I have a STOCK 2004, with 96k miles on the original motor. Still runs awesome but I'm starting to get a CE with p0420 code.

Which allegedly is the CAT is going bad. I also have a bit of fumes at idle sometimes.

The exhaust seems "normal" in that it's not plugged, I still have plenty of power, and it doesn't feel restricted. If it weren't for this code, and the CE light you wouldn't know anything's wrong.

So, folks say aftermarket $300 cats don't last, but since my car is bone stock, not even a cold air intake is that still an issue?

I also see that the note on some of these is that the cat doesn't fit the touring model. Which is what I believe I have, 2004 velocity red, 6-speed, heated seats and all that jazz. I guess I'm not sure why it wouldn't fit.

Anyone?

 

You should probably drop the cat and look inside it before you do or buy anything.

Sometimes when they go they will clog in various ways, or, it will just disintegrate and blow out the back and you'll never be the wiser except the code.

Check it yourself first.

 

As Dominarian says, pull it down and check it.

Also, you're asking very basic questions, which leads me to believe that you haven't read the new owners threads. Do that, so you can get a better understanding of the Renesis engine.

 

mdisher, be prepared for a flame or two (surprised i havent seen it yet tbh) , as RX8 Soldier said, it would benefit you to read some of the new owner forums. In short, the only cat worth having is a mazda OEM one for your vehicle. if its a cheapy from autozone or wherever else you decide you should get it, it WILL Melt. Rotarys exhaust heat is substantially hotter than your average corolla or civic and the cheap cats are not made to withstand the rotary's heat. For example, when i bought my 8, the cat was bad while it was at the car lot. i pointed it out, they replaced it with a cheapy from the nearest autoparts store and said it was what the car called for. less than 100 miles later it was fried. Dont waste your money on a cheap CAT. If you have the option, just gut your cat. Rotaries and cats just dont mesh well. If you have emissions requirements, and dont have somebody that will sticker your car without testing it , this may be an issue. In which case, you may be able to justify buying a cheap one for use only during the timeframe of emission testings. Clogged cats can cause a huge amount of headache, including destroying your engine. In short, you get what you pay for; if you must have a cat, dont get anything other than the roughly 1000 dollar mazda rotary OEM one, if you can get away with not having one, save yourself the trouble and just punch a hole in it. They really arnt worth it.

 

While it is true that cheap cats don't last on the RX-8, there are aftermarket options. HJS is reputed to make quality CATs that can stand up to track use when sized properly. It will cost you though ($550-750). BHR also offers a CAT with their mid pipe that they say is fine for normal street driving.

 

BHR was the only one that i was aware of that made something other than the OEM that would withstand our heat , but i do stand by my statement of no cat > any cat if possible.

 

Thanks fellas,

I did search the board(s) and didn't really find anything useful other than other folks flaming other folks asking questions. And most of the links to I like this cat or that cat pointed to places that no longer existed.

It also seemed to me that *most* other folks are tweaking their cars in one way or another adding to the problem (more air in = more air out, and probably hotter air).

My 04 is bone stock, with 97k original miles, original motor, no warranty swap.

I am 99% sure my cat is blown out. I have no performance issues, no noise issues, but what I do have at stop lights is crazy fumes which all adds up.

Only recently did I start getting the 420 errors but I have Scan Gauge so it's easy to clear. I'm not about to drop a grand on a Mazda OEM cat, that's just not gonna happen for a 12 year old car worth maybe $6k?

I did buy the ~250 aftermarket cat/mid pipe. But I don't think I'm going to install it. Since I mostly ride the spring/summer/fall with windows down because our AC sucks I'll probably be OK. I didn't drive my 8 much this winter.

I also have new plugs and wires to put in as soon as there's a nice day.

Thanks for the tips!

-=MD

 

Driving with a clogged cat is like running with a clogged *******. How long do you think you'll last?

Either replace it with an aftermarket (as mentioned), or search the part out threads. Many people sell theirs for cheap when they purchase aftermarket midpipes.

 

The fumes could be a simple exhaust leak. Drop the cat and actually inspect it before spending money...

 

You don't have to drop the cat to inspect it, you can test it properly using a laser thermometer. Google is your friend.

 

For the love of got please don't drive with a clogged cat. You are risking your engine every time you do that. Listen to 9k or rx8, i don't care how you check it, but if you don't , and next week you have your car in the part out thread to try and make some money back off your now blown car, you really only have yourself to blame.

 

This is pretty much all you need to know about cats and RX-8s.

Your options are new or used OEM (street), HJS (track), and BHR (street).