vwbased wrote:I believe the vacuum pump maintains a constant pressure polarity across the ring package thereby preventing ring flutter. Without a vacuum pump, the pressure polarity cycles between more pressure on the chamber side (combustion and exhaust) to more pressure on the crankcase side (intake). As the ring "flutters" from one side of its ring groove to the other to follow the
pressure polarity, its leaks. Of course the inertia of the ring also plays a role in "flutter".
banjo wrote:I have a theory on why it builds hp in loose motors and nothing in tight motors. Could it be introducing vacuum into the crank case helps the engine in the intake stroke by increasing the vacuum in the cylinder. This in turn increases the amount of air/fuel mixture that gets into the cylinder. Maybe even sucks out a little residual exhaust. This would result in a cleaner charge in the cylinder and results in more cylinder pressure. In a sealed up motor nothing is getting by the rings so it doesn't help. What do you guys think, Is this reasonable?
Does nascar or prostock run vacuum pumps?
Also has anybody measured engine vacuum before and after the addition of a vacuum pump?