Thank you sir... i'm gonna give this a try

 

Short update. Unfortunately no pictures on this one. Which I guess is a good thing. Means I have no pictures of broken parts to post. So I have put 4070 miles on it so far with no issues other than the ones already mentioned. Main reason I was giving an update was I went to the drag strip this weekend. Made eight passes. Got wheel hop on two of them. My mount seems to have survived drag launches, though since I'm n/a and still on the stock ECU that may not be a very impressive feat. Best was a 10.32 in the 1/8( it's an eighth mile track). So pretty slow compared to my wife's uncle's 2019 Mustang GT that made a 8.15 sec pass. Crawled under the car and from what I can see nothing looks cracked or broken. The sway bar looks like it's touching on one side and I don't remember if it was like that before. Nothing seems different while driving. Eventually I will take it out and look it over. Then I'll really be able to tell how it's holding up. I'm feeling pretty good that it will hold up until I go turbo and start making some power.

 

Well a short update. I went to pass a car the other day but there was a car coming so I had to wait. Was a small section of passing zone left so I dropped down to second since I was only going about 40mph. Upon the upshift to third I heard two loud pops. At first, I thought it was exhaust but it sounded more like something broke. I also started having some random clunking sometimes during initial acceleration. I have since discovered that the carrier that the rear end bolts to is cracked. It is almost broken completely in to from what I can tell. The only portion still intact looks to be the additional metal I added to the front for extra bracing. I think it's been cracked awhile because there is rust in the start of the crack. I think that hard 2-3 shift opened it up enough that it's now unstable. Pictures to come once I get it out of the car. Also it lasted 2 years and 12,000 miles.

 

Mine is still holding fine, but last trackday when drifting with toyo R888 it felt like rx8 superLSD is slipping and diff becomes to act as open diff.......with street tires (less traction) its not happening.......maybe i will need to put in FD torsen....

 

I had picked up an FD Torsen awhile back. I found one for $275 + $25 shipping for $300 total so I snatched it up to save for later. I also picked up another Rx-8 diff from a A/T for $80 + $69 shipping to get the 4.3 gears from in case I want to go back to them instead of the 4.44 after I go turbo.

 

I finally got the diff out. Here are some pictures


Looking at the below picture I think my clunking was the sway bar hitting the mount.


The piece I added to the front for extra bracing is all that's holding that side together.

It broke in what I always thought was the weakest point. The other side does have more material in that area and might have made the difference. The way the diff is shaped on the side that cracked made it hard to do the same on that side. For now I am going to weld the crack back together and come up with a way to add more material to that side. I have some ideas in my head. I will eventually build another one. A version 2 so to speak with improvements incorporated from what I've learned from this one and how well the bracing I will add now works.
On the bright side it looks like my welds held up for the most part. There is one in the last picture that looks like penetration might could have been deeper. That's all for now. More pictures later when it's repaired.

 

diggin this back up for fun but I did find out that my FC axle fits right into the miata/rx8 hub. This may be of importance on another project I'm working on

 

Thaks for digging this up. I am such a slacker. I repaired this crack and added extra bracing that utilizes the top two bolts of the diff cover in an attempt to replace all that metal that had to be removed to clear the diff itself and strengthen things up, took pictures and then never posted them as an update to this. I have been driving around on it for over a year now. Who knows when I would have realized I never updated this if you hadn't of posted. I'll try to find and post those pictures tonight or tomorrow.