Xtnct00WS6

iTrader: (8)

What is everyone's thoughts about gutting cats?

I was thinking of drilling a relatively medium size hole in the middle of the screen inside the cats.

Anyone done this before? Any tips or experience you'd like to share?

Sube

iTrader: (14)

I had to gut the cats on my car since the passanger side blew itself out. We unbolted the cats from the manifolds and y-pipe, and i think the drivers side we had to cut off since its welded onto the y-pipe. We just took a hammer and screwdriver to it and cleaned them totally out. It definately made my exhaust louder especially at idle with LM catback.

Xtnct00WS6

iTrader: (8)

How do you think it'd affect the sound if I drilled a hole the size of a quarter in it? Would I fail a sniffer test if that's part of my emissions...?

co.6z28

iTrader: (1)

if your gunna go through the trouble of taking the cats off you should gutt them completely.

strokedls1

iTrader: (1)

It won't pass the sniffer if you drill it out.

My90Iroc

iTrader: (26)

Don't bother just drilling a hole through them, what'll happen is they'll heat up and fall apart and all that crap will have to blow out through your exhaust system. Just hog the whole thing out if you're gonna do it.

No, you most likely won't pass the sniffer but if they have OBD-II testing (just plug into the computer) in your area there is no sniffer so you're set.

SVThis

iTrader: (2)

i wouldn't do it if you plan headers and reuseing them afterwords....i put midlength headers on my LT1 and gutted the cats with a magnaflow catback and even though its not raspy it backfires like i dont know what...its an A4 with 3.73 gears so i run about 2500 rpms(give or take some) at 60 MPH when i let off the gas it backfires a lil which sounds decent....but when i rev it my god it backfires LOUD like 5 or 6 times...

DONAIMIAN

iTrader: (18)

I say just go to a "friendly" muffler shop and have them replace them with straight pipe.

SLP/Drew

had the same problem when I got my headers installed...Some times you have to get a computer tune after a full exaust mod like that because it messes with your o2 sensors and your comp is not use to that much backpressure being relieved