: Is the resonator necessary?



STS127
01-24-07, 04:19 PM
If I were to remove the resonator would I still be able to pass emissions. I've heard that you may get a couple of horses by removing them but my question is is it worth removing it.

chance_b
01-24-07, 06:27 PM
If I were to remove the resonator would I still be able to pass emissions. I've heard that you may get a couple of horses by removing them but my question is is it worth removing it.

By resonator, do you mean muffler..? The muffler shouldn't affect emissions, but you should look into your local laws about noise violations..

If you mean the catalytic convertor, which would make more sense, it would add some horses, yes.. but you would definitely not pass any emission tests. I'm not sure about the newer ones, but I've seen people punch out the honeycomb style ones with a piece of pipe. Basically, the less restricted airflow is into and out of the engine, the more horses you'll get.

danbuc
01-24-07, 06:32 PM
He's referring to the resonator (not muffler, or catalytic converter) located in the mid pipe between the cat, and the y-section where it branches off to both mufflers. Removing it may gain you a little bit of power, but at the expense of more noise in both outside, and inside th vehicle. As for emissions, it won't really affect it that much, since it's after the cat, and both O2 sensors. If your going to go through the trouble of hacking out the resonator and welding in a new section of straight pipe, you might as well change the rest of your exhaust system for something a little less restrictive.

Ranger
01-24-07, 07:57 PM
I would venture a guess that any gain in HP will be undetectable by the SOP (Seat Of the Pants) dyno.

chance_b
01-24-07, 11:25 PM
He's referring to the resonator (not muffler, or catalytic converter) located in the mid pipe between the cat, and the y-section where it branches off to both mufflers.

Whoops, my bad.. guess I haven't spent enough time under these cars :thepan:

danielscherbing
01-25-07, 09:30 AM
I agree with the exhaust comment. I recently upgraded my 02 Deville's exhaust by removing the resonator, replacing it and the entire exhaust system with 3 inch stainless and then switched the factory mufflers to Dynomax Super Turbos. Nice mellow sound and very little if not no interior resonance. Jump on the throttle and she screams! Just what the doctor ordered!

EcSTSatic
01-25-07, 11:41 AM
I agree with the exhaust comment. I recently upgraded my 02 Deville's exhaust by removing the resonator, replacing it and the entire exhaust system with 3 inch stainless and then switched the factory mufflers to Dynomax Super Turbos. Nice mellow sound and very little if not no interior resonance. Jump on the throttle and she screams! Just what the doctor ordered!

That is worth some pics here!

codewize
01-25-07, 08:57 PM
The resonators purpose is to lessen the noise. I think back in the day the purpose was to catch any sparks that may have come from the exhaust but now It's all about the nose reduction.

If you remove it you car will be louder. I don't see any reason why you would fail emissions because of it. As far as HP gain. Probably very minimal if any. The resonator isn't very restrictive.

Submariner409
01-26-07, 04:00 PM
FYI, did a tailpipe emissions test of my '02 STS before and after the CORSA install in November. No change in CO, CO2, NO, no codes, nothing. BUT, be careful when you pull the after-cat O2 sensor in order to cut the pipe to the first resonator/muffler.....don't kink the wires or twist them too much. Something about a "clean air reference signal".