[Formulajones]

Originally Posted by Tim Corcoran

On that video he talked a lot about exhaust scavenging but least out an important aspect of it, specifically how the exhaust gas during overlap will actually pull in the intake charge during overlap. This is how a naturally aspirated engine can exceed 100% VE

Ive mentioned this before. Pulling in the intake charge during the exhaust stroke also has the affect of cooling the next cycle, the compression stroke. This helps ward off detonation. The more you advance the camshaft the more the intake valve is open at TDC on the exhaust cycle. Paul C explained it to me that he likes to see the intake valve open around .030-.040" at TDC on the exhaust stroke. This isnt always doable depending on the cam LSA. Wider LSA makes this harder to accomplish. On wide 112-114 LSA cams I can usually reach about .020-.025"