E30 Zone

well i been told it will slow my car down but by how much??
im clueless on all the ratio's of diffs and spose u lot are my best help.
a 325 lsd is easier to come by than the 318is u agree??? is it worth me fitting one or shall i just go for an open diff?? i like to do a few donuts and get the back end out on roundabouts, whats best for me???
thanks all

LSD is better.

What car have you got??

318is a 4.1 LSD would be best or even 4.27 but there rare as rocking horse poo.

325 3.91 is prefered but 3.64 is also good and will give you better economy. 3.73 is a compromise.

In terms of diff the lower the number the slower the acceleration but better top speed and the higher the number the faster acceleration and lower top speed.

4.1lsd isn't what you would call common either..

Jhonno wrote:4.1lsd isn't what you would call common either..

I was mentioning both in that sentence

they're as rare then

i have a 1990 318is,

yeh heard tht 318is lsd is rare as rocking horse poo, i cud get mine rebuilt some time, def wont throw it. but for now wanna get summin just didnt know to much bout wat a 325i diff will be like on my 318is.
ill have a phone around see wat i can source
thanks anyone else tht can lend some knowledge ill be very grateful

Jhonno wrote:they're as rare then

You can fit the clutch pack out of LSD to your diff i think or fit your ring and pinion in an LSD or something along thos lines

3.91 lsd is gonna be your best bet imo

thanks all, ill start phoning around see wat i can get.

There have been a fews guys who fitted 3.91 lsd's to 318iS's. The loss of acceleration isn't really that dramatic and if your desparate for a slipper it's the only sensible option in the UK.

If your prepared to import a diff from the states you should have a better chance of finding a large case 4.10 lsd as these were standard fit to US M3's. Or you might find one in Germany.

i've got a 3.91 slipper on my 318iS and i didnt really notice any difference at all...

And and the 4.1"s are small case remember. Meaning that they tend to break if to much power is put through them.

Wont have any problems with one of them on a 318is then....

Put a 3.91 LSD on, and if you're worried about the slight loss in accel, then put some 195/50/15 tyres on - that'll put the gearing back to normal

Lordschleife wrote:Put a 3.91 LSD on, and if you're worried about the slight loss in accel, then put some 195/50/15 tyres on - that'll put the gearing back to normal

So that's a lower profile than standard? Does that require stretching the tyres?

Conrad wrote:

Lordschleife wrote:Put a 3.91 LSD on, and if you're worried about the slight loss in accel, then put some 195/50/15 tyres on - that'll put the gearing back to normal

So that's a lower profile than standard? Does that require stretching the tyres?

no. the lower profile of the tyre will just bring the rolling circumference of the wheel down, making you accelerate faster, but then your speedo will be out slightly

maxfield wrote:

Jhonno wrote:they're as rare then

You can fit the clutch pack out of LSD to your diff i think or fit your ring and pinion in an LSD or something along thos lines

Not really, an LSD unit out of a large case diff won't fit in a small case diff as fitted to the iS.

Same with the ring and pinion gears, non-interchangeable between different casing sizes.

Cheers,

Iain T

thanks people, ur a big help

Templ8e30 wrote:

maxfield wrote:

Jhonno wrote:they're as rare then

You can fit the clutch pack out of LSD to your diff i think or fit your ring and pinion in an LSD or something along thos lines

Not really, an LSD unit out of a large case diff won't fit in a small case diff as fitted to the iS.

Same with the ring and pinion gears, non-interchangeable between different casing sizes.

Cheers,

Iain T

Thanks but can you with the same size diffs?

Thanks but can you with the same size diffs?

Yes you can.

Bear in mind that the crown wheel and pinion gear are a matched set and must be fitted as a pair.

Cheers,

Iain T

Sorry to drag up such an old thread but are E30 diff's quite interchangable? i.e. if I were to get hold of a LSD from an E30 325 sport, could I put it into my E30 318iS as a straight swap?

I think the diff on my iS is monkeyed and have seen a cheap LSD off a 325 sport for sale - wanted to know if it'd go in...?

Cheers

I put a 325 diff in mine. Here is the thread

http://www.e30zone.net/modules.php?name ... highlight=

cheers chief, i'll find out what ratio it is and maybe have a punt...

nice one.

anyone come across a 3.50 ratio LSD before? apparently this one i've seen is from a 325i sport.

would that mean i'd get pants acceleration if i put it in my iS?

Never heard of that ratio, 325i diffs are either 3.91 (facelift manual 325i's), 3.73 (usually auto's) or 3.64 (pre-facelift 325i's

Stick with a 3.91 to avoid losing much acceleration.

Cheers,

Iain T