[Christ]

Originally Posted by worstmechanic

But, if the engine control system DOES work as I described, an MAFS that is reading incorrectly shouldn't affect how rich or lean the mixture is. At steady state, the feedback from the O2 sensors should compensate by generating a new fuel/air inlet target, which will, in turn, get everything back to normal.

As far as the test proposed in the previous post, I don't think it will prove anything if the electronic engine control DOES work as I suggested. If you increase the air flow, the MAFS will see it. Since the feedforward control maintains a air/fuel target, the fuel flow will be increased. It will run faster.

Assuming the same engine control system, here's something interesting that should happen. Say you're driving down the road at a steady 60 mph. Your goal is to maintain that 60 mph. Now, let's say I have a genie remove the air filter completely as you're driving. The MAFS sees a higher air flow. The engine control system sees the higher flow, and since it's trying to control the air/fuel ratio at its current target, it increases the fuel flow. (No, you haven't pressed the gas pedal down any more.) As a result of the inrease of air and fuel, your vehicle speeds up. Since your goal is to maintain 60 mph, you lift your foot off the gas pedal a little (which closes the throttle butterfly a little). Air flow decreases, which causes the fuel to decrease. Eventually, you're back at 60 mph, using the same amount of air, and same amount of fuel. The only difference is that you are at a lower throttle position. In other words, the restriction in the air flow has just moved from the air filter to the throttle plate.

I'm sorry, I think I have to tell you that your nick is accurate at this point.

Under vacuum, higher flow doesn't occur until the engine requires it to. Period.

It doesn't matter if you change the filter, or just remove it altogeher. There is no more flow at 50% throttle with a K&N than there would be at 50% throttle with a paper filter, or no filter at all. That's just how it works.

The largest restriction in an air throttled engine is, and always has been, the throttle plate. As long as whatever blockage is before the throttle plate has less restriction than the throttle plate itself for a given throttle setting, there is no more or less airflow than the engine would have under the same throttle setting with a completely open intake tract.