I must build a great big camoflage canopy and hide in my Jeep under it whenever I bring this up, but will tell you what I did for several years and why. I was poorer than your poorest church mouse and was sick of sinking the money into a full tank of gas for it to only last 220 or so miles. I noticed that there was a nasty lack of exhaust and was hard to get going on the road and no power at all. I recalled 350-400 miles per tank newish and had all intentions of getting something close to that. At first I figured the muffler was shot, not to say bored or anything, but clogged. So, after several hours and many conversations with Jack and Johnny, I managed to get the muffler loose and off. Fired her up, no change. Pulled the CAT off, WOW!!! sounded like a dirt-track race car! Drove home at such a late hour, I was sure someone would complain about the noise, but coasted as much as I could. I hollowed the CAT out using a length of rebar and reinstalled it, went to the local parts store and got a straight pipe "muffler" (cherry bomb with nothing more than mesh in it to keep the rats out) and some flex pipe and managed to get the end of the pipe to "exit the vehicle". Ran it like this for several years, with about 375 miles per tank! She's nearing 220K miles and runs pretty damn good! Eventually, I had the money to buy a new muffler and by this point needed to replace the header since it was cracked pretty bad, new tail pipe and sure got quiet! She's down to around 300 miles per tank, but my neighbors sure do appreciate the quiet approach rather than before. I did have to have the muffler to get a Virginia state inspection, so, was glad to have it. They didn't say word one regarding emmissions control, so, still running w/o the CAT. They really are good for the environment and I will replace it with a functional one eventually. I only drive her to the beach and to the farm to go fishing, so, I really don't feel that I'm killing too many of the already filthy air particals out there. Fact, BJ said it quite well in another post that headers suck whats in the cylinders out so more gas can get into them, causing less mileage. If your vehicle came with a CAT, it's sposed to keep it. If you have a CAT that is functioning properly, it will help reduce the harmful "noxous gasses" from making their way to California where they really don't like them. Whew, that was fun, hope someone got something out of this.
