Eliminating Catalytic Converters

[Evansamms]

Vortecman, The ones i installed werent the real high-flow ones, like you see, just a round tube. They're a replacement style from magnaflow, (dont remember the model number), they look very similar to the stock ones, a little beefier, and claim to flow some high percentage better. I dont remember exactly which ones they were.. but somethin like this link. And i've not had atrouble code since.. . -8000 kms or so

http://cgi.ebay.ca/MAGNAFLOW-CATALYT...QQcmdZViewItem

[ColoradoSilverado]

Originally Posted by dirtdriver11

i was getting the po430 code also, i gutted both cats out and still have the problem. both o2 sensors are new on bank 2

How did you gutted them out ?

Bert

[MT-2500]

Originally Posted by dirtdriver11

i was getting the po430 code also, i gutted both cats out and still have the problem. both o2 sensors are new on bank 2

Gutting the cat is the same as removing it.
The cats have to be on and working or you will get or you will always get a 420-430 cat code on later computer systems.
You need to get some cats on it and make sure the engine is running right.
Miss fire or engine not running right will also set a cat code.
MT

[dirtdriver11]

is there a way to fool the computer system? how does that work with aftermarket exhaust?

[MT-2500]

Originally Posted by dirtdriver11

is there a way to fool the computer system? how does that work with aftermarket exhaust?

Yes there is.
But may be on the border line of illegal.

Some performance chips use what is called a dummie 02 sensor.

It plugs into the 02 sensor wiring and feeds a dummie signal to the pcm to make it think the cat is working.

But I still say for the best performance you need a cat that has some back pressure control.
Removing all backpressure can cause a engine to lose some power.
MT

[silverado122775]

that's right.. ever try to blow or suck through a straw that is too big? same princple.. you need some back preasure to allow the air to flow out properly.

[NoRiceHere01]

its not backpressure thats needed.what is needed is a properly tuned exhaust volume. meaning a tuned pipe length/diameter.this has to do with the pulse of the exhaust exiting the cylinder.the exhaust system is designed so that at low rpm the mixture entering the cylinder is held there by a return pulse of the gases that just exited.removing the pipe or increasing the diamter too much affects this pulse and causes a loss of torque, not necessarily horsepower.at higher rpm you dont want any backpressure because it will prevent spent gasses from exiting properly, thus lowering horsepower.the backpressure of the cats is factored into the design of the exhaust tuning, so yes in a way "backpressure" is needed, but only because of the engines tuning.if the cats are removed and the o2 sensors are simulated, the computer will work right, but low end torque probably wont be what it should.thats why in order to run a straight exhaust system, timing and camshaft tuning really should be changed.however if the cats are in place but gutted, and the sensor simulators stop the computer from showing a trouble code, im sure it will pass inspection.here in new jersey only the computer gets emissions tested, not the actual gasses coming out of the tailpipe like on older cars.this being the case, as long as theres no engine code showing you should have no legal trouble, cause they wont know the cats are empty.im sure your state is the same.sorry to ramble but people ask the catalytic converter question all the time.your question tho is basically will gutting your cats fix your problem and the answer is no.you may not hear the annoying rattle anymore, but the truck wont run right if all you do is remove them

[vortecman]

i think that ended this thread...

[maxwedge]

Good post for sure , to add, any alteration to function of the cat is also a Federal offence. Back pressure is also useful during egr operation, if so equipped.

[vortecman]

why doesn't someone put an end to this argument and DYNO all scenarios (CATS w/ muffler, no cats, no muffler, ..and so forth....)

[silverado122775]

good idea.. we will wait until you are done with the tests