LSD info wanted

[Raj_p]

I am interested in Spadge's LSD for sale, but im not sure what the ratios mean, whats the difference between them???
what is going to keep my car going in a stright line??

any advice appriciated

Raj

[SPADGE]

Why not just ask me
What car is to go in?
The ratio is basicly how many times your propshaft has to turn for the wheels to do one revolution. For example if a diff is a 3.64:1 the propshaft will turn 3.64 times for each rotation of a wheel and a 3.73 3.73 times etc etc..
The higher the number the quicker you'll accelerate but this acceleration will come at a slight loss of top end speed.

[Raj_p]

sorry Spadge, i didnt want to spam your thread.....

its going into a 320i se coupe

[SPADGE]

sorry Spadge, i didnt want to spam your thread.....

its going into a 320i se coupe

No worries mate.
You should have a 4.10:1 diff at present which basicly means that mine will lose you a little on acceleration but will gain you a bit on top end as well as improve your mpg a little as the car will be reving lower at a given speed in all gears.

[Raj_p]

Cheers for that Spadge, ill raid my mrs account to check the funds... and ill let you know

[Bob_S]

basically a 3.64 will kill any acceleration you thought a 320 had. Your best waiting for a 3.91 or a super duper rare 4.1 mate..

It doesnt sound like much but .17 of a turn makes one hell of a difference! a 4.27 diff off a 316i will make a 318is fly.. likewise with the 320i just the revs will be a bit higher

[ed325i]

Diffs for 320i 1982 to 1991.

3.45 until August 1985,
3.91 september 1985 onwards along with 4.1 option.
from september 1987 4.1 and 4.45 auto. 4.27 on some manual Tourings

You should have a 4.10:1 diff at present

??? Thats not on any list I have.

[ed325i]

What was a 3.73:1 Limited slip diff fitted to ?

[Chris-W]

Diffs for 320i 1982 to 1991.

3.45 until August 1985,
3.91 september 1985 onwards along with 4.1 option.
from september 1987 4.1 and 4.45 auto. 4.27 on some manual Tourings

You should have a 4.10:1 diff at present

??? Thats not on any list I have.

It's on your list above?

[Ant]

325i manual, normally only see that ratio on 4 door saloons though. pre and post facelift.

probably the best all rounder ratio out there for us.

[SPADGE]

Diffs for 320i 1982 to 1991.

3.45 until August 1985,
3.91 september 1985 onwards along with 4.1 option.
from september 1987 4.1 and 4.45 auto. 4.27 on some manual Tourings

You should have a 4.10:1 diff at present

??? Thats not on any list I have.

It's on your list above?

Lol i noticed that but couldn't be arsed to comment

[SPADGE]

325i manual, normally only see that ratio on 4 door saloons though. pre and post facelift.

probably the best all rounder ratio out there for us.

Are you talking about my 3.73 Ant?

[Chris-W]

Lol i noticed that but couldn't be arsed to comment

Ah, but you just did!

[ed325i]

Diffs for 320i 1982 to 1991.

3.45 until August 1985,
3.91 september 1985 onwards along with 4.1 option.
from september 1987 4.1 and 4.45 auto. 4.27 on some manual Tourings

You should have a 4.10:1 diff at present

??? Thats not on any list I have.

It's on your list above?

Thanks chris

[Chris-W]

I've dumped the daft, provoked or otherwise, stuff.

Play nice chaps.

[fastdiablo]

sorry to hijack this thread BUT i've got a 325 manual touring and not sure if i've got lsd or not. read loads of threads and all say about a tab with the id number having an "s" in it.

While i had the car in the air at the weekend i had a look to see what i could find. There was a tab attatched to a bolt at the top/rear of the diff but this was totally rusted and couldnt find a number ?

Also, with both the wheels off the ground and in gear, if i turn one wheel the other turns in the opposite direction.

Is this lsd and what ratio should it be if its the standard diff ?

Thanks for any help !

[BMracing]

fastdiablo thats not an lsd if the rear wheels turn in opposite directions.

[fastdiablo]

Bugger ! didnt think so

If i was to change which ratio would be best ? Top speed is not really important, more into having fun and poss trackdays

[Simon13]

my alpina has a factory fitted 3.73 lsd and it's a 2 door. It's defo the rarest of the the ratios for a 325.

I thought........all facelift manual 325i saloons 2/4 door had a 3.73 diff/ LSD or not. Auto saloons had 3.64. All tourings/sports had 3.91's whether they were auto or manual. Chrome bumper wagons bar the sports had 3.64's too.

Cabs i don't know about!

[BMracing]

Our 4 door 325 is a facelift and seems to be geared exactly the same as my phase one 325 sport. No idea what the ratios are but i have a vid here of driving the 4 door flat out showing when i change gear (was a bit early into 5th). It had standard wheels at the time.

[fastdiablo]

my alpina has a factory fitted 3.73 lsd and it's a 2 door. It's defo the rarest of the the ratios for a 325.

I thought........all facelift manual 325i saloons 2/4 door had a 3.73 diff/ LSD or not. Auto saloons had 3.64. All tourings/sports had 3.91's whether they were auto or manual. Chrome bumper wagons bar the sports had 3.64's too.

Cabs i don't know about!

So the way im reading this, if i havent got lsd at the mo, im best off changing it for a std ratio 3.91 for fun and trackdays ? . . .

[Simon13]

it's the best diff for acceleration yes.

A 325i tops out at 137mph quoting the bmw press for speed for a sport, which has this diff fitted

[fastdiablo]

thanks Si for making it clear, next on the agenda then is to source one . . . anyone got one for sale ? ? ? . . .

will post up in parts wanted . . .

[ed325i]

Diffs for 320i 1982 to 1991.

3.45 until August 1985,
3.91 september 1985 onwards along with 4.1 option.
from september 1987 4.1 and 4.45 auto. 4.27 on some manual Tourings

You should have a 4.10:1 diff at present

??? Thats not on any list I have.

It's on your list above?

Just to clear things up I did know if the 4.10:1 was the same thing as 4.1:1 That is why I asked.

[Weeman]

How easy are 4,27 diffs to find, the making a 318is fly comment has made me damp

[320Touring]

How easy are 4,27 diffs to find, the making a 318is fly comment has made me damp

My 320i touring has a 4.27 open diff.......

[anisotropy]

Not easy, try ebay.de I got one for about 230 quid, haven't it fitted yet though. They came on 318 convertibles or something (in small case form)

[Bob_S]

anisotropy... I hope thats an lsd at that price!

4.27's can be found on 320i tourings, 318i and 316i tourings and normal 316i 2 and 4 drs an lsd varient is quite rare though but still dont fetch any more than £250 or shouldn't do. normal open ones are obviously ten a penny.. you can always get a small case lsd and get the 4.27 build onto the lsd unit

[ed325i]

How long do LSD's last before they need a rebuild ?

[Bob_S]

i heard about 10hrs i believe?

[Chris-W]

10 hours of lock up, yes.

[ed325i]

So most will need a rebuild by now ?
How come its in hours not miles ?

[320Touring]

So most will need a rebuild by now ?
How come its in hours not miles ?

going sideways with a locked diff means doing less miles than the wheels appear to be travelling.

similar to tractor engines that work in "hrs at xxxxrevs" due to them being used to drive other machinery whilst still/

[Chris-W]

And boats, he added helpfully.

[Bob_S]

similarly a routemaster bus