removing cat
 

i have a 97 250 with 460. i have the muffler cut off at the cat, and has been that way for a few years. what would happen if i removed the cat? the O2 sensor goes to the cat, can i just leave the O2 pipe hanging in the air? will that kill my mileage? thanx

-jason

this truck a obdII mass air ?

what about emmissions?

no, it's w/o mass air
-jason

It will be loud as hell. That O2 sensor is just for monitoring CAT efficiency... so the check engine light will come on.

you can also get o2 sims for a decent price. they are easy to bolt on and they will make that annoying light go off

It is a visual fail for an emissions test (if you have it), so just pay the $25 for the test and as soon as they see the missing cats you get a F.

One thing I have heard of people doing is removing the cats and then boring a hole in the cats with a broom stick. It is a brittle, honey comb shaped material in there. You need to have enough cat there to pass emissions.

Joe.

a friend of mine hollowed out a cat but left it on...screwed up back pressure and gave him crappy gas mileage