OBJECTIVE: Wet flow, pressure excursions, port volume, runner length, plenum volume—all these figure into an engine's overall efficiency. But there's more… Sometimes theory is neat, but ...

The volumetric efficiency table is probably the most important one in any ECU.The vertical axis is engine load, in this case, ...

Fuel consumption, however, does not follow the same curve as the manifold pressure. Full retard results in the most fuel consumption and full advance appears to have the least fuel consumption.

The manifold absolute pressure sensor reads the amount of pressure or vacuum (also called “engine load”) in the intake manifold, where outside air is divvied up in proper amounts and ...