Hey so I'm new to RX8 club and new to owning an RX8.
To start off I own a 2006 RX8 GT with about 130k on the first engine. (Which is running great btw) I had no problems with the car what so ever and then all of a sudden I blew my cat and cracked the muffler. So my mechanic did a weld fix on my muffler and gutted my cat. Today I was driving and all of a sudden lost all power and my car is struggling to stay in idle. It feels like something is congested and when I give it gas my car vibrates and sounds like crap. I can't drive it at all because I have no power. Even if i push it to the floor I get no where. My rpms climb normally but I get no response. I was thinking it could be coils or plugs.. But my mechanic thinks it's my muffler (clogged with **** from my cat taking a sh*t) so all in all, I need a new muffler and cat. Should I just leave the mid pipe there and get a cat back exhaust to solve 2 problems in one? What brand should I look at? Mazda wants 2000$ for a new cat and 500$ for a stock muffler. I have like 700$ tops so spend. I'm stuck and don't know what to do.. I'm not looking to race it or take it to the track. So I don't need a high performance exhaust. I don't really care I just want something reliable.

Please help!
Thanks, Caleb

 

If your rpm climbs but the car doesn't go faster, that's your clutch. Certainly have the muffler checked, but if you gutted the cat, there is nothing more to clog.

But! The likely cause of your cat blowing out is bad ignition coils and you'll want to replace them if they haven't been replaced. Same for spark plugs and wires.

Don't even think about spending money on a cat until the car runs well without it, you'll just fry your new cat. Maybe a new mechanic also, his assessment is wrong.

 

Even if it falls below 1000 rpms and struggles to stay on? when I'm in neutral I gas it and it feels like there's congestion. My car vibrates from what feels to be the exhaust. Thanks for the reply!

 

Well you said your rpms climb without a response. That's automatically clutch. The rest points to complete ignition failure. Get that fixed before anything else.

 

Sorry, my rpms climb but not easily. It's rough and my car gets the shakes. When I put it into gear and try to go I can't acceeed 5kmh. Sorry for the confusion. I'll get my mechanic to check the clutch. He's getting back to me tomorrow. You know how much for a new clutch? I'm guessing like 1000$

 

It sounds to me like ignition is the place to start. One or more bad coils likely killed your cat. It sounds like you recently lost another coil. You should inspect your ignition health every 10K miles and replace the coils, wires, and plugs every 20 to 30K miles depending on which coils you buy.

I didn't want to keep replacing coils and wires in perpetuity, so I bought the BHR ignition kit and just replace my plugs yearly.

Ignition health is extremely important. Bad coils kill the cat. A bad cat kills the engine.

Read this carefully if you haven't already.

 

Ya that's what I was thinking.. So I'll fix the problem. Should I drive with the gutted cat or should I replace that too? Also like I said my muffler cracked too and they just did a quick weld fix to get me by. Should I get a new cat and a new muffler or could I get a cat back exhaust and just kill 2 birds with 1 stone? I don't know much about them..

Thanks

 

Ignition first for sure. You can make decisions about the exhaust after that. You don't NEED a cat or muffler for the car to run. You don't even new a new muffler at all, just shake out whatever is or isn't loose in there and reweld the weld if it's not holding.

Maybe I jumped the gun with the clutch, your description is a bit confusing. You can diagnose that after the ignition.

 

Sorry about the confusion im unsure how to explain it! Thanks for the help guys I'll let you know what I find out tomorrow

 

Report back tomorrow, but make sure you read the new and potential owners thread that I believe Steve Dallas posted for you (edit: yup, thats the one). Read it until your head hurts, as it sounds like you have very little understanding of even basic maintenance.
Understanding the basics will assist you later down the road. With ANY vehicle...

 

So my mechanic just called. I blew 2 coils so he's going to replace them. Nothing to do with my exhaust like he said might be the problem. He says I need a tune up and all should be good to go.

On another note. I need to look at getting a new muffler since mine has a temporary weld fix. It won't last forever. Should I put a mid pipe where my cat was and get a cat back exhaust so I replace the cat and muffler all in one shot? I just got a e-test and am good for 2 years.. Just need some sense of direction. What's a brand that you guys recommend?

 

Did you bother to read the thread that we recommended?

 

Yes I did actually I book marked it so I can go back and read it anytime. I read the entire thing

 

Then read post #2: how to best search the forum. You need to make your own decision regarding what's best for your car.

 

Well thanks for the help anyways! I'll update with what I'm going to do.

 

If you live in a state with emissions testing you will need the catalytic converter, but the car actually runs better without it. I run a mid pipe and when the car is due for inspection I put the CAT back on, pass test and then remove it. As far as exhaust you need to search that one. There are lots and each has its own set of attributes.

 

Let's try to break this down:
- the muffler is a piece of metal, it has no moving parts, nothing to wear out. There is no reason that weld shouldn't hold for a long time. It makes a difference where the weld is, if it's where a pipe connects to the can, then it could fatigue and break again. The downright cheapest solution is to have it welded properly. The next cheapest is to get a used stock muffler. In fact if you come to Montreal, I can sell you mine.

- you need a cat to pass emissions testing and the only brand that will work reliable is Mazda's original. They're SUUUUPER expensive, but look for a used one (junkyard is a good place to start).
An aftermarket cat would be fine on any other car, but the rotary will cook most aftermarket cats in short order. You can try to risk it of course.

 

Yes that's exactly where the weld is. Right where the pipe hits the can and its broke for the second time now in the same spot so I'm not expecting it to last a long time. Would it make any difference if I got a cat back exhaust? As a second option if I can't find a used stock one? Or should I look into getting a new muffler and a new cat!

Thanks for all the help

 

You can buy whatever catback you want. You won't get any power gains from it, but you can choose based on sound and appearance.

The only cats that will stand up to our engine for any length of time are the OEM one, which you can buy used, or a couple of weld-in models from HJS. If you go weld-in, a muffler shop can probably cut your old cat out of your OEM midpipe and weld the new one in. Or, you can buy whichever midpipe you like and have the cat welded into it. The BHR midpipe is generally accepted to be the best option.

 

Im surprised nobody else mentioned this, but to my understanding you lost two coils and are going to replace those two? i dont know if you have recently replaced coils , but in my opinion (and most others) if your replacing coils, dont half *** it. Do all 4. there is no point in 2 failing and causing issues, and expecting the other 2 to last another extended amount of time without causing your next cat to fail or cause other ignition related problems. BHR has a great ignition kit, and if you cant afford that, autozone has lifetime warrenty, so get 4 coils and essentially get coils for life.


Edit: just realised this thread is a month old.... sorry for the thread revival guys. Bored at work and have just been skimming the new member threads to offer 2 cents