I have a 2002 monte carlo ss and Im thinking of cutting off the resonator and just ending the pipe after the u-bend because my flowmaster 40s dont seem loud enough... I cut a slit in my resonator and I loved how it sounded except for the exhaust gases hitting the cut pipe but my mom was driving my car at the time and she couldnt stand it so i got it welded back the next day but i plan on cutting a large portion of the resonator so it wont have the leaking type noise... Will this affect my gas milage or the O2 sensor or throw a CEL? Ive read various forums saying that the engine needs back pressure but some people were saying that was a myth.

 

As long as you cut after the second O2 sensor, there will be no code thrown. However depending on the kind of cut you do to the exhaust, you could lose back pressure which will lower torque at low rpm's.

Gas mileage probably won't be effected much at all (+-1mpg).

 

I didnt know there was a certain way to cut it lol. What kind of cut do you recommend? When I did it before I did notice that when I floored it there was no longer a seat wreching thrust like it did before... A few days after I got it welded back I did get that "neck breaking" thrust back again lol (I rarely floor it )

 

The only reason I said that it depends on how you cut it is because you mentioned that you were going to cut a portion off of your res.

What I would recommend is that you consider what your goals are. If you plan to continue modifying your Monte, feel free to remove the res. If this is all you're going to do, then just remember that you will lose some bottom end power due to the lack of a res.

 

Ive been deleted my resonator and had straight pipe for a couple of months now and I cant really remember if I felt any loss of power or not... (horrible memory) And sometime in the future (whenever my budget allows me to) I will continue to mod my Monte piece by piece...