Yes backpressure doesn't start from the catback, but the catback is part of the cause to backpressure. It all depends on the car your working with you can add headers,tp, a catback+tune like on a civic and won't see much gain. The statement that you can only see 5-6whp and just for sound on a catback is not true. For example some turbo'd cars see around 15+whp w/o tune. I think the new Z can probably put down more then 5-6whp with a catback+tune.
|