rear end upgrade questions.

[mattygmoe]

I have read that a nice upgrade for an "E" is a 3.25 or 3.46 rear end swap. Which is better of the two? Whats the difference? Are any other modds. needed to complete swap or is it just a bolt-in swap? Is it worth spending time and on? Thanks.

[Aptyp]

bolt it

3.46 is much more fun, but since e has less revs, it runs out of steam quicker than 3.25.

Quicker acceleration with 3.46, and you'll still be topping out at around 115.

[E30_fiend]

Your best bet would be the 3.25lsd. Its still a HUGE improvement over a stock ETA rear diff and it is also still a shorter gear ratio so you will still get good mileage and it will be a blast to drive.

[mattygmoe]

Are both options a direct bolt-in?

[E30_fiend]

yessir. All E30 rear ends are interchangeable. And even the E36 318ti and Z3s have literally the exact same rear suspension. Same training arms, same sub frame and same diff.

pretty badass

[kronus]

It's not advised to put a small-case diff (4.10 out of a 318 ) into a 325 of any sort.

You can use medium-case differentials from e28's, but you need to swap the axle flanges from your old diff, which is a quick pop-out push-in deal.

Fiend, the 318ti and Z3 trailing arms are not the same as the e30 ones. They're 5-lug specific, but since they mount to the e30 subframe, they're commonly used for 5-lug swaps.

[E30_fiend]

Fiend, the 318ti and Z3 trailing arms are not the same as the e30 ones. They're 5-lug specific, but since they mount to the e30 subframe, they're commonly used for 5-lug swaps.

true, but my point was that they are interchangeable

[kronus]

fair enough.