rear subframe questions

[cook11]

Good day,

I own a 1982 RX7 and the inner wheel wells are quite rotted along with the portion near where the trailing arms are connected to the body. My question is this:

Has anyone fabricated or know of anyone that has fabricated a rear subframe for the Series 1 to mount the suspension?

Would I be better off fabricating a complete box frame for the car?

Thanks,
Jon

[agent fabricateur]

Hi Jon, my car is in a similar condition. I think that building a subframe may be an idea if you plan on completely redesigning the rear suspension for improved geometry but keep in mind you still have to tie that in to the unibody, which has no provisions for this. That's going to mean a lot of welding and fabrication, as well as some engineering if you want your car to behave when you're done, or at least not grenade u joints and differentials.

In light of that, repairing what's there with a little fresh sheet metal seems by far the easiest and most sensible solution. You'll more or less have to do that to mount a sub frame anyway.

Also there are a few people on rx7club.com who have reworked their rear suspension in order to reduce the binding inherent with the four link. They retained the lower links more or less, opting to address the upper links as the way to improve the geometry. Lots of cutting and welding involved.

I'm still musing on rear suspension for my car, initially I had planned to run a traditional parallel 4 link with the lower links mounted to a DOM tube which would run below my cage's main hoop and tie into it, and the upper links also mounted to a tube tied into the cage. This would involve cutting that entire section of the unibody out and rebuilding it from scratch.

Connor

[TOOL]

If you're going to the trouble, what about installing the FC rear subframe with IRS?

You'll get a 8 inch Torsen LSD and bigger brakes too.

Then FC front subframe swap for matching brakes and hubs etc.