HaulinAsp said:
people tend to get impressed with the higher associated boost psi's generated by the diesel engine
Fact : Boost is a measurement of restriction.
:dontknow: :dontknow:
PROF! Please help me!
Where do people get this idea?
Boost is simply a measure of
manifold pressure. Manifold pressure greater than the ambient atmospheric pressure, obtained by supercharging or turbocharging. Boost is measured in psi, inches of mercury, or bar.
Restriction is an impedence of flow. A measurement obtained by calculating change of cfm, or the resulting drop in atmospheric pressure inside the manifold. during the intake stroke, or an increase in pressure measured in the exhaust during the exhaust stroke. Intake Restriction would cause a drop in pressure "boost" in the intake, because the only exit is through the exhaust valves which are closed. The restriction upstream from the boosting mechanism, which is open to the atmosphere, reduces flow and would effectivly reduce velocity and cfm of air entering the manifold, reducing the pressure "Boost".
The restriction on the exhaust side has a different effect on boost in this reference because the intake valves are closed, and the piston provides the mechanical energy to evacuate the cylinder, thereby isolating the manifold from which boost is measured. In restricted exhaust flow results in decreased velocity, thereby reducing the effectiveness of the turbo, reducing the boost as well.
CFM is not velicity, it is a measurement of the flow of a gas or liquid that indicates how much volume in cubic feet pass by a stationary point in one minute. The higher the CFM the better the suction. which is directly proportional to the pressure. As pressure drops, the effective CFM drops as well. As pressure increases the effective CFM increases as well.
HaulinAsp implies that increasing boost in an engine is the result of restriction.
I dissagree . I say that Increasing the boost which is measure in the intake manifold is the result of more air in the manifold. I say increasing restriction decreases the boost.
Who is right, and why?