LS1 swapped 91 318is differential

[328iturbodreams]

Hi guys,

I just installed an LS1 and t56 tranny via the silky kit, and am wondering what LSD I should be considering with concerns of handling the power and fitment with the 4-cyl set up.

I also have an 86 325e daily driver with no power upgrades (yet). Would it be wise to switch the diffs due to it's medium case and longer gearing set up (I believe the 325e Manual is 2.93 and the 318is Manual is 4.10)? Is this a direct swap?

thanks in advance!

[SkiFree]

It'd be worth your time to go to a medium case diff. The 168mm diff is good for up for 200-220 tq. with a medium foot.

[MR 325]

Gearing is up to you. Not sure what people usually run with the T56.

Seems like something like a 3.73 would be good?

I'd definitely ditch that small case diff right away. It WILL break.

[frankie591]

Really depends on what the ratios of your t56 are. A lot of them have a .5:1 6th gear, so even with something like a 4.10 diff your top speed would be around mach 2.

Theres plenty of gear ratio calculators online, so go and put in the ratios of your trans and see what rear gear will give you your desired speeds per gear, and your desired cruising rpm.