Fitting a medium case diff

Fri Sep 05, 2014 2:19 pm

Hi folks can anyone tell me whats required fitting a medium case diff that currently has a small case fitted been offered a 325 lsd fairly cheap but its only the diff it comes with

Is it like the E36 where you need driveshafts and half propshaft?

Fri Sep 05, 2014 2:44 pm

The driveshafts and prop are the same regardless of the diff. The width difference is taken up by different output flanges, so as long as you get the medium case output flanges with the diff it will just bolt in. You may need to adjust the prop length at the collar nut, but you won't need to swap props.

Fri Sep 05, 2014 3:10 pm

jmc330i wrote:The driveshafts and prop are the same regardless of the diff. The width difference is taken up by different output flanges, so as long as you get the medium case output flanges with the diff it will just bolt in. You may need to adjust the prop length at the collar nut, but you won't need to swap props.

Perfect thanks for this

Fri Sep 05, 2014 5:13 pm

Hey Dave, I changed from small to medium with no problems.

Fri Sep 05, 2014 5:16 pm

Your running a 318is aren't you? Is it a 3.91 LSD?

You might be compromising the acceleration.

Fri Sep 05, 2014 6:08 pm

Sanchez wrote:Your running a 318is aren't you? Is it a 3.91 LSD?

You might be compromising the acceleration.

Most definitely. I'm running a 3.91 on mine and its great on the motorway, but feels sluggish the rest of the time. It's also a little worse on fuel with everyday driving, I'm guessing as it takes more effort to get it moving.

I'm switching mine back to the 4.10 when I get chance.

Fri Sep 05, 2014 11:53 pm

jmc330i wrote:
Sanchez wrote:Your running a 318is aren't you? Is it a 3.91 LSD?

You might be compromising the acceleration.
Most definitely. I'm running a 3.91 on mine and its great on the motorway, but feels sluggish the rest of the time. It's also a little worse on fuel with everyday driving, I'm guessing as it takes more effort to get it moving.

I'm switching mine back to the 4.10 when I get chance.

there you have it from a man who knows, if you don't have an m20 lightened flywheel then you need one with the 4.10 diff ....one of the best things i done to my m42 so your m44 donk will love it....

i'm guessing [ an educated one ] you have one though ?

Sat Sep 06, 2014 6:48 am

Yup, got an M20 lightened flywheel on mine. I fitted the 3.91 as I was doing mega motorway miles for about 2 months and got tired of cruising at 4k rpm with the 4.10. Now I'm back to everyday town driving and the 3.91 is definitely the wrong choice as it uses more fuel around town and has killed the acceleration - it's almost as if BMW knew what they were doing when they decided to use a 4.10 diff!

Sat Sep 06, 2014 10:58 am

Likewise I have a M20 lightened flywheel also in my M42 I got the diff for a really good price I'll see how if goes and if I don't like it then will sell up and pay the extra tax for an IS lsd

Sat Sep 06, 2014 11:32 am

A 4.10 LSD will be harder to find than a 3.64/3.91 etc but they are out there if you want one. Cafeful with the speedo plug, I've a speedo sensor waiting for me at bmw cause I broke a pin in the sensor rushing about changing my leaking gasket.

Sat Sep 06, 2014 11:43 am

this one came with a plug with the wires cut (has about 15cm of wire) you're welcome to have it if you want it? cancel the bmw one if it cost a fair penny have this one for free

Sat Sep 06, 2014 10:28 pm

Dave, I'll come get the plug but it's the actual sensor that snapped a pin but that's cause the wires too short. Text me when your free tomorrow and I'll come round.

Sun Sep 07, 2014 3:17 am

15 cm was a bit over exaggerated has about 15mm lol welcome to it though if you still have my number gives a phone should be in all day hungover a‘a

Wed Sep 10, 2014 1:45 am

Today I did this

I had to make a completely new wheel arch lip. It's almost fully tacked on and doesn't look pretty at the moment, but it will do. Will hopefully have finished the repairs to the inner arch by next week.

Wed Sep 10, 2014 10:29 am

driftwood wrote:Today I did this

I had to make a completely new wheel arch lip. It's almost fully tacked on and doesn't look pretty at the moment, but it will do. Will hopefully have finished the repairs to the inner arch by next week.

Well that's a bit random for this thread.