7th gen V6 Cat Question

[Conundrum]

Well, I've decided to bite the bullet and buy one of Richie's J-Pipes from the GB going on at V6Performance...but I'm still debating if I want the test pipe or not (since I can get it with the test pipe or without). Essentially the test pipe will replace the 3rd catalytic converter, allowing or more power, better flow, etc, etc...

Anyhow, although I know its probably not exactly smog legal to remove the 3rd cat, my question is, does anyone know if the 3rd cat on the V6 is used to just make the engine cleaner than it would be with the 2 cats mounted directly to the engine (in other words, makes a clean car even cleaner)? Although I always love the idea of more power, and the test pipe is easy enough to replace with the real cat when testing time comes around...I don't want to pull it if its going to make my car into a big polluter. Since the 2 cats on the engine are called "precats", I'm just trying to figure out which ones (either the first two or the 3rd) do the grunt of the work...since I want to leave that one well enough alone.

So, if anyone knows please post...I'm putting the $100 dep down for the J-Pipe with test pipe tonight, but I could always pm Richie and tell him I don't want the test pipe anymore and modify the final shipping price.

Here is the two threads on V6P if anyone else is interested (share the wealth kind of thing...the gains look amazing):

http://www.v6performance.net/forums/showthread.php?t=99114
http://www.v6performance.net/forums/showthread.php?t=99609

[nicepeta]

you want more power = no 3rd cat.
or yes, change it to a test pipe.

[Conundrum]

sort of "bump"....

I know pulling the 3rd cat will net more power, but I am just wondering what the environmental impact would be. I'm always down for more power, but not if its gonna mean my car is polluting badly and should be pulled off the road.

J-Pipe has been installed, but I left the 3rd cat for now and the test pipe is sitting in my room until I can figure this all out. Everything I find on the Internet says that the two cats close to an engine are precats, and only clean the emissions on startup assist the 3rd cat once the engine is warm and at speed. If this is the case then I don't want to pull the 3rd cat, since it does the grunt work on a warm engine.

Now, in the above, the 3rd cat is always monitored, since pollution = bad, therefore the sensors cause the car to throw a CEL, and you'd bring it in to be serviced. Now on the 7th gen V6s (and prob 8th gen too), the 3rd cat is unmonitored...meaning I could weld a pipe there and the car would not tell me there is an "error" in the emissions control system. When my mechanic mounted the J-Pipe, he said that the 3rd cat looked like a car and not a resonator...but couldn't figure out if it was a real one, since it might just be there to pass a visual inspection, as it has no wideband or O2 sensors near it...and on most 3 cat layouts the precats are unmonitored and the 3rd cat is monitored, or all 3 are monitored.

Anyhow, long story short, does ANYONE have a way of confirming this with Honda? My mech wouldn't say one way or the other really (was an ind shop), since he didnt want to tell me its not a cat and I'd be fine to remove it, in case I got in trouble...but he didn't want to tell me its an important part either. Really, I want a clean car, and if that cat only makes a clean car cleaner (to pass CA emissions) then I'd pull the cat for power...but if it does most of the cleaning, I want to leave it in place.

[stevencrosbie]

I thought you were buying a WRX?

[Conundrum]

I thought you were buying a WRX?


Me? Nope...never said I was (although I might have mentioned how I used to have a friend who owned a 2006 2.5 Impreza). I know someone else is buying one in the V6P thread though. After driving one of the loaner 335xi's one of my friends got while his 330 was in the shop, I figure that might be my next car (or some turbo-variant of the next gen 3-series) when I do decide to buy another car.

[KunalPatel87]

I thought you were buying a WRX?

That's chanke4252. Haha.

[stevencrosbie]

That's chanke4252. Haha.

Damnit...sorry man...didn't meant to confuse you to :) I should know better as Canada isn't very close to Indiana :)

[Aviography]

Conundrum,

Think of it this way:

1. Why would Honda spend the extra money on design and tooling to make a fake looking cat. converter? EPA doesn't care about how the exhaust system looks, they only care what's coming out from the back of the exhaust pipe, so there is no doubt it is in fact a cat. converter.

2. My Honda factory service manual describes the two converters right off the exhaust as "front/rear warm up three way catalytic converters", and the one downstream as "three way catalytic converter", one more proof that it is a cat. converter, unless you still believe the conspiracy theory and that Honda made this thing to look like a cat. converter to fool Arnold Schwarzenegger and the Californians! :)

3. It's unlikely the small amount of horsepower you will gain by substituding the 3rd cat. converter with the test pipe is worth the hassle to have to re-install it every other year for the emission testing.

Most of all, it sounds like you are a "tree hugger" at heart and feel guilty about removing it, otherwise you would never have asked this question in the first place.

So, now all the facts are presented, leave the 3rd cat. on there!

Lastly, how's the J-pipe working out, noticeable gain? any before/after dyno chart?