robert@bisimoto
13-11-2009, 11:30 AM
The header can produce substantial amounts of power on a motor with very few negative compromises. They are a rare, win-win mod, with hardly any trade offs.
Heads make more power by primarily using resonance tuning to create a low pressure, reflected wave, rarefaction (vacuum) pulse during the overlap period. The overlap period is in between the end of the exhaust stroke and the beginning of the intake stroke, where both the intake and exhaust valves are open at the same time for a few degrees of crank rotation.
On a header each individual exhaust port is treated to is own separate primary runner instead of merely dumping into the shared main pipe fo a log manifold. That is why is it better to use a real tubular header over a cast iron Honda manifold.
Heads make more power by primarily using resonance tuning to create a low pressure, reflected wave, rarefaction (vacuum) pulse during the overlap period. The overlap period is in between the end of the exhaust stroke and the beginning of the intake stroke, where both the intake and exhaust valves are open at the same time for a few degrees of crank rotation.
On a header each individual exhaust port is treated to is own separate primary runner instead of merely dumping into the shared main pipe fo a log manifold. That is why is it better to use a real tubular header over a cast iron Honda manifold.