Quote:
Originally Posted by titanic
Wow thanks, so it's the airflow that makes the difference. Now I understand why we mess with the intake and exhaust to squeeze more HP. But then again intake has nothing to do with pollution, why would Porsche put anything there to restrict airflow?  |
On the intake side, the main restriction is the air filter. It is essential to prevent dirt that would destroy the engine from reaching the engine. Noise can also be a factor, as can the physical space needed to make an ideal intake system.
In addition, air will flow differently through the system at different speeds. One intake manifold might be great for high air flows, but not great at low air speeds. Or vice versa. That's why the Cayman intake has two vacum actuated flap valves inside of it that are opened and closed at different RPMs. This allows the ECU to 'tune' the intake for best airflow at all air speeds.