Quote Originally Posted by johnnyapollo View Post
I still don't know if the ECU compensates though. If the VX still feels sprightly to you where you live I'd say that it does adjust.
I'm no mechanical engineer, but I can't see how the ECU could compensate. The problem is a reduction in the amount of available oxygen and nothing the ECU could do can substantially increase that in a normally aspirated engine.

It could certainly make the fuel mixture less rich to match the reduction of oxygen - so no fuel goes unburnt. I think that would save gas, but would not increase power.

My understanding is that forced induction via a turbo or a supercharger is the only way to compensate for reduced air/oxygen pressure.