why do you not want to let your dad know? father's day present ar? oh wait its over. ok serious, if you dun wan to let your dad know you supercharged the rolla, it is near imposible unless you caught a leprecon. because the most stealthy supercharger is probably the centrifugal setup, where it is posible to run without that intercooler, and centrifugal blower cost a bomb. root type on the other hand might left your dad wonder why is there 2 extra bulky thingy in the engine bay, you're not going to tell him its used to save fuel don'cha?
even if you can hide from him you might have to deal with your dad thinking a bearing kong somewhere in the car cuz its whining all the way when driven on the road and send it to the mech.