snowrydr01

Has anyone attempted to gut the stock Cat while leaving its shell on the car? I live in a state where Cats are required. I did this with my previous jeep and it passed visual exhaust checks time and time again. I was just wondering if this is a feasable option. With everyone upgrading to midpipes and high flow cats it may be an economical option to buy someones used Cat, gut it, and throw it on.

Red Devil

The benefit won't be as great as a straight pipe as the diameter isn't as large, but I'm sure you'd pick up some hp. That said, however, you will almost undoubtedly get a CEL.

snowrydr01

Im necessarily looking for any major HP gains, just a slightly throatier sound for when i get an exhaust so i dont sound like a cracked out mesquito. Just a question, why would i undoubtedly get a CEL with a cleared stock cat while some aftermarket midpipes can run without recieving the CEL?

Red Devil

That would by why I said, "almost". Seems some of our 8's are perfectly fine without the cat and get no CEL. While others have had lingering problems with this and used 02 foolers, etc... Replacing the OEM cat is expensive. If you gut it and start having CEL issues is it worth the hassles?

G8rboy

You will most likely get a CEL if you gut it. If you select the right exhaust (based on your sound requirements), I think you'll be happy without gutting your cat. My Greddy SP2 has a great, fairly deep, kinda exotic sound without the usual rotary screaming chainsaw sound. I plan on eventually getting an RP supercat for the HP increase, but am worried a bit that it will be perhaps too loud when combined with the Greddy exhaust.

P.S.- I also gutted my old Miata's stock cat and ran with that at the track/autocross, but ended up replacing it with a high flow cat and didn't feel like there was much of a performance drop off. It also cut down on the fumes, which you'll really, really notice with a midpipe or gutted cat on the RX8.

arghx7

uh yeah dude when you gut the cats it has a very distinct smell

snowrydr01

I have had gutted cats before, i kinda like that unburnt fuel smell. As far as Red Devils comment about it being a hassle to replace with a new one if i gut I understand. Thats why the plan was to get one used off the forum for cheaper then i could get a midpipe for anyway. This way it would look legit for non-emission inspection but serve pretty much the same purpose and be cheaper. With the exception of the smaller diameter piping it seems like a win win all around to me.

Pololo_RX8

The way I see it is that OEM cats are even more expensive than a midpipe.

Heck new ones at the dealer are $1200.00 and I am sure you'll start seeing more and more threads with OEM cats for sale for no less than $300

I have an extra OEM cat and no way I'll let it go for less than $300...

My 2 cents,
Carlos

snowrydr01

theres 2 posts right now for under 150 + shipping

Pololo_RX8

Yes... right now... and there is only one. Give it a few more months. Indeed if I posted mine for $200 I am sure I'll sell within 1 day.

I am not in a hurry... I'll sell it when the time is right.

NO CAT = CEL (just be aware of that)

Carlos
ps. Get a Borla exhaust and a nice intake. Don't destroy your cat...

snowrydr01

i would never destroy MY cat. The point of this post was to talk about the option of gutting one of the cheap used ones on the for sale section for cheaper then you could buy a midpipe with resonator.

Nemesis8

iTrader: (3)

LOL

https://www.rx8club.com/series-i-aftermarket-performance-modifications-23/higher-flowing-stock-cat-81366/#post1212236

mikeschaefer

can someone email me the smell of an 8 with a catless midpipe? lol


seriously though, anyone in hampton roads, va area without a cat... can i smell your car? please?!

TeamRX8

iTrader: (25)

if all you want is a throatier sound then you would be better off cutting out the resonator after the cat rather than being an illegal polluter

urby1970

I gutted my CAT, being stupid, and the smell is bad. You WILL NOT get rid of the CEL. Plus you are going to get dinged if you have warrenty work done. I am buying a high flow CAT to replace the OEM one I gutted. Don't do it, It's not worth it, and the HP gain is minimal, and the sound is no different. Give your stock exhaust and CAT some time to tune itself. I have 23K miles and I have noticed that the sound of my car gets better every day.

boostedrx8

very bad for the ozone for little hps. that's what i hear