Hey guys, I want to do some cheap work on my exhaust system to bring out that rumble, and up my efficiency and horsepower a bit, but I'm not looking to spend big bucks. Dropping $700 on my Fiero's Borla exhaust was one thing but the 2.2L Sunfire . . . lol it just ain't worth much effort.

So I was thinking straight pipe in place of the cat and a glasspack basically. There are no emissions tests to pass out here in the boonies so that doesn't really matter, and I don't care much about looks. I figured I'd just save effort and use the stock exhaust piping (what diameter is it?).

So my question is this: there's a second O2 sensor after the cat, right? Can I get around that or do I have to install a high-flow cat (not a straight pipe)? I don't want my "check engine" light on when everything is fine except the O2 sensors are giving erratic readings due to the straight pipe. It's like the boy that cried wolf - I want that light on only when there's a real problem.

Also I'll ask, would this be completely stupid to do? I mean, is it ridiculous to do this but not get bigger pipe and go through all that trouble? I don't know these Sunfires, so you tell me.

Thanks in advance!! If you wanna tell me what you've done to your exhaust, BTW, I'd love to hear it.

On a stock 2.2 the cat. conv. will give it enough back pressure so you have some low end torque . I would say replace the resonator and check on a good magnaflow muffler . People seem to be happy with them .

Yes there is a second O2 sensor after the cat. conv. and the only real way to get around it is to pick up an O2 simulator . If you are going to get rid of the cat. conv. then you could pick up an O2 bung and weld it into the pipe to install the sensor back into the exhaust .

As for what I did on my exhaust


I used stainless steel mandrel bent pipes and straight pipe . I am running 3" all the way back from the exhaust flange ( had to make it because no one would seel me one ) . I am using a 3" in / 3" out magnaflow cat. conv. into a 3" in / 3" out magnapack resonator ( 36" length ) . From there it goes into the flowmaster series 80 3" in / 2.5" out muffler , and out the tail pipes which have a set of 2.5" magnaflow tanabe double wall stainless steel tips . Since I had to remove the heat shields under the car I wrapped the crucial areas with header wrap to cut down on heat around the hoses , power steering and gas tank .

No the rod on the muffler is'nt going to stay on there . It was used to hang the muffler while I figured out the pipe length and bends needed .

How did I get around not using the second O2 sensor . I am running a stand alone system which only needs one O2 sensor . So the second one did not need to be installed on this exhaust .


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