M3 Muscle

I started my build last December, and haven't got to the engine swap yet. I figured that i would post this now as some people might like to see the progress.

It is a '92 BMW 325is that I plan to auto-x and hit some semi-local track days with. My goal for the final weight is ~2350 lbs. When I'm done it will have a LS1/T56 and a Cobra aluminum 8.8" IRS differential. I am currently finializing my cage and working on the Corba diff swap.

BMW Build thread

rao

iTrader: (18)

Nice! It is the other end of the spectrum from mine.

I hadn't seen your build thread at bimmerforums; I never go into that section.

Skele4door

iTrader: (1)

I agree, nice build man. You really need to install a camera mount somewhere on that cage facing out the drivers side window for whenever you take it out on the street. The look on the first cops face that pulls you over and sees the caged/gutted interior will be priceless

M3 Muscle

This whole project started just like yours. I wanted to do a LS1 in my M3, but I time got closer to start doing stuff I couldn't tear apart the M. It just kept growing more and more out of hand from there.

I followed your build. Very nicely done sir!

monger

nice work, any cliffnotes on the 8.8, or is that not finished yet?

M3 Muscle

Not finished yet. I should be finishing the cage in the next week or so, and then that is the next area of concentration. I will post all the drivetrain related pics in this thread, so you don't have to sort through pages of stuff some might not care about.

Project GatTagO

iTrader: (7)

Check out the Explorer covers for the 8.8" Very similar in mounting to the original BMW rear. Might save you a ton of work.

Andrew

M3 Muscle

I've looked at them. Closer to the style that I need, but nothing lines up. I'm trying to use the stock BMW differential mounts in the rear.

M3 Muscle

Here is a quick-and-dirty run down of the differential swap up to date.


Stock differential and rear subframe





Comparison pictures of the Cobra differential vs the stock BMW diff











Cut off stock mounting points on Cobra diff so it will fit in stock subframe









Removed the stock front mounting bracket on BMW subframe









Pictures of Cobra diff setting in subframe











Starting to make mounts on new diff

M3 Muscle

Machine work done on rear diff mount







Detroit Truetrac gear driven limited-slip differential

cast iron

What are you planning on running for suspension / control arms? Car looks like a wet dream!!

M3 Muscle

All the suspension/cage is detailed in my thread on Bimmerforums.com The link is in the first post. There is detailed pics of everything.

I'm running AST 4200 coil overs in front with modified front control arms to correct roll center due to lowering. The rear will have AST 4200 shocks with Turner Motorsports lower control arms and spherical bearing everywhere.

Oso SS

iTrader: (3)

I'm not going to lie, I'm a pretty smart dude - Smarter than most of the people I come into contact with daily... But I'm at page 6 in your build thread and in total amazement at the amount of knowledge you have on just how to do **** yourself. Like the rotisserie, you didn't have one and couldn't buy one so you just made one yourself. Wow.

Skele4door

iTrader: (1)

The rear diff looks very promising. You'll probably have a significant amount of warpage to the diff cover when you weld that thick hunk of aluminum to it though. Make sure the cover has enough meat so that you can throw it on a belt sander to level it back out and avert leaks. Either way you'll probably need to do a lot of pre-heating before it's welded.

Oso SS

iTrader: (3)

Okay I just read all twenty pages. Subscribing.

M3 Muscle

It won't be welded. I'm using steel that will bolt to the differential cover mounting tabs and then bolt to the aluminum where I have machined it flat. That way I will be able to shim it or make new brackets to adjust pinion angle.

Schitzo

iTrader: (6)

I have been following your build from the start. Great attention to detail. All the best

Project GatTagO

iTrader: (7)

NIce work, but why didn't you just replicate the diff mount out of tubing that would have accommodated the Cobra rear?

Andrew

M3 Muscle

Suspension mounting points. I felt that it would be hard to make a new subframe that has the exact same location on the upper and lower control arm mounts. It wouldn't take much to mess up roll center.

M3 Muscle

3.55 FoMoCo gears to fill the diff.