I have a 2004 EX v6, AEM CAI w/ bypass valve, 2.5" straight piping from the cat w/ flowmaster original 40s on the end. I was wondering if a high flow cat is worth the money or will make any significant difference in power or sound. I've heard from some that a "high flow" cat is bs but I'm still a noob to be honest. Any help is appreciated, thanks.

 

Beware of fake "hi-flow" cats that are really just a blank test pipe. Especially since you're in CA (the land of smog testing).

 

They do make TRUE high flow cats. But they are like 300bucks. But they are real. But yes when ppl say high flow cat they are most likely talking about a ebay test pie you can buy for 20bucks. I mean I have a ebay test pipe on my cb7. If you don't live in a state that dose the smog testing then you can use one. It relieves a good bit of back pressure. But you don't need on unless you have some work done. just taking your OEM cat on and replacing with a test pipe won’t gain much of anything. But if you live in a state that dose smog. Then look into a REAL high flow cat...they have a better exhaust flow than a OEM cat. Flow master makes them. Magna Flow makes them I'm sure there is more company’s who make them too.

 

Yeah I'm in Cali, so I'm screwed over in a lot of ways haha, so no test pipe. But with an OEM Cat I'm guessing I'm looking at close to $350-500 for parts and labor? Is it really worth the money in anyones opinion?

 

I don't know if the V-6 (stock) really has a restrictive cat. A high-flow cat can only improve to the extent that the stock one is restricting.

Now if you've done engine work (cams, blower, high redline, whatever) that actually makes a lot more flow, then maybe it's needed.

 

It’s only worth it if you need less backpressure form modifying the engine. IF your stock or close to stock don't bother. I'm not talking about blot ons either. That to me is stock.

 

Yeah, I don't really have serious engine mods, it's close enough to stock, so I guess it isn't worth it at the moment. But thanks for the help.