3 Cats?

Visegrip117 · December 30, 2009

I was looking under my truck (09 sierra 1500) and I saw, what I believe to be, 3 catalytic converters.

There are 2 up close to the motor ( one on each side) and after the pipes merge back into 1 pipe there is another.

Is this correct?

Now my 2nd question. Could you remove the 3rd cat without causing any problems. Such as sensors and such.

The cats close to the motor have sensors near them, but the 3rd one doesnt.

Now my 3rd question, Would this even help if it can be done? I would think it would allow for more of a free flowing exhaust , with less restriction. But then again, I'm no mechanic

Any thoughts are opinions are welcome

dlewis1111 · December 30, 2009

I think you may be looking at a resonator instead of a third converter. Are there any o2 sensors installed in this "third" converter. Parts diagrams show just two converters...

Metro12 · December 30, 2009

I would not mess with cats. You could be in for one heck of a fight with your emissions testing, when they see its missing. Also, I don't think removing one would make much of a difference. I have nothing to base this on, just taking an educated guess.

Visegrip117 · December 30, 2009

I think you may be looking at a resonator instead of a third converter. Are there any o2 sensors installed in this "third" converter. Parts diagrams show just two converters...

This may be true . Whats the point of the resonator?

VMax2007 · December 30, 2009

This may be true . Whats the point of the resonator?

Sound control.

jrod332 · December 30, 2009

resonators are purely for silencing. It cancels out certain sound waves.

mattgob86 · December 30, 2009

yup and then it should have a flex pipe and then a muffler and then something else on the other side of the hump, the 09 exhausts are "loaded"

Visegrip117 · December 30, 2009

yup and then it should have a flex pipe and then a muffler and then something else on the other side of the hump, the 09 exhausts are "loaded"

Yep, I saw the flex pipe and the muffler

What exactly do you mean by loaded? Sorry if this is dumb, Not up to date on the lingo

mattgob86 · December 30, 2009

I mean my 6.2 has the two cats, the resonator, the muffler, and something else and the flex pipe its just alot for an exhaust. Looks busy under there. Plus mine is 3.5 inch all the way FTW

09Jimmy · December 30, 2009

The third one is a cat. Check out this thread:

http://www.performancetrucks.net/forums/sh...ad.php?t=436526

mattgob86 · December 30, 2009

Not that I think one way or the other but they kinda dissagreed at the end of that thread about what it actually is. It looks like the smallest cat ever and I think the resonator is the can on the other side of the axle. I thought it was a cat too.

Visegrip117 · December 30, 2009

So the debate continues. . . . . . .

jrod332 · December 30, 2009

Its definitely a resonator.

Whocares05050 · December 30, 2009

Its definitely a resonator.

It 100% is NOT a resonator. That is absolutley a cat converter.

Its there just to burn up what the other two didnt for newer emmission ratings. From the look of it OP, I dont see any secondary 02 sensors behind it, so you can take it off with no problems / CEL's. It will make the truck a little louder though. Keep the flex tube, its there to support the exhaust to move probably due to so little hangers.