Originally Posted by xlite
Removing the cover buys a reliable 1-2mph but removing the foam after that does nothing. For some reason with the new SBP pipe my motor bogs with just the foam (pic) but runs great with foam&cover installed or no foam&cover at all.
Apparently tuned pipes need tuned intakes.
A tuned intake is incredibly important on a piston port motor. It uses the inertia of air to act as a valve.