On an extended trip through the southwestern states, our 2004 Honda Odyssey seemed to get a few more miles per gallon when we were at higher altitudes than when we drove in the lower elevations. Was this a fluke? If it’s true, can the vehicle’s computer be set to give better fuel economy when we’re home?
Less air available at higher altitudes(due to thinness) means less fuel(aka better MPG) needed for programmed mixture which equates to less power. It is almost like you have a smaller engine at high altitudes.
Honda spent many hours of R&D to come up with a reliable “tune” for your engine for optimal power, reliability, longevity and fuel economy. Can it be done yes, for a few MPG hardly worth it.
Less air available at higher altitudes(due to thinness) means less fuel(aka better MPG) needed for programmed mixture which equates to less power. It is almost like you have a smaller engine at high altitudes.
Plus, your car is pushing through “thinner” air, offering less resistance. This is why jets fly at such high altitudes: less air resistance in thinner air = less fuel burn.
Your car is “smart” enough to always adjust fuel delivery to match available oxygen at any altitude. Trying to “lean out the mixture” beyond what your car is programmed to do may result in engine damage due to high combustion temps and/or detonation.
I will add one more. At higher altitude your engine requires lower octane fuel. If you are using a lower octane fuel, you might be able to raise your regular mileage by using a little higher octane fuel at lower altitudes.
that will just cost the OP more money. Mileage won’t improve with higher octane unless the engine’s designed to use higher octane.
What would work is to put a restrictor plate in the air intake. Less air coming in = less fuel added to the mix.
But that would also cut your available power, which could be dangerous in an emergency situation. Realistically, you could probably realize the same MPG increase by driving more conservatively.