E46LM7

Hi guys, looking to leverage your considerable brainpower to clarify some things for me. I assure you I've done research and honestly this is the first time I've asked a question here because I usually can find my answer.

I'm putting a 5.3 and M6 into an E46 2000 BMW 323CI coupe. I'll be using my On3 76mm turbo so the rear end isn't going to hold up. Plus I want LSD! This is nothing impossible by any means, I could bolt in an E46 M3 rear end and axle shafts or put a Ford 8.8 in with custom CV shafts. What I'm wondering is how much budget friendliness can be incorporated while remaining worthwhile?

The M3 rear runs about $850 with unknown internals so I'd expect having to rebuild it. The Ford 8.8 is stout, affordable, and has a variety of gear ratios but as far as I know would require custom CV shafts to work. Do you guys see any reasonable alternatives or are these my most budget friendly options? Hopefully I gave you enough information. Thanks for your help!

stevieturbo

M3 will obviously be the easiest...but what ratio is the M3 diff ?

If you've access to cheap 8.8" parts, then despite custom shafts or adaptors, long term it might be the better option for you.

nmccann

iTrader: (1)

yes I know I don't post on here a lot but there's not a lot of info out there on these swaps so I'm going to toss my .02 in. I have a similar swap to what you're talking about. It's an 02' 325i with a forged 370 and a PT7675. I have a 4L80E that I built behind it though rather than a t56 like most do. Made 1K on an SF-902 engine dyno at a little over 14psi on pump 94, so it's pretty real as far as power goes.

I had the same issues as you starting out, the 188mm diff in those cars stock is pretty wimpy. I bit the bullet and bought a complete dropout from an M3. FYI though, I don't know where you're going to find a rear for $850, mine was close to $2500. The lower control arms, sway bar, cradle, brakes and obviously the diff/axles are all different than what currently lives under your car, you're best off buying the whole thing. I needed taller gears (stock M3 is 3.62) so I swapped the gears for 3.15s from an E31, my diff and stubs are also from the E31 since it's a clutch style diff. The BMW fanatics say it's not as good for the track as the stock M-Lock but neither is 1000hp in a 2wd 4 door family car lol. The rear suspension has held up 100% so far, mind you I don't run slicks but I do some stupid nasty high speed burnouts in it and hammer on it all the time. I've put probably 10,000KM on it since I got it running this spring, the whole rear is oem BMW and haven't had a single moment's trouble.