case diffs?

Google is your friend. http://forums.eurocca.net/showthread.ph ... -is-an-LSD

I would look into costs for custom driveshafts first - they might be prohibitive and influence whatever decision you make on diff.

Jameslc wrote:Which e30 model would have these medium case diffs?

6 cylinders generally speaking - 323i's and 325i's, but they're all so old now you can find 4 cylinders with them too at times.

e28s also have the same diff, just with different rear cover and output shafts.

You need to look at your gearbox ratios and then look at what final drive options would suit best for both acceleration and motorway driving. E12 side loaders only came in few ratios and the lsds only in a 3.07 iirc I'm pretty sure that's what I've got but you can with some modification swap the pinion and ring gear out from a non LSD diff. The major reason people use e12 diffs is because you use e21 shafts so it makes life easy but e21 shafts are weak so if you're going to have to replace them for custom made you're no better off. Custom shafts will cost around £400-£500 the pair.

Personally you need to look at what ratios are most suitable first, then work out what's going to be easiest to get with a slipper and the overall cost.

The gearbox i have got for the conversion is a 5 speed manual out of an e34 530i and the diff ratio that car used is 3.07,3.15 and 3.23 and top gear is 1.01 to 1.so somthing around a 3.00 ratio diff ?

james

http://translate.google.com.au/translat ... CDMQ7gEwAA

Jacko wrote: Custom shafts will cost around £400-£500 the pair.

Do you know anywhere? Only place I found had minimum quantity and wasn't cheap either.

My shafts cost 370+vat each then you have the cost of CV's and boots on top. My total came to £1216 for the pair complete.

All Gear Services was the company.

Ben

Try the below, when speaking with companies that had stands at motorshows the general pricing seems to be around the £200-£250 mark each. I haven't taken it further as yet as i've not need to.

http://www.3jdriveline.com
http://www.brandmechanicalengineering.co.uk
http://www.cpsdrivelink.co.uk
http://www.berrisford.co.uk
http://www.ptiltd.co.uk
http://www.wilsondriveshafts.co.uk
http://www.reco-prop.co.uk
http://www.davemacprops.com
http://www.driveshaftuk.com

Thanks everyone I have got an idea on which diff I need and what ratios