FC subframe into FB thread

[Whizbang]

(i might change / update pictures with better ones as I go)

seems to me that we dont have any official thread on this. I have converted five cars to FC subframes now and worked out a few kinks along the way. Also, I have some "options" to consider when doing your own that can lead down some different paths.

But first, let's discuss a little history.

The 2nd generation RX-7 had much effort placed in the engineering process. To protect the image of the new chassis, Mazda utilized the FB chassis for testing of the various concepts of the FC suspension. I read about this in a hardback book from the era plainly called "Rx-7" written right as the car had come out. Pictures showed the test mules, and suspension configurations. So this got me thinking that it could be similiar but I never bothered to continue much with it.

Then Pete, rotary fellow in Cleveland, started messing with actually doing the swap. He confirmed that the front studs of the FB subframe can be used to located the FC subframe! Now, this does cause an increase in the wheelbase and therefore, gains in caster and issues with clearance to the fender. This can be accomodated however as having something to locate the subframe minimizes your chances of being "off" during install. And also, more caster and wheel base is a good thing!

So what do you get?
FC brakes, suspension (including sway bars and struts), steering, subframe while removing the clunky steering box and linksages and rather hefty old FB suspension. Moreover, you can get rid of the crap lug pattern, the out of date strut design and modern brakes. Win-win.

So what goes into doing the swap?

There are a few ways, but here is how I do it. We can discuss alternatives, results, etc afterward.

[Whizbang]

(i might change / update pictures with better ones as I go)

seems to me that we dont have any official thread on this. I have converted five cars to FC subframes now and worked out a few kinks along the way. Also, I have some "options" to consider when doing your own that can lead down some different paths.

But first, let's discuss a little history.

The 2nd generation RX-7 had much effort placed in the engineering process. To protect the image of the new chassis, Mazda utilized the FB chassis for testing of the various concepts of the FC suspension. I read about this in a hardback book from the era plainly called "Rx-7" written right as the car had come out. Pictures showed the test mules, and suspension configurations. So this got me thinking that it could be similiar but I never bothered to continue much with it.

Then Pete, rotary fellow in Cleveland, started messing with actually doing the swap. He confirmed that the front studs of the FB subframe can be used to located the FC subframe! Now, this does cause an increase in the wheelbase and therefore, gains in caster and issues with clearance to the fender. This can be accomodated however as having something to locate the subframe minimizes your chances of being "off" during install. And also, more caster and wheel base is a good thing!

So what do you get?
FC brakes, suspension (including sway bars and struts), steering, subframe while removing the clunky steering box and linksages and rather hefty old FB suspension. Moreover, you can get rid of the crap lug pattern, the out of date strut design and modern brakes. Win-win.

So what goes into doing the swap?

There are a few ways, but here is how I do it. We can discuss alternatives, results, etc afterward.