Can't Get Good Fuel Economy - 2008 Civic Manual

[Christ]

Early shifting still works to an extent, since even in Vtec mode, the higher you rev, the more fuel units per minute you're using.

If your a/f ratio is a constant 13:1, and you're revving 2000 RPM with an engine that has 1.0 liters displacement, vs revving 1000 rpm with the same displacement (not counting volumetric efficiency, as this is just an example), you're using 2x the fuel per minute.

The difference comes with gearing. Are you using more or less fuel per distance?

[NeilBlanchard]

Right, a lot of us have engines with variable valve systems - my xA has a VVTi 1.5L, which is essentially the same thing. The idea is to broaden the power band -- at lower RPM's fewer valves are actually better, and at higher RPM's more valves are used to improve power. So, the engine can have better efficiency at lower RPM's than it could w/o the VTEC.

All ecodriving techniques still apply.

[KJSatz]

Hmm any progress?

I think my next tank will be lower, but there's more city driving, and it's been colder. Today's nice though.