E30 Zone

i have 2 spare lsd's in my garage,

ones a 3.91 ratio
and the other being a 3.64 ratio

which ones better? the 3.64??

thanks max

hi again, think it depends on what you're after.. the 3.64 will give you more top speed i think but the 3.91 better acceleration??

It depends in what your going to put them into, what engine size is the car.
Oh and if their spare mate, i'll have the 3.64 cheers

lol, i want to put 1 in a 318is. ive got exactly 10 people pm me about these diffs, sorry there not for sale people,

3,64 would make an iS a total road block. 3,91 if you have to, but ideally you want a 4.1 or higher.

sod it then, will get kevo to re-con 1 of my 2 broken 318is lsd's i have.
3.91 is now sold £250,
i am keeping the 3.64 for my next 2.5 rally slag.

3.64 is a good diff for the M30 conversion

Its probably the best plan, you'll have a 'new' diff that will actually lock. You could go higher on the FD too, to make it a bit more zippy by obtaining a 4,27 small case off a touring/cab 318 iirc.

Depends on what you want?

i just want it even, a good acceleration and a good top end, the diff i got in at the mo is brilliant for top end.
can this be done?

You can either have one or the other really, not both. You could muck about and change the 5th gear, but that all gets a bit sad, which is the only way of shortening the acceleration whilst maintaining a cruising gear.

I doubt you can top an iS out with the factory diff in fifth, as I suspect it doesn't have enough power. This is what you mean when you say 'a brilliant top end' right? Or do you mean less revs so better MPG?

how much a difference would there be between the 2 diffs? how much would you lose top end or gain in acceleration?

i think i will stick with top end really, i like sitting behind a few mates in there 325's down the motorway lol,
think i gotta pm kevo to ask prices! anyone know anyone elses that does diff rebuilds?

i dont know the mathimatical calculations, but between the 2 diffs i have (that actually arent broken) there is definatley a difference, you really notice the acceration on the other one i have.

the only way an m42 will hit the lmiter in 5th is if a 24v is pulling it

Just for a definite answer on this, what noticeable difference in the drive will a 3.91 make, as i have a 3.91 lsd here to go into my non lsd IS. I'm taking from this thread it will make the gearing slightly taller on final drive

yes, according to these zoners!