the exhaust guy left the cat on my '02, he did a 4" stainless - turbo back.
does taking it off make much difference to the performance or eco???:(

i don't know how it is in ca but in wis alot of shops wont remove cat for the fact that if it cam from factory with it.. it is illega for them to remove it. but where i'm from if you take them a new truck and it "fell off":lol: they will put a whole system on for you.. don't know if it applies to diesels but this was the game on gassers.. i helped alot of them fall off before my buddies went in for a new system.. and yes it does make alot of difference.

Emission systems fall under Fed & State laws. Reputable shops, that wanna stay in business won't mess w/emissions systems. CA Dmaxs have had egr/cats since 02. 01/02s looked identical and we could pass off our 02s as 01s should someone ask.

While I've not seen any definitive study on performance effect of removing the cat ~ I'm thinking that it would be minimal. Our mindset about cat's tend to be skewed by our early experiences w/them on gasser applications ~ decades ago. Me thinks the newer tech cats are freer flowing and less restrictive than ever before. One would think any diminished performance would likely be attributed to the egr moreso than the cat. Then again, what do I know

~ Shummy

I didn't think the 02's had a cat :confused:

02's had had cat's but only in CA