Sport Diff in iS??

[Litespeed]

Anyone know if i can put a 325 sport diff in an iS? local breakers has a diamond black one in.... ?

[E30Adam]

You need to find out what ratio it is, if it's a 3.64 then you'll just kill the performance of your car. I wouldn't change for anything other than a 4.10 (rare as rocking horse shit) or a 3.91

[Demlotcrew]

I have 3.91 it will make your car faster.

Andrew

[gorgeee]

can the is diff be made to fit a 325
i know the ratio is too high but want it for a town car and just wana see what its like

[kevin316i]

When you say 'iS' I'm assuming you are taking about a 318iS? This car has a 4.10 ratio open diff as standard. Ideally you should replace it with a 4.10 LSD or a 3.91 LSD, but don't go any lower than this. Again ideally the diff should be the small casing type, but the large casing type as found on the 325iS will fit. The metal tab on the diff casing will show what ratio it is.

[gorgeee]

so how hard is it to fit a smaller casing into a 325?and whats required

[Demlotcrew]

Its easy. Just bolts up.

Andrew

[kevin316i]

Fitting a small casing diff to a 325i is not recommended as they are not designed to handle the greater power.

[Lordschleife]

And if you're worried about the gearing difference of putting a 3.91 on the iS, then just switch to 50 profile tyres and it'll be pretty much back to what it was.

[kevin316i]

Yes, with 50 profile tyres the gearing will be back to what is was, but the speedo will be slightly out, reading higher than actual speed. However, difference will be small.

[gorgeee]

i want the 4.10 to make my touring light on acceleration and not too fussed about top end as i only use it for town sometimes carrying load