ryno255

The exhaust on my 03 evo smells like rotten eggs, i think its the cat. so what I'm thinking about doing is hollowing out the cat, but will this trip the o2 sensor and throw the CEL on. if so is there a fix for that like an o2 sim or something like that?

NocturnalEVO

iTrader: (39)

yea there's 2 solutions available.

the electronic o2 sim, i think PERRIN makes it?

OR you could go with a o2 sensor spacer. Search around, u'll find the answer.

Jakeg97

iTrader: (56)

never heard of the mechanical o2 fix called ^^. but whatever works
https://www.evolutionm.net/forums/sh...d.php?t=114931

NocturnalEVO

iTrader: (39)

lol well it does space it out.. the name slipped from my mind and that's the closest I cud come up with

ryno255

thanks guys, i did find that perrin fix too, but i do ike the idea of spending 8 bucks and making my own. so i guess the hollowing begins. sure will be nice to eliminate that rotten egg smell its not to popular with the ladies

Doogie Howser

iTrader: (2)

When you go catless another odor emerges

NocturnalEVO

iTrader: (39)

this is truee..

MR 8U

Hmmm...I guess it's just me, but I don't smell anything different after replacing my hfc w/a testpipe I guess it's a good thing

ryno255

well the deed is done, and come to find out the previous owner must have installed a non fouler cuz there was one already there and so far no CEL..... You know the only odor i notice it smells like fuel a bit more, I'll take that over rotten eggs any day

MTMS4

Well, if that's the case your cat is probably shot.

If you hollow it out you've got little chance of passing an emissions test (even if you eradicate the CEL light with an O2 fix), but if it's shot already that's a moot point.

Changing an OEM cat (to a test-pipe or HFC) is actually an offense in many/most States which comes with a BIG fine if you're caught and reported.

Nextcar

Try this on your Cat
Cat dance
cat removal

tarmacevoviii

I've done the mechanical o2 sim on my past car (s2000) works like a charm, doesn't even cost $8....

UT_Evo

iTrader: (5)

Yes, hollowing out your cat, or even just making a testpipe look like a cat is illegal in many states... But chances are you WILL pass emissions, just pray they don't find out that it's hollow. (I passed emissions catless, but they have to be able to visually see a cat under the car and, well, obviously they couldn't... so I went back with a HFC on the next day, they checked me off in like 30 seconds, then I left and switched back)

05-EVO-GSR

iTrader: (16)

To answer the original question, yes it is a good idea. Enjoy the extra 10 H.P.