Exhausts & Cats

Hey guys,

So I've got my flange to start building my 3" exhaust. I plan on having the exhaust done in sections, so we can dB test at each point to bring it just under the legal noise margin using as few resi's as possible.

Cats on another hand, I've heard people talk about different cell counts, hi flow, sports all this different stuff. Near as I can figure it all means about the same thing, but could someone please give me a bit more definition on these?

I've seen things like the 100 cell flows a bit higher, but could cause boost creep (I find this unlikely) and have a shorter lifespan. Also seen that they may not be legal, however I fail to see how a cop would be able to distinguish 100 from 200 when looking under the car unless it's blatently embossed in the metal (again doubtful) and even then the cops could never tell the straight through pipe with an empty cat housing welded around it on my N13 turbo.

I dont know what the laws are over there, but if you go for a 100cell cat, and you get caught, you are up for a $20k fine, maybe more. And its not hard for a cop to get the EPA down to test your exhaust emissions on the spot, thats how they find you out.

hi flow is exactly that, the less the cells, the higher the flow (but also the higher the emissions), sports is pretty much the same definition.

Never heard of boost creep so cant help you there. My opinion... Just play it safe and get a 200cell which is perfectly legal and you wont have the worry of "will i get caught or wont i" as its more than enough, and i guarantee you will feel the difference.

Right... good info, thanks Adz. 200 cell cat it is then...

Got my 200 cell S/S sports cat off ebay, someone in Brisbane (ExhaustQueen rings a bell as the username)

Cost ~$180 delivered to Sydney. Can't go wrong...