Derrick Redd

I picked up 7 RWH NA on the dyno with the cutout open.

Antz97ZNJ

w/ the mods you have now id say somewhere around 5 hp between the corsa or open w/ the cutout

BlownF1

It all depends on the vehicle and the mods, horsepower level you're making, etc...in my case (500+rwhp), the car picked up 15rwhp on the dyno going from closed to open. It's really about how efficient the whole system is to begin with...some cars will see huge gains, others very little. Sounds cool though...