Cobb AP Question

[finse]

Does anyone know how to log manifold pressure with the Cobb AP (ver 2)?

[aftCG]

Boost? Even negative numbers (vacuum) are technically atmospheric pressure trying to ram itself into the manifold.

 

That's the way we think of it in aircraft engines anyway.

[BAC5.2]

Just go to to the "log" menu and push OK. It should log manifold pressure along with everything else.

 

Vacuum is not atmospheric pressure trying to ram itself into the manifold.

 

An engine is an air pump. Think of a wet-dry vac. Turn it on, and there is a pressure differential created because air is evacuated faster than it is sucked in, that's how it picks up spilled rice or whatever. If you take the hose of the vacuum and put your hand over it, you create an even larger pressure differential in the can. The motor is trying to process air, and you are restricting inlet flow. In the case of a car, the throttle plate acts like your hand over the vacuum hose. Open the throttle, remove your hand, and you decrease the pressure differential and increase efficiency.