Originally Posted by charles charlie
Possibly a couple of factors.
Colder air is denser so means more fuel to maintain the AFR.
Also your y-pipe may be allowing better gas flow out which in turn means more air into engine. Again ECU may adjust fuelling to maintain AFR.
Or maybe you should just drive the thing and stop looking at the MPG?!
thanks was half looking for a scientific explanation….
So using “man logic” getting a Cobb or the Laptop driven EcuTek software would help (as would a custom map) ???
And enjoy the new noise and use the loud more