What Diff for 1988 320i

Thu Sep 14, 2006 1:59 pm

My diff is a little noisey so I'am going to replace it can you guys tell me what the best diff ratio is to use for 1988 320i

Thanks in advance

Thu Sep 14, 2006 5:58 pm

I'll probably get flamed for this, but........
I put a 3.64 in my 320i Touring. It's improved the economy (1000 mile trip to and around south-west Scotland 33.85mpg) and it hasn't dulled the accelleration as far as I can tell.
HTH
Stuart.

Thu Sep 14, 2006 5:59 pm

3.91 for acceleration.

3.64 for decent motorway crusing

Thu Sep 14, 2006 9:16 pm

Hmmm - I put a 3.64 in my 320i and the acceleration in 4th and 5th was reduced - mine had a big bore throttle body and a chip. However once wound up it would sit at 100 all day. On my last track day at Croft I did Croft to Oxford in 2 hours 20.....

Thu Sep 14, 2006 9:19 pm

Andyboy wrote:mine had a big bore throttle body and a chip.

So's mine!

Thu Sep 14, 2006 10:40 pm

Mine's run a 4.10 fine for 10k - no signs of damage yet. It cuts into your economy on long trips, but I did find an improvement in acceleration over the 3.91 (I think!). But I only had that one because the diff was cheap with low mileage (70k compared to mine at 140k). If I could have found a 3.91 I'd have used that.

So basically, 3.64, 3.91 and 4.10 will all work, but with slight trade-offs for economy or acceleration. But I don't know if a 4.10 will have a shorter life or not. The oil's still clean after 10k, so there doesn't seem to be much wear going on yet.

Hope that helps