3.38 Diff

[Davenotouring]

When I removed the diff from my 325i Touring, with help from Demlot, and took it to a specialist to fit, because I didn't have time to fit, despite offers of help from Ian332 which I couldn't take him up on due to limping car, they actually fitted a diff from a '96 318ti Compact.

The reason was that my existing and broken diff was small case, and the 325i Touring one was large case, and it would have been more work!
It's not that it's really a problem, but I am getting more miles to the gallon, and acceleration is better if anything. It's not slower for sure.

The diff is apparently a 3.38:1 This is super low!

[Jhonno]

well technically its high...

low would be an auto's 4.4....

Thats why your getting better MPG as you need less revs etc.. its prolly quicker as you dont have to change gear as often and your making more use of the available torque

[Davenotouring]

It says in power band for longer yeah, but then has to build up to it for longer in the next gear, so I guess it's a balance.

Higher ratio? Sure?

Explain.......

As in it takes less turns of the prop for a turn of the wheels?

[Paul325i]

It is a higher ratio, they work the other way round, the closer it is to 1:1 the higher it is, the further away the lower.

[Jhonno]

yeah as Paul says

[johnono]

iԚ´m tottally baff wiyh the diff stuff , is is

the first three numbers on the "diff tab" stipulate the ratio,

if so, what differences are there in a

high diff or low diff?

i lookes at a 325Ԛ´s today and i read 315 on the plate at the back, im sure i read wrong as ive not seen these numbers mentioned before

also what driving caracturistics can i notice from inside the car?

ive tried to throw it out in wide corners ( saftley mind ) but she will not slide out....not that im complaining

cars a m20b20 touring 90

[Jimbob]

3.15 is found on an M3 as far as I know, and an S at the start makes it a slipper.

[johnono]

is there a list of different ratios and their coresponding cars?

[E30Adam]

The reason was that my existing and broken diff was small case, and the 325i Touring one was large case, and it would have been more work!

I don't understand why they told you it would be more work, it's a simple replacement and all you need to do is knock the prop back an inch or so which takes 2 hits of a hammer.

I swapped Jimbobs small case diff for a large case diff and it was a direct replacement. Easy. Sounds like they wanted to sell you a diff they had lying around.

[Davenotouring]

It does sound a bit like that, but they said upon looking at it that they would have to drop the exhaust down to do it.

Whether or not they were fobbing me off I'm not sure.

But they straight swapped the diffs and they had no idea if my 325 one was ok and they trusted me when I said it was.

I can't complain, because this one is silent as they come.

[Gunni]

is there a list of different ratios and their coresponding cars?

Yes there is

http://www.schwarzfour.de/e30/fotost/f00023/f00023.htm