[Dan0myte]

RX& TII Parts

What's the general concensus on transplanting late model rear ends into the Opel?

I recently came upon a head-on collision 1987 Mazda RX7 Turbo in a junkyard that I can get the entire IRS from. It comes with a 4.1:1 Torsen LSD differential, nice thick CV shafts and a beautiful suspension linkage. I took at tape measure to it, it measures 60" from outside tire edge to outside tire edge. I came home and did the same measurement on the Opel, it also measured 60" exactly. The TII rear end has been tried and tested by the RX7 crowd safe up to 500hp.

What do you think? Can it be done?

 

[N61WP]

I'm not trying to sound like a smart a--, but you can do most anything with enough time and MONEY! I recently saw a complete 2nd gen RX7 rear suspesion on the floor at a buddy's shop. The whole subframe, not just the chunk and axles. It is a nice looking setup, but on the heavy side. It also has a rear steer feature built into it that most of the racers don't like. The Mazda aftermarket places sell a bushing kit to get rid of that for performance driving. I'd guess that in the Opel, some type of sub frame would have to be fabricated, and only some parts of the Mazda assembly would be used. Granny's Speedshop sells V8 kits for the RX7 and say the rear end handles the power with no problem. Keep us informed.
James

 

[kwilford]

I moved this thread to the "Engine Swap Forum", since differential swaps are almost always related to an engine swap.

As for fitment, I believe this exact idea was discussed a while back, and should be on this heading. The biggest issue (aside from the obvious extensive modifcation to actually ATTACH a separate rear assembly) is the width. The 2nd Gen RX-7 seemed to be the closest fit, but it was still quite a bit wider. Which is probably a good thing for handling, but will require fender flares or blisters. Which are also a good thing, if you like the look.

Good luck!

 

[kwilford]

A quick search under "IRS" found the thread, although I had earlier moved it to the "Suspension & Steering " heading. But with one flick of my mighty Moderator wand, and voila, it's where I said it should be.

Or more accurately, at:

http://opelgt.com/forums/showthread.php?s=&threadid=749

 

[Dan0myte]

Thanks Keith.

Looks like it could be done, but would require a metal fabricator to basically rebuild the entire back half of the car Bah. I thought you might be able to just have some new mounts welded in and some shock tower modifications.

Guess I'll have to keep looking for some solid axle options.

 

[Dan0myte]

Interesting info from a Cobra kit car company:

"Some Cobra kits use independent rear suspensions. The importance of an IRS is big if your car weighs in at 2600 lbs. or more and you spend hours at your local track. The reason we went with the Mustang rear is primarily a cost advantage but when we worked out the final vehicle weight to be an amazing 2,000 lbs., it really didn’t matter much. We added custom anti-squat geometry, similar to those used by the Mustang 5.0 race crowd and engineered all mounts to be in double shear, with 3/16" A36 plate steel. With these minor modifications the car handles great and this one move can save you up to $4,000 right off the bat."

Sounds like they've tried IRS and Solid axle on their 2000 lb test car, and the IRS didn't many any difference in handling.