if a cat was punched out, would it cause any negative effects?
any back pressure issues?
would it cause the SES light to come on?
would it do anything to the O2 sensor that is behind the cat?

"The fuelling curves designed for cars are mapped for the back pressure presented by the catalytic converter and exhaust system."

 

I punched out my cat ( I'm not condoning animal abuse though) with no negative effects. No light, no noise, and with a Y, B-pipe seems to pull a little harder and smoother throught the RPM range. I'd be VERY careful eith this because of the emissions test in VA ( I lived ther for 15 years). Good luck.

 

im actually in the military so i still have oklahoma plates and dont have to get VA inspections.
so improvement was in performance with no sound? i already have a y-pipe and was kinda wanting it for both. to increase airflow for performance with a little more sound.

 

What does your cat look like? Mine looked like a football. Since you have a Y-pipe already I'd consider a cheap B-pipe (warpspeed) to complete the exhaust. There is a deeper tone but nothing that is annoying, that's something I didn't want. I was in the NG at Davidson Airfield by Ft. Belvoir for 8 years as a Crew chief on a Medevac Chopper. Good luck.

Kirk

 

it looks like a mini muffler. i can just punch it out with a broom handle right? i looked inside it and it just looks like a filter.
im planning on getting the b-pipe or at least a new muffler (powertech)

 

Yep, a broom handle will do it. Wear a face mask cause it gets kind of dusty.

 

so kinda like a vaccum cleaner bag?
ill probably stick it in a trashcan so all the inside stuff goes straight in there.
thanks for the help

 

The Cat is pretty expensive to replace, so why destroy it? Since you have to remove it anyway to hollow it out, why not just get a test pipe or a customize straight pipe to replace the Cat.? You can actually sell the OEM's Cat or save it for later use when you decide to go back to stock.

 

i want it to "look" like i have a cat. i dont have to get inspected but was worried about if for some reason a cop checks and sees that i dont have one.
and im pretty sure it is illegal (or frowned upon) to sell a used cat. but i guess so is not having one

 

Tampering with emission control devices (such as catalytic converters, exhaust gas
recirculation valves, air pumps, etc.) is illegal. This antitampering law applies to individuals
as well as to businesses. Individuals may be fined as much as $2,500 for each vehicle
tampered with, and businesses are subject to fines of up to $25,000. Note that businesses that
sell used vehicles must ensure that the vehicle is equipped with all emissions control devices
that were originally installed by the manufacturer.

 

I haven't seen to many cops on their hands and knees looking to see if you have a cat... but those Fairfax County Cops are a tough bunch. I agree, appearance is everything. Other than tapping on mine and hearing the hollow sound, it looks absolutely stock. Living where I do and seeing the POS cars & trucks blowing all their smoke & crap, eliminating 1 of 3 cat's on my emission loaded car doesn't seem to environmentally unfriendly.

 

i still want to know what the sensor is BEHIND the cat does.
this is what im thinking - it checks the exhaust diffirence after the cat and compares it to before to see if the cat is working.
so if i punched out the cat, the exhaust would be the same and would make the SES light come on for a bad cat, right? then wouldnt the ECU change the fule/air mixture?
i just dont want to punch it out then have to buy a new one because im getting bad gas mileage and lost power!

 

My 02 sensor's are in front of the cat, it would seem logical that the sensor behind the cat would compare the readings before and after the cat and might throw a SES light... don't know for sure. The ECU is constantly adjusting air/fuel given the driving conditions, so I'm sure it could compensate for the lack of a cat. I eliminated mine about 2 months after I got it new and have had no problem with fuel mileage, loss of power, noise, and SES light, guess I'm lucky. Mabye you can pick up one up from a junk yard if the price is right and work with that one. My .02, good luck.