the local dyno shop i go to has this new exaust setup to muffle the noise and exaust out the fumes.(they are two semi exaust mufflers) i have dynoed on here before the exaust setup,and it seemed that i can pull up to 9000 rpm np.now with this new exaust setup he has, it feels like a lag dog cant pull up to 9000 rpm.but on the highway i can.should i be dynoing with this exaust hooked up?

 

anyone?