catalytic converter?

[chacho44]

removed mine and the truck sounds fine, very little diff in sound but still running stock muffler

 

[Jay]

Modern converters do not rob enough power on a bolt-on vehicle to be worth the trouble of removing them. Like anything else they are designed for a flow rate. The stocker might cost a 5.3 5-10hp at 5k rpm, and considerably less in the lower rpm. The stock muffler robs a lot more than that. If you mod a stock 5.3 or 6.0 to 400hp it'll keep up fairly well. At 500hp (assuming you are turning 6500rpm or more, or using N2O/boost) then the stock converter probably will be eating a lot of power (20hp+)... there is a sharp break-over point to where it really starts robbing power as you increase the flow rate/load rate due to turbulence (study up on Reynold's number for fluid flow).

Personally, for a road vehicle I'd rather keep the cats. Just size it/them to the power level and not have to smell those rancid fumes.

 

[TogaPC]

^+1

 

[sstuck2]

removed mine and the truck sounds fine, very little diff in sound but still running stock muffler

hey man, hate to revive this ancient thread, but I have a 03 z71 tahoe and I want to cut the cat off but i dont want a check engine light on all the time. Did you have any issue like that?

 

[DCT]

hey man, hate to revive this ancient thread, but I have a 03 z71 tahoe and I want to cut the cat off but i dont want a check engine light on all the time. Did you have any issue like that?

How do disable the check engine light after removing the cats?

 

[franksbanks]

How do disable the check engine light after removing the cats?

a custom tune- you can disable the bottom 2 (post cat) sensors-

the o2 sensor above the cats (pre cat) are needed for the truck to operate-

if you dont want to spend 399+ for a tune- the alternative is to use o2 simulator/Eliminators (google search) to keep the voltage registering that theres an o2 sensor actively working.

 

[livingez_123]

Federal offense, your no fun.

The smog check here in Portland, OR is a simple plug in the OBD port and a look with a mirror under the truck to see if the cats are there.

 

[Gzes]

We only got safety inspection here I un gutted cat

 

[jmgak47]

Removing the cats should give you roughly 8 or so hp to the wheels, a slight loss in throttle response and a CEL.

You can eliminate the CEL with custom tuning or spark plug nonfoulers, a cheap alternative.