Donor for Cheap/Light IRS assembly?

I figured if anyone would know the answer for this, it'd be here.

I'm looking for a RWD car with independent suspension that I can lop off the subframe and shoehorn it under the back of a LBC.

Miata obviously comes to mind but I was thinking there has to be something else out there.

whats an LBC? hyundai santa fe has an IRS that looks adaptable(if the car recieving it is light enough)

Little British Car

The S2000 probably fits the bill. I'd start off by identifying what the track needs to be, as you'll find that most modern cars are a lot wider than your typical LBC.

I am doing the same for my fiat. Lopped off the mounts and trunk from an E30 for mine

In reply to CLynn85:

Here is a link for a Datsun Diff in a Spitfire if that is your car:

http://pages.prodigy.net/mikeross/00019.htm

Todd

Lord knows there are enough kids totaling their "drift" cars, so if I were you I would look at the 240sx and 300zx rear ends. Seems to me that they are tough enough, seen quite a few around here holding down 400+ whp. There are two 240s near me that are being completely parted out, I know you could get the rear subframes from them.

Local fellow put a rotary engine in a bugeye and adapted the RX-7 rear into it. Never really crawled under it to check it out as he was a bit hard to catch.

Bruce

early or late Rx7? the first gens used a solid axle

Well the obvious is Miata since it's lighter and cheaper than the S2000.

I too would be interested to see if there is something lighter and smaller - cheaper would be nice.

Isn't the 2nd and 3rd gen RX7 very similar to the Miata?

Some early Datsun/nissans had some okay IRS setups. Look at 510, 200sx, 240/260/280/300zx.

Depending on the room available, a good 4-link with Watts or a Mumford link can be just as effective. Heck a De Dion might be easier to do than a full IRS swap.

Not sure if it fits the bill, but '99-'04 Cobra IRS units can be had for CHEEEEEAP and are designed to be bolted in in place of a straight axle. Diff is a Ford 8.8", so you can get any gear ratio you want and any LSD ever made.

Later is stronger, though the '99 units should still be overkill unless you're doing an LSx swap. Because of the strength, earlier is cheaper, I've seen '99 units going on the Mustang boards for $100, and usually no more than $350.

EDIT: These all have a clutch-type limited slip stock, and I believe are all 3.27s (some may have 3.55s).

The rears on any BMW will switch over nicely. Many have limited slip. They come attached to a ready to transfer subframe that houses just about every piece. Most have rear discs. I've toyed with the idea of putting one under my next TR8 project. Current project got a cut down 8.8 out of an Explorer, and that turned out to be a lot of work for the weight I have to contend with now.

fiat22turbo wrote: Isn't the 2nd and 3rd gen RX7 very similar to the Miata? Some early Datsun/nissans had some okay IRS setups. Look at 510, 200sx, 240/260/280/300zx. Depending on the room available, a good 4-link with Watts or a Mumford link can be just as effective. Heck a De Dion might be easier to do than a full IRS swap.

Negative. Miata uses A-arm, FC trailing.

The answer to this question is, as always, Miata.

tr8todd wrote: The rears on any BMW will switch over nicely. Many have limited slip. They come attached to a ready to transfer subframe that houses just about every piece. Most have rear discs.

That was why I chose the semi-trailing arm set up of the BMW over the A-arms of the Miata. lightweight, compact, simple, and easy to bolt up/weld in the supports.

As I own a Ti.. I am also familier with that set up's handing quirks

Sean Korb's SUPRANG used the IRS from an '82 Toyota Supra

Some good ideas. The car is a spridget with cancer all over, which I tried to sell out but since they're apparently worthless in this condition, it's going to be a challenge car. Being a spridget, unless I figure out a relatively simple way to push the front track width out, then that's going to be an issue for whatever rear I can find.

How about an older subaru? Any redeeming qualities there? I figure they should be close to narrow enough and definitely cheap. Never seen an rx7 rear other than the first gen straight axles, might have to look into those.

What production cars use DeDion rears that were sold here in any reasonable number???

My old Subaru wagon (1987 or so) may have had a DeDion, actually. I never spent a lot of time under there looking at the suspension, but I remember a big beam axle of sorts as well as IRS-style halfshafts.

The fact that you're trying to put this under a Spridget is going to be a big problem. You want the narrowest donor you can find. My MGB with Miata suspension is going to be about 4" wider than stock. I say you stuff the Miata front subframe under there as well.

mad_machine wrote: I am doing the same for my fiat. Lopped off the mounts and trunk from an E30 for mine

Would love to see a separate topic on this - with pics!!!

Come spring you will. repainting my saab right now and then the BMW goes into the garage for some welding, painting, and general work. Once it comes out, the cover comes off of the fiat and I can start work on her again

XR4Ti, tbird/cougar/mark(heavy and big), 190e, 2002s

Ooo, a 2002 might be narrow enough.

I know a guy in Charlottesville, VA that usually has a number of 3rd gen RX-7 parts cars available. I can put you in touch with him if you're interested. For your consideration, 3rd gens have double wishbone in the rear and use pillow balls (not rubber bushings), aluminum arms, etc. Don't know about the rears, but in the front, at 2 inches of roll the suspension picks up 3 degrees of dynamic negative camber. Race car geometry right there ;P Might be too wide your your application though.

Why not keep it in the family and use a Spitfire rear?

I think I'd go with a Miata rear, realizing it's going to be VERY wide for the Midget. Honestly, pretty much nothing other than a Spitfire is as narrow as a Spridget.

For the front, I'd either take Keith's suggestion and put the Miata gear up there, or grab a complete MGB from x-member and graft it in.

The B front will be about 4" narrower. I don't think I still have a spare MG front subframe around here, but I can look if that's the way you want to go.