Topic: ditch the cats?

[jvanian]

I have flowmaster 40 series on my 07 avalanche but i want a little deeper and louder sound.  Would you guys reccomend taking off the cats and putting a pipe instead? I got a quote for 50 dollars...what problems would i get into with this? I kno it is illegal

[oHIobellboy]

You'd get all kinds of codes from the o2 sensors unless you shut them off.

[MonstaMonsta]

I had mine hollowed out and am moving towards having them "cut out" so that I can weld in pipes.  On my 02 I really do not feel that hollowing out the Cats makes a whole lot of a difference in sound.  Only reason I'm having them cut and pipes welded in place is because I'm afraid of the turbulance that might exist in the empty Cats....   My CEL is on, but I'm not sure if it's because of a bad knock sensor or even bad oxygen sensor...  I'll fing out as soon as I get this OBII reader.

[MyBigToy]

If I was going to do it, keeping in mind I have to pass both an OBDII and visual inspection, I would cut the cats out, hollow them out, weld in a pipe on the inside of the hollowed-out cats, and weld the cats back in place. Like OBB indicated, you will throw codes if you don't have a scanner or software to turn off the rear O2 codes.

[Main One]

If it is more sound you are after, keep the cats and go mufflerless.  I've heard an AV that was set up that way, and it wasn't all that obnoxious.  The owner sure liked it!

Chrysler used to sell brand-new "tuned" Neons without mufflers so it isn't all that unusual.

[Damballa]

I did this in my old '98 Regal GS and there is was a "O2 Simulator" available that when you pulled the cat, you replaced the O2 sensor with the simulator and it would let the pcm think there was still an active sensor.

I'm not sure if these are widely available for the Avalanche, but could be an alternative if you can't get ahold of something to delete the codes.

[Ski Edition]

If it is more sound you are after, keep the cats and go mufflerless.  I've heard an AV that was set up that way, and it wasn't all that obnoxious.  The owner sure liked it!

Chrysler used to sell brand-new "tuned" Neons without mufflers so it isn't all that unusual.

   Would love to hear a mufflerless AV!!   

[MyBigToy]

I did this in my old '98 Regal GS and there is was a "O2 Simulator" available that when you pulled the cat, you replaced the O2 sensor with the simulator and it would let the pcm think there was still an active sensor.

I'm not sure if these are widely available for the Avalanche, but could be an alternative if you can't get ahold of something to delete the codes.

The Feds shut them down about 5 years ago; they are no longer available.

[Main One]

Damballa is from Canada - maybe he can still get them up there???