engine work
The reason you loose HP is because you are basiclly screwing up the air flow. CAI pipes are smooth on the inside. The bypass is rough and has a valve in the air flow. A CAI is only realisticlly gonna give you another maybe 5 hp and most of that on the top RPM end, where you don't drive most of the time. The bypass is goning to screw the flow up through the entire RPM range.


