Broken subframe diff mount?!?!
 

Some how I managed to break the subframe differential mount, the mount itself, not that huge chunk of rubber, today...still a little perplexed, but it ripped it to shreds. anyone else dones this?? I am assuming because the 4th gear pull against that single turbo FD I raced last night finally did it in..and I have 220k on the chassis

Are you talking about the front differential mount that attaches to the subframe? Those are the ones that will always break if you don't have stiffer rear diff bushings or a pinion snubber...

The front mount is rubber bonded to a metal plate. If you're talking about the metal tab where it mounts on the subframe, then you're not the first person to break that either. This writeup should be helpful when you go to replace it: https://www.rx7club.com/2nd-generation-specific-1986-1992-17/pinion-snubber-diff-mount-replacement-convertible-876959/

Ok, not the actual diff mount itself. I have replaced that before.. I am referring to the metal bracket that is welded on the subframe, where the diff mount fastens to.

Yep, Something like this https://www.rx7club.com/attachment.p...1&d=1275357628

Had 3/8" PL welded to it for $20 and then notched it.https://www.rx7club.com/attachment.p...1&d=1275357718

https://www.rx7club.com/attachment.p...1&d=1275358053

Only flaw is that I dont have the little hook on there for the double plate washer thing, but it hasn't given me any trouble yet.

I think it's hard shifting that usually breaks it. Good luck!

OK! yeah, I am normally pretty easy on it..when it broke it, I started building boost and it began spinning just a hair on a wet road, the pavement went dry, I think it caught and broke it, I am going to try one more stock one since I can get a subframe for $60 and I don't have to wait until the weekend, but I like what you did, if it breaks again I'll probably go that route.

Use a pinion snubber and possibly solid diff bushings on the rear...

i broke a few of those when i had my turbo II,i had to put another diff crossmember in with a pinion snubber and a better diff mount.

I would save yourself the trouble and weld it before you put on a new'er rear subframe. I also installed the Competition Mount from Mazdatrix and a snubber, but I still need to preload the snubber.

Made a new bracket out of 3/16's plate for mine, holding up strong still :)

Good Job Macz, Yea, I think the PL I had welded on was 3/16 also, not 3/8...

Been there, done that. I didn't use 3/8" though, I just laminated some 1/8" onto the existing material. You can see it in this thread.

Probably a good idea to do this any time the subframe is removed from the car for whatever reason.