Cats (good or bad)

[M3SMG]

Do you think taking the cats out of the exhaust, would be harmful to the car?

And has anyone done this?

 

[///M SPEED]

I don't know if you state requires an emission test, but would it pass if it does. I know the State of Washington requires one and I am not certain the car would pass without the cats....

 

[jrt67ss350]

It won't be harmful to the car, but you'll never pass emissions certification if your state requires it (you won't even get past the visual inspection). You also aren't going to see much as far as gains go - modern cats really aren't all that restrictive at all. You'll also constantly have a Check Engine light on if you take them out.

 

[adamsonem]

Cats are good (found this online)

On a serious note, it won't be harmful to the car. You'll fail the emissions tests before you even start them (check engine light = fail), and if you make it past that, you'll fail the visual underbody check. If you make it past that, the numbers don't lie.

 

[Tom]

Cute cat picture Evan.

It won't be harmful to the car, but you'll never pass emissions certification if your state requires it (you won't even get past the visual inspection). You also aren't going to see much as far as gains go - modern cats really aren't all that restrictive at all. You'll also constantly have a Check Engine light on if you take them out.

^^^I completely agree.

 

[M3SMG]

Cheers for that,

But where I live is in the channel island (Jersey) and over here once you have collected your car you dont have yearly test.You can do what you want to it.

The thing I was worried about was that I heard that the ecu goes into save mode when you take the cats out, if it did do that how do you over ride it, is it foot on the brake then disconnect the battery?

 

[Chesty Bonds]

Well I don't want to be a wet blanket or anything but the cats are there for a reason: to help reduce emissions and pollution. Given the current state of the world's climate I would say it's probably in our best interest to keep them on...

Damn I'm sounding like an old fart already!

 

[JGM3E3632]

I took the cats off of my car, replacing them with AA Tunning track pipe. They include o2 simulators for the sensors that are after the cat. So the sensors tell the ECU that they are filtering out the emissions. It makes the ecu think that there is cats back there, but it is just a resonator. As all of you guys know the mixture is measured at the bottem of the exhaust manifold flange. So the ecu still measures the mixture. As for performance gains, yes there a moderate power gain. I'm happly with it, it also made the car sound better.