To my surprise while replacing a 3" but very pieced together exhaust system I found that the cat had been hollowed out. Is this going to be much of a problem? Aside from legally.... I already got it inspected and they didn't notice and he banged it around pretty good. I'm mainly curious about power, reliablity, and gas milage effects.

 

usually more power.. i would assume better gas mileage, and reliabilty, i see no problem.. the only thing is you will want to replace it before the next time you get the car tested for emmitions. it's kinda needed.. stupid ozone.


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If it breaks, it wasn't good enough anyway.

 

If you replace it you'll gain some low end torque, but lose some high end horsepower (I'd rather have the torque in a street motor).

If you've got EFI then emissions doesn't make much of a difference, the 02 sensor tells the computer what the mixture is and the computer adjusts it for the maximum fuel economy and lowest emissions, cat or no cat.

If you've got a carb you'll need to tune it correctly, it happens to be that the proper mixture for max power is pretty close to the lowest emissions (most efficent).

 

Ok... I don't have emissions testing here yet. Just an over all safety and equipment check. The motor is TPI and seems to run fine. I guess I'm not going to worry about it until I get the headers.. then I'll just go with a 3" High Flow. Thanks guys.