I was wondering if anyone has ever gutted their OEM cats? What are the pros and cons in reguards to this mod? Lastly, will gutting your OEM cats create a raspt sound in your exhaust system? Thanx in advance for any and all response to this thread.

 

I'm interested in this, too. High flow cats and test pipes make the Nismo exhaust far too loud for my tastes, but I'm guessing gutted cats (basically a double resonator test pipe) would quiet things down a bit. There are lots of people around here who've gutted their oem cats, but I'm not sure anyone has commented on loudness compared to ungutted oem cats.

 

it takes an assload of time to gut the oem cats. i know because i have done this about 3 times. good luck if you do, if not i got a spare set i am gutting this next week if you guys are interested
at the last dyno day, someone had gutted oem cats, TS headers, greddy evo2 exhaust. the sounds wasnt raspy really. i'll see if i can dig up the vid

 

will it be better than the test pipes (performance wise)??

 

"The sound wasn't raspy really", So it does exzibit a little bit of raspt? Should i be concerned about this or do you think that it isn't really that bad. I don't want my Z to sound like a Honda. Not to concerned about the power gains though because it will make power either way so i'm more concerned about the sound. Thanx.

 

car with headers, gutted cats, evo 2 exhaust:
http://islide.net/z33/dynoday1/vids/...%20nitrous.wmv (right click save as)

my car with headers only:
http://islide.net/z33/dynoday1/vids/...%20daytona.wmv
(right click save as)

as you can hear, the car actually sounds deeper than mine without any rasp. mine actually sounds like it has more rasp since the car is higher pitched.

 

if you are concerned about rasp and want to run test pipes. People are having good luck with the Labree resonated pipes. I have these on my car and I get only VERY SLIGHT rasp ocasionally. I wouldn't gut your stock cats unless you can get an extra set.

 

Thanx guys. Where can i find these Labree test pipes? How much do they cost?

 

I don't know if they are available from any retailers, but I am sure you can get them from Labree Motorsports

I think they are around $300 now - I bought mine from a member back in October for more than that, but I think they have come down in price since then.

Here are pics of mine:




In this pic, you can see the extra bung for an extra sensor like a wideband o2.

 

That first clip is a pretty good representation of what the evo2 exhaust sounds like. I tried making a clip with my digital camera, but the sound didn't really come through that well. With my headers and labree test pipes, it is slightly louder and slightly deeper than that, but that is a good clip of what the exhaust sounds like in person

 

so, still, which is a better performer and sounds better?(gutted or test pipes)

 

I'd say that it depends on your exhaust. Some exhausts get *very* loud when you put on test pipes, even resonated test pipes. Others sound just fine.

 

Test pipes should provide better gains as I would think gutted cats would cause turbulence in the exhaust flow. In terms of sound, I would guess it would be a factor of resonated vs non resonated testpipes and what exhaust your are working with.