m30 diff 4.10?

[beefy]

hi all

Im hoping to be running the standard 318is diff (4.10) with my m30 as at present i cant afford a better diff.

Reading on the de site it says that this diff will make 1st gear useless and that normal tyres will be no good with this ratio.

Whats your opinions on this?
Is any one using this ratio or have any experience of this ratio?

[ric325i]

here is my opinion.

i have that dif on my m30 and its dirt box.

1st gear is only for parking, i tend to use 2nd most times to start as 1st is over before i start.
in 1st the car wants to move fast and takes plenty of clutch control.

5th is like 4th so on the motorway it just uses way too much fuel revving too high.


but on the strong point if you can get grip to get you too the 120mph top end it does it in good time
plabt your foot and you will spin most the time but in honesty if i didnt have to do motorways i would really enjoy the dif.
i can step the back end out with NO problem in 2nd.

the dif is fine but you will feel you are missing something. and thats my 1st hand experiance

[Toby_Unna]

get a 3.64, at least as a temporary measure.

you'll soon save the £40 odd quid in reduced fuel costs

as ric says 1st will be less than useless and 5th will feel like 4th - so you just end up with a four speed gearbox

[ric325i]

i will be getting my 3:71 (or something) from home next week as i it will make loads of sense.

you should just get hold of a open dif for now as it will annoy you!

[gareth]

small case diff with a M30 is a no-no

see my sig pic below for the first and last time it tried to use one on mine all it took was a lot of grip, smooth (no violence) launch at 1500rpm and it absolutely shat itself!

if you can't currently afford a decent 3.64 or 3.46 LSD, get hold of an open medum case one (325i) as it will be at least a 3.91 (still too low) and won't go bang!

regarding ratios, i've had a 3.64, 3.72, 3.91 on mine and it felt best with the 3.64. ieally a 3.46LSD is the one to have but they're rare

http://www.e30zone.net/modules.php?name ... ic&t=80352

[beefy]

i feel ive got to try it with the 4.1 if it goes bang do you have bits of diff basing flying every were or is it just the internals that go.

Am going to be on the look out for a cheap diff tho

[gareth]

mine siezed and locked both rear wheels immediately. luckily i'd not got far and wasn't going very fast!

[beefy]

thats defo a no no then.

Ill find a diff if i dont get one im time ill just take it easy

[gareth]

i tried to kill mine on the road but it went at the pod!

i personally wouldn't bother even using it for a bit.

as / when it goes, you won't be able to tow it home either.

[ric325i]

yeah since my 335 is off the road right now i will be changing the dif as soon as i pick the parts up then trying to put it back on the road.

if it went bang on the exit of a corner then it would be game over.

all that torque has to be released somewhere, its just a good job i have very poor tyres on my 335

[alan335i]

i've got the standard 325i sport lsd in mine (3.91 i think),running with 17"s on its doing 140mph(not that i've tried) top end and 0-60 in just under 6.5sec, it can give a e36 m3 a good run for its money in lift.

[whipsey]

all that torque has to be released somewhere, its just a good job i have very poor tyres on my 335

i currently have 12 spare tyres for when i finally manage to do my conversion

[dannyboy759]

So what would an M30 be like with a 3.73 or a 3.91 ie standard 325 diff?
Thats what i plan to use!

[DRIFTBOY]

It depends what you are after really.

I'm using a 3.73 in mine and it's not too good for motorway cruising.
It will get an indicated 140 on the clock quite happily though.
When I first got it on the road I did reach for a non-existant 6th gear a few times!
I usually pull away in second gear as first is almost useless!

But acceleration is prety good.

Swings and roundabouts really.

[gareth]

a 3.91 is utterly pointless at low speeds. however, i did manage to reach an indicated 142mph uphill the other day before it hit the limiter!

ideally, 3.64 or 3.46. i'm building up a 3.38 but i've got very low profile tyres which affects the gearing

[dannyboy759]

3.64/3.46 large case diff, i take it one from a compact wouldnt last too long!!

[leedg]

Will any size diff fit any car? or are the subframe mounts different between sizes? I have a small case diff but need to swap it, can i just get a diff and driveshafts? Or will i need the full subframe?

[beefy]

Is there any difference in prop lenght between small and medium case diffs, i ask because i have a small case on my car now just wanted to get the prop shaft made up as soon as possible.

[gareth]

the mountings for E30 small and large case (small and medium case in BMW terms) are the same.

to swap between the tow, the only thing you will need to do is adjust the prop length at the sliding coupling. it's only about 10mm difference between the two

[leedg]

cool cheers

[MJG]

On my e28 I had a 4.1 diff with the 3.5 engine and standard 525i getrag 265 gearbox. I LOVED the gearing. I did have 225/45/17s on though so my top end was more than 120mph. In fact iirc it was about 140mph on the limiter. Anyway, THAT felt great.

1st gear was fine, it's just that 2nd gear pulls just as hard. The car was stupidly fast. Pulled hard on my friends mr2 turbo with circa 250bhp, and pulled hard on a friends 260bhp s13, also smoked a pulsar GTi-R on the motorway. But then again that's in an e28 which was probably about 1100kgs, so in an e30 the 4.1 diff would probably be too short.

[MJG]

On my e28 I had a 4.1 diff with the 3.5 engine and standard 525i getrag 265 gearbox. I LOVED the gearing. I did have 225/45/17s on though so my top end was more than 120mph. In fact iirc it was about 140mph on the limiter. Anyway, THAT felt great.

1st gear was fine, it's just that 2nd gear pulls just as hard. The car was stupidly fast. Pulled hard on my friends mr2 turbo with circa 250bhp, and pulled hard on a friends 260bhp s13, also smoked a pulsar GTi-R on the motorway. But then again that's in an e28 which was probably about 1100kgs, so in an e30 the 4.1 diff would probably be too short.

[tomson]

As BMW decided to give all 535i's a 3.64 Diff then surely i would go with their recomendation....

[tomson]

As BMW decided to give all 535i's a 3.64 Diff then surely i would go with their recomendation....

E34 535i's that is.