For those of you have the magnaflow hi-flo cat (or others who know), does the CEL turn on when this was installed, can you feel horsepower gains and how much louder does it make your car?

 

nobody knows?

 

It shouldn't unless you also have a header and thus removed your 1st cat as well. The o2 sensor is before the filter element on both cats, so as long as the 1st one is in place, the 2nd one will get a different reading (correct me someone if I'm wrong).

 

i dunno.. but i can run mine for a while w/o the CEL comming on.. and thats with both removed... the only time it comes on is when I run under heavy boost.. and my fuel is runnin pig rich.. then my mas is like whoa ... overload....*Turns on CEL*