Tubular rear subframes.

[1972fritz]

Yes it will be designed for bolt in and will come with correct adapters. For use with a medium case diff.

[M3M3]

great idea. should definitely build in the adustable camber/tow trailing arm mounts.

[granth]

great idea. should definitely build in the adustable camber/tow trailing arm mounts.

plus 1, but make them to you do not have almost remove the subframe to adjust the toe like the current product from IE

let me know tooo when done..

[Frenchee]

Yeah if it stays under 1000 I would buy one too.

Would be great for my m20 turbo car.

Lets see a finished product

[ray_]

A more descriptive subject line may generate more interest!

Cheers,

Ray

[Pancake]

Yes, definately interested, just like everyone else said price is the deciding factor. I'm looking at a full E30 rear subframe swap and this would be more... ellegant? Either way I need a beefier diff than a small case.

[1972fritz]

Yes it will be. Does anyone have a picture of the Ireland toe adjust kit?

[creede]

I'm also interested.

I think the Rob (2002haus) was working on something like this too.

[jprocket]

I am working with a machinist friend of mine on either custom axle shafts or adapters to make the axles and drive shaft work correctly if need be.

Are you planning on a "narrowed" design so wider tires/wheels or lower offset wheels can be used or are you staying with the stock track width?

[1972fritz]

You guys tell me what you think? Is it something you would be interested in? Could make and option.

[Mike_B]

The guys at SCR are doing this right now on my car, although it's not a tubular, bolt-in solution. I think with a proper jig and means to weld in a new tab to support the E30 diff it should be pretty straight forward. It will result in a wider track, but it will be easily accomodated by the flares going on the car.

Matt details a portion of the process in the thread below.

http://www.bmw2002faq.com/component/option,com_forum/Itemid,57/page,viewtopic/t,305235/highlight,/

[Lorin]

This is a very good idea. may suggest a few differences? I think it would make a lot more sense to use 6cyl E30 trailing arms as well otherwise you will have a diff capable of several hundred HP that would destroy the 02 stub axles, wheel bearings, etc. The E30 TAs have a better camber curve, are readily available, and have the same style of spring as 02. You get disc brakes too. Most people that would want this are going to putting some HP down so narrowing the track to the inside of the wheelwell with a typical offset wheel would be a plus. Are you thinking custom halfshafts? You could perhaps use spacers on each end to allow for a narrow axle width and stock width.

[Guest]

Are you planning on a "narrowed" design so wider tires/wheels or lower offset wheels can be used or are you staying with the stock track width?

Depending on what the "disc to disc" distance is(from where the wheel sits against the disc rotor), narrower would be good. You can't get it any narrower than stock since the tires will rub on the inner portion of the fender(trunk side, not fender lip area).

It might be a little much, but having two options would be good, one based of a custom tube frame and another just a modified E30 rear subframe since that might be cheaper, just move the trailing arm and subframe mounts in a little bit.

I'm planning on modifying the E30 rear end myself, depending on what the extra track width would be I may stick with just moving the subframe mounts. I've got turbo flares and 15x8 et15 wheels with 225/50 tires(changing to 225/45), as is they sit barely inside the turbo flares. 15x8et15 with 225's is the highest offset wheel you can get on the 2002 with out the tires rubbing on the struts and portions of the rear fenders. ET10 would be ideal, but no one makes any to my knowledge. ET0 is the most common.

The possible benefit to running the stock E30 setup with just the subframe mounts moved is being able to use 15x8 et25 wheels which are super common for the FWD guys, however you'd need 10mm spacers up front for that to clear.

If you need an e30 medium case diff you're probably making over 275hp and running 8" wide wheels. Turbo flares would be a minimum, and probably quite common. The buyer probably doesn't want to have different offset wheels up front(or thick spacers) so making the rear end similar spacing to the stock '02 rear end would be good. Any narrower than stock and you'll start to run into inner fender clearance issues.

I wouldn't worry about a driveshaft adapter since anyone doing this is almost certainly going to be running a 5spd and will need a shortened driveshaft already. If you're keeping the track width the same you'll probably need custom axles. I've got the measurements from end to end of 2002, e21, and, e30 complete halfshafts but I don't know the actual axle width(haven't taken any apart yet). You may be able to get away with e21 axles and e30 ends, but again, if you're making the power necessary for this rear end you're better off just going custom. E30 axles can handle a good amount of power(450-500 from what I've gathered off some forums) but they're too long(unless going with the stock E30 width which kinda negates the whole process).

[1972fritz]

I think I'm going to start with replacement subframes that use stock trailing arms at this point in time. Once I get the new shop up and ready I will have more time to start on grafting e30 parts into them. We will see though the jig is being made now and next week I should have a better update for you guys.

[Guest]

Don't go with stock subframes, it's a waste of time for all that fab work. At least go with E21 trailing arms since the '80+ have stronger stub axles and are only 5mm wider on each side. Plus they come with 250mm drums already and are boxed. Yeah, you'd need to weld on a spring perch, move the sway bar mount(on the subframe), and add a mount for the damper, but all that is trivial if you've already got a motor putting out 275+hp. If you used stock '02 trailing arms and an E30 medium case diff you'll still need custom axles and it would be a waste of money to buy custom axles for sub-par trailing arms which will need to be replaced.