Mad at new exhaust
#1
#5
#6
^^^what scott said. take the muffler off i would never put a muffler on a 6.7 with stock turbo. for the reason stated above. and you wont lose any torque if you loose the exhaust. the turbo will hold the same back pressure with or with out a muffler untill you go to a bigger turbo back pressure will not change.