M52 2.8 diff ??

[sk8parkstu]

Hi, I've just got a 318i touring with an m52 2.8 engine and five speed box. The diff is the 318 diff and I'm not enjoying it, I've been trying to look for the best ratio to make something like a normal road car. Any help would be welcome

[daimlerman]

You using the ZF 'box with direct drive 5th?

If so,you need a diff ratio around 3:05-3:25.....

This sort of ratio was stock on E30 M3,but widen your search to include the smaller engined E28 models.
You need a medium case diff,8 bolts on the rear cover.
Ex E28 diffs are not a direct swap,you need an E30 type rear cover and output flanges.

[sk8parkstu]

Cheers, I'll start hunting something down

[AardHawk]

The 525e used a 3.09 medium case diff.

[sweep]

And 3.07 as i have one here!

[Simon13]

the gearbox type is important to know before you go getting a diff as if you used an e30 gearbox then a 3.07 diff is no good really

[Motorhole]

Also Z3 2.8, 3 litre and Z3M diffs are ideal and a straight swap, aside from perhaps output flanges. 2.8 and 3.0 diffs are torsen, Z3M are a plate type LSD. The torsen diffs pop up pretty regularly on here and on ebay.

[Andyboy]

The 3.07 or 2.93 E28 525e diff is perfect but you'll need E30 325i output shafts and a rear cover - the 318i items will not fit.

[e30rapidic]

So you have a small case diff? and is it the 4.10 ratio?

I have a zf trans with 1:1 5th and have used everything from a 2.93 to a 3.46. I currently have a 3.25 which is good for fun and not too obnoxious on the highway. I also have a 3.15 to try.

If you have a Getrag with 0.83:1 5th, the 3.73 is a good ratio.

[sk8parkstu]

I've seen a med case 3:23 on eBay, it's £200 does this seem about right ? Plus I won't have to change cover or out puts. Will I have any prop issues with it being longer ? Car has 328 prop.

[pacerpete]

I have an excellent 3.25 LSD here.

[sk8parkstu]

What do you want for it ?