will i hurt anything but cuttin out my catalytic converters and welding in straight pipes

 

yea cuz your oxygen sensors are i there to adjust the fuel to air ratio so it would mes up some shizzle. i would go buy some high flow cats instead.

 

yeah but the oxygen sensors are before the cats. arnt they

 

mmm there might be one but im sure there is one in the first cat. just go under and look it should be a little wire going into the cat and on the passenger side of the truck

 

You can cut out the cats, but you will have to get Mils for the O2 sensors after the cats.

 

You could always get o2 simulators, for off road use.

hxxps://www.casperselectronics.com/Merchant2/merchant.mvc?Screen=PROD&Product_Code=104039&Categ ory_Code=Expedition

(replace hxxps with https)

 

[QUOTE=daveplot]You could always get o2 simulators, for off road use.

https://www.casperselectronics.com/Merchant2/merchant.mvc?Screen=PROD&Product_Code=104039&Categ ory_Code=Expedition[/QUOTE]

Link does not work. Are O2 Simulators the same as Mils?

 

I fixed the link

My brother had to use them on his Trans Am after changing out the headers and exhaust.

 

Hmm, they must be the same thing.

 

I'm pretty sure it's a federal offence to disable the Cats on an on-road vehicle. I was told once it's something like a $1000 per cat per day if you get caught. You might want to look into it before you go ripping them out.

 

You should have two sets of O2 sensors, one set before to take readings of the exhaust gas, then one after the cats, to compare to the first readings, and then adjust A/F ratio accordingly. Removing your cats completly will screw up the comparision and throw a check engine light. As long as you have it set up that way you will continue to throw a light. The only way to get around that is to get a MIL cheater. It's a little black plug that plugs into your O2 Sensor and then you plug the harness into it. It sends a false signal to the computer, making it think everything is O.K. in the O2 sensor area, and prevents the check engine light. But it does not fix anything, you will still pobably run really rich unless there is a cat and a properly working O2 sensor in there. Most Off-road pipes come with a MIL cheater and you can buy them separatly too. They are usually about $40-50.

 

Yeah, it's a pretty beefy fine if you get caught without cats. Some people seem to think that since their state doesn't do emissions testing they can get away with it, but these are Federal laws, not state laws. I ran my Focus for 2 years without cats, and I got pulled over twice in that time, and both times I was sweating bullets hoping they didn't want to go snooping around my car. And since California is now a dictatorship government I would have been doubly screwed. Besides, a good high-flow cat makes just as much power and sound as no cats. Sure they cost more, but weigh the intial cost of the cat against paying outrageous fines.

 

Actually running without cats will not effect the performance of you vehicle, even running the rear O2's disconnected will not effect the vehicle performance. You WILL get a SES light without MILs in place though. The rear O2's measure Catalytic Efficiency, based on a reading of 0 to 1 volt. The computer is looking for a reading of between 3 and 6 mili volts to let it know everything is ok (cats doing their job). A Mil Eliminator is nothing more than a resistor and a capacitor. Basically it takes the "rich" condition (readings above 6mV) and converts it to an "ok" condition (reducing the voltage to the computer by 1/2, bringing the readings back into the normal range (3-6 mV).

Yes, Federal Emission Law fines are expensive, but they deal more along the lines of "tampering with" than the actual act of running without. They are also more geared towards shops that remove such devices and not the individuals. Individuals are left up to the State laws in most cases, and here in Texas (depending on County) the fine runs about $200 per offense.

I do agree though that a good set of high flow cats will give you almost the same performance and sound that an off-road exhaust will, and it is much less worry going this rout. One thing though with some aftermarket high flow cats, is you still may need to use Mils.