Mazda RX8 Stock Intake- information correction

[@tominator7728]

Thanks! I have my stock intake. Never had my bumper cover off of mine, so I hadn’t seen this before.

[@jamesowen418]

It's the VFAD (Variable Fresh Air Duct), really for keeping intake noise down on the stock car. But you can see it's essentially a cold air feed into the stock airbox. Mazda did a lot of R&D and got a lot 100% right on the stock RX8 👍🏻

[@pv4083]

Thanks for the info!

[@rotaryperfection]

Um no! That duck has nothing to do with noise. It's purpose is to change the runner length of the entire intake system. When vacuum is applied at low rpms, the air has to travel the full length of the duck. Adding length to an NA intake moves the torque peak down in the rpms to give you better bottom end torque because the added length allows the air to have more momentum in the tube. At higher rpm's that added momentum can now become a flow restriction when the air reaches a certain CFM so Mazda designed the duct to open shorten the distance the air now has to reach the airbox to help with flow in the top end. If you really think about it, the fresh air duch does the exact same job as the primary and secondary runners but pre-throttle body. The primary runners are long to move the torque curve down and then when the secondaries open, the runners are shorter in length so the torque curve moves higher up. The fresh air duck is doing the exact same thing just pre-throttle body (long in the low rpms and short higher up). It's all designed to work in harmony.

[@pv4083]

@@rotaryperfection beautiful, thank you for the information brother

[@kuriakoskast]

Long intake good for low rpm short intake good for high rpm!!!

[@pv4083]

Thanks