Electro, if that is an OEM cat or one of most midpipes, then that nut is supposed to be welded on. Otherwise, just fit a box wrench on that end and use the deepwell socket on the other end. Start on the side with the spring.

And you don't have to remove the stud entirely. Once you have the front 3 disconnected, pop off the rubber hanger, and then drop the pip down and pull it forward to extract the studs from the catback.


SNTP, they might be 14mm if all OEM. Mine are a mix now, but I've replaced hardware so many times I kinda forget what it was originally

 

I think you're right RIWWP. I finally got a socket on that nut and pulled as hard as I could after liquid wrenching it. It won't budge. The reason I tried was that the other nut on the adjacent stud turned fine. Maybe it SHOULD have been welded on too but wasn't. I took a break but I'm going to go back out and try a deepsocket on the other end.

 

THat's what I thought . I keep reading "17mm" even in the Racing Beat MP install thread:

https://www.rx8club.com/do-yourself-...nstall-194450/

But my rear springed nuts look exactly like that and I'm sure they're 14mm.


Friend didn't deliver the impact today. Going to try the torch.

 

Okay so I figured out that a 13mm deep socket works on the reverse side of that bolt (the one exposed by removing the spring). In the process I broke the 3/8-1/4" adapter. Pulled out a 1/4" socket wrench and while attempting to turn the bolt I broke the actual socket wrench (it has not torque anymore). I'm at a loss on this at this point. I've never seen a bolt/nut so stubborn.

 

Not exactly on topic now, but I am so glad I have a frame lift!

 

If the nut and the spring are off, stop trying to remove anything else! Seriously, leave it there. Remove the 3 front bolts, remove the rubber exhaust hanger, and you can slide it out. Both my cat and my midpipe have the 2 studs sticking out of the end. Simple matter to just feed them in or out as needed during installation and removal...

 

I'm telling you, get the smallest power tool you have or borrow one from someone, and put an extension on it and with the right angle you should be able to remove it. After about 3 tries of trying to remove my studs by hand and spraying WD 40 on it and letting it sit there, I knew I wasn't going to be able to remove it.

 

or just leave the studs on there? Not required to remove, not required to transfer to a new pipe, PITA to remove, PITA to re-install, handy for holding up the rear of the cat/midpipe while you get the front bolts in place...

 

Okay maybe I should have explained a little better. I am not actually replacing anything today although I will be soon. I am trying to get ONE END Of the midpipe detached so I can shake the debris from my shitty and possibly dead Cat out of there so it will stop rattling. If I could get that last bolt off I could just drop the midpipe down at an angle and spill the debris out. Conversely, if I could get the midpipe detached at the muffler I could do it as well. Unfortunately that bolt is giving me hell and where the mid meets the muff I can't turn it enough to get that notch lined up to pu ll it off. It's seized on there pretty bad I think.

 

Ok, that is making a bit more sense.

At this point I'd still vote for removing it entirely from both ends, rather than continuing to break tools

Or remove all 5 rubber hangers for the catback/muffler and slide that off the end of the stud. Catback has no bolted connections, just those rubber hangers.

 

op buy better tools. where are you located? nvr mind. i just saw your location. maby you could get a local to help

 

I'm sorry, let me clarify, when I said studs I mean the nuts! Lol... Sorry about that, I had a hard time removing the nuts with hand tools.

 

The nuts connecting my cat to the muffler were stuck on there pretty bad, with the impact wrench I was able to remove them. Make your life easier... I saved myself a lot of time doing that.

 

Yeah, if they are rusted it can be a complete pain.

Here is a pic of the studs (courtesy of Easy_1)


The right side threads into the welded nut on the cat, and usually won't come out once it's in there, unless the nut proves to have a stronger grip. The nut on the left side is toward the rear of the car, and the spring keeps ALOT of tension on the nut until the spring is completely relaxed, which is nearly the entire distance of the threading. This whole assembly rusts badly.

 

Lol my whole stud came off, and the nut stayed on when I removed mine, that's how bad it was! There was no way it was coming off by hand OP probably has the same issue, rusted/seized nut.

 

THANK YOU THANK YOU THANK YOU. I'm sorry I was not understanding what you were saying. I didn't even need to worry about that stupid stud this entire time, it just slides right through. Once I realized that I remove the catalytic converter bolts and pull the whole thing out quite easily. Wish I would have understood this much much sooner.

Once disconnected from the midpipe I tilted the pipe down and this is attached is what fell out..... Last trip to mazda gave the engine a clean bill of health so I hope this is fragments of the cat that burned up due to 75000 miles and not some other engine problem.

 

Holy crap man... I would say get a compression test just to be safe, that is pretty scary.

 

I did get a compression test about a year ago. I don't drive the car that often but when I do I always make sure to let it warm up and I always red line it. I don't believe I began hearing the rattle in there until the one time I bottom out pretty hard going into a car wash. The is a noticeable dent on the cat itself. Is it possible that bottoming out while hot cracked something in there ?

 

Unless you had a full clog with massive power loss, that shouldn't have caused any engine problems. A cat failure that just removes the elements and makes it flow better isn't a problem. Most cat failures are clogs though, which CAN cause problems. And those problems might not show up in a compression test for quite a while. My first engine was damaged from a clogged cat, but it took 40,000 miles for it to finally fail a compression test.

 

The car drives great still so i don't know if compression has been affected. At this point though I don't think I'll be putting the cat back on. I'm probably going to go ahead and order a new one. I'm taking a break before I go back out and thoroughly inspect it.

 

If you really want to run with a cat, you aren't going to want to buy a new one from the dealer. $1,300 or $2,600 (different people get different quotes). There are a couple other cats from aftermarket companies that can be sufficient. See the 2nd thread in my signature, the section on catalytic converters. It's got to be a cat that hold up under the heat of our exhaust, and it's a key point that more generic cats aren't designed for.

 

how was looking at a magnaflow Catalytic Converter do you know anything about those? are they good? I can pick 1 up for about 250

 

If they are designed for street-use piston engines then they simply will not survive in our exhaust stream, as we have temps of 1,500-2,000F, vs a normal piston engine exhaust of more like 700-900F. Cats designed for high flow high temp race conditions can work, like those I referenced in the cat section of the modding thread. Some of them can get cheaper than OEM, though all of them will require an exhaust shop to cut the OEM cat out and weld the new cat in, which brings the price back up some.

 

FINALLY GOT MY FACTORY MIDPIPE OUT! It wasn't without a struggle though.

I first used my propane torch on the front flange bolts. With my 12" rachet and a WHOLE lot of raging and cursing, I broke the nuts free. Even though they were free, it was still extremely tight. Hence the reason I stripped one of the nuts closest to the trans. Took the Sawzall to that.

Took the torch to the rear springed nuts also. One of them was extremely tight even after I broke it free. I ended up snapping the damn bolt, which is a win. Both rear bolts were bent from all the torquing.

All in all, I found out I have super human strength today when I rage with a 12" ratchet. I never thought it would be such a tough job to get a factory midpipe out. I guess not everyone is lucky enough to have the right tools and a lift... Or just lack the strength of Thor (which was probably the damn guy that installed my factory midpipe).

Here's a pic of the snapped rear bolt.

 

Yup, pretty much. Glad you got it, and you will never need that pain again. But you can see why I recommend paying $20 to a corner shop to break them free