i have a 09 gmc sierra that has a 5.3L v8 engine pushing 315bhp. i have installed true duel exhaust with 2.5 inch pipes. i have not changed the headers and there is a catalytic converter on each pipe. my question is what would be the horsepower and torque increase from adding the exhaust system?
fyi. i have no mufflers it is straight pipe
fyi. i have no mufflers it is straight pipe