E30 Zone

Hi guys, probably been asked a million times but i've searched and can't find anything.

Will a 318i diff fit a 325i?

Any issues, pitfalls, problems?

I want to get the 318i diff welded up and i prefer to have my 325i one open for when i want to swap them back and forth.

Cheers

Read this mate:

http://www.e30zone.net/e30zonewiki/inde ... fferential

ahhh great! Thank you! I missed that.

Skimming through, seems like it is possible then, may require the prop length adjusting but that car apparantly be done under the car....unless i have read wrong and have it all back to front?

Car will be used daily and given plenty of beans, so i want some reliability but the 318i one has been offered cheap and it's something that tempts me....i just don't want to get into spending £££ to fit a cheap part, and then have it blow up first time i floor it

318i diff will be small case, and will probably be destroyed by the torque from the 2.5 engine.
The welded diff. will also be illegal to use on UK roads, as it will invalidate your insurance.

Destroying it was my biggest worry....might have to go back to the drawing board, or just pull the current one out and weld that. Ideally i want a fit and forget job.

LSD for fit and forget.

I have a few mates who have run welded and/or small case diffs with 3.5 M30's and been fine for tramp drifting. All small budget bodgery stuff in the name of a laugh

Depends how seriously you take life, I'm not suggesting that you do the above by the way, I wouldn't do it.

E30's make excellent drift cars but the purists get upset about it

depending on condition it should be ok for a while - I've destroyed a small case with m40 power and I'm very mechanically sympathetic - they're pretty weak in the first place.

I'd imagine as the mechanism is smaller, there's more load on the internals, but then welding it would probably strengthen it up a fair bit - you're taking all the strain off the the planetaries which are the bits that disintegrate.

If you're planning welding one it's possible it can be done in situ, but if you were going to take it off anyway, I'd be tempted to fit the welded small case - they are noticably lighter & throw away bucks.

Duke- Yeah mate, i have definatley picked up on drifters being "hated on", on here haha....but i love the cars and think they are an ideal base for what i want to do......E30's have dominated European Drift Contests for years, so they must have something going for them.

I've encountered purists in a few cars scenes. It's all normal i guess, but i won't be trying to appease them; purists never seem to have as much fun as others to me...cars have to be about the fun factor or you're doing it wrong, and i pay the bills on my cars, so i'll be making the choices

I don't rate the BMW LSD options personally, and to buy a real nice one it's essentially a fair chunk of money that could go on petrol, tyres and seat time. I am 100% going welded diff.

Barx-Yep, this diff is the price of a pint!
I am tempted to do it as a mechanical experiment to see if it takes it or changes the acceleration.....or, if i do bottle it, i'll have it for spares, chuck it into a box and take it with me on days in case mine fails. Then i can quickly fit it and limp the car back home rather than be towed.

In answer to your initial post, yes it can be done then mate

Good luck with it all

if it's as cheap as a pint, I'd definitely not be welding the med case up, a diff can be swapped in 2 hours..

if you're going from a 3.64 to a 4.x it will be noticable, have a play with this:

http://www.unixnerd.demon.co.uk/revs.html

gearbox ratios are on the wiki I think

Nice link Barx ^^^

Duke- Thanks for the help mate

Barx-oooh, good stuff! Thanks, i'll have a look now, not interested in top end, acceleration and a lively back end is all i want...i've been told mine has a closer ratio 'box in it?? (I'm on a steep learning curve with modified BMW's at the moment. Had my E46 for a while, but my knowledge is more Ford and Japanese based)

A medium case diff is going to be more than the price of a pint agreed, but it'd hardly break the bank! I wouldn't bother putting the effort into welding and fitting the weaker diff, just to have to re-do it... But then swapping diffs is one of those jobs that I've already done more than enough times thankyouverymuch!

My intital worry was that it wouldn't be strong enough and that there would be X,Y,Z parts that i'd have to buy and fit to make it work.

Now, i'm torn....do i weld it and fit it as an experiment? Or Buy it, keep it with all my spares and weld the current one? It's one i'm mulling over. The sensible side of me says that i should weld the medium case, the curious side of me says weld the small case for giggles and an experiment....never know for sure until you try 'n all that.