I was going to remove the muffler off of my 2005 Silverado and run straight pipe from the cat back. The guy at the muffler shop said this would cause the cats to fall apart in a few months due to the extra fuel that is being added into the engine because the downflow O2 sensor will think the engine is running lean. I know people that have removed mufflers and run straight pipe and have not complaigned about anything like that. Has anyone out there run into this or is he a little off? Thanks.

 

Sounds like the guy at the muffler shop is pulling your leg. Sure your O2 sensor will respond differently but I really doubt its gonna tear up your cad converter that fast. I have straight piped many trucks with freinds and have never heard anything like that.

 

I can't imagine you will hurt the cats, but say goodbuy to lowend power. You need the backpressure made by the mufflers to keep the low end power.

 

i dont see how removing your muffler would affect your cats at all... i know several (10 ish) people running cats with no mufflers and they haven't had any problems at all... other than loss of low-end power, but thats different

 

I am not sure the loss of low end power is true. I ran around with the back end of my exhaust unbolted for a couple of days and didn't notice any change. I'm not saying you don't loose any torque but it seems to be so little that it doesn't effect performance. It would seem to me that the Cat creates most of the back pressure because of the stuff inside of it.

 

yeah i lost a LOT of backpressure cutting my cats off, and i still have a muffler

 

You must not have to worry about emissions where you liveif you cut the cat off your truck.

 

nope. west tn, no emissions tests

 

I bet if you drove it with the stock exhaust in place at the track and then drove it without the stock exhaust in place your times would drop. Mine did. And I'm talking like 4 passes back to back when it was stock vs. 3 passes afterwards.

 

You guys are slammin everyone who wants to free up there exhaust, but i worked for a wrecking yard for like 5 years andyou wouldn't believe how many motorsI've seen ruineddue to clogged cats, all that back pressure destroys the rings.I would give up my bottom end powerfor the top end any day with these motors. Get a Duramax if you want torque. I have a 6.0 and even that motor doesn't make good power until 4500 RPM's, no sense worrying about the bottom end. So to all you guys who love the loud exhaust sound, Go for it cut it all off. And for the o2 sensor problem at the beginning of this thread Thats BS. It sounds like this guyat the shopis a carb and points kinda guy, and dosn't know about fuel injection.