[pacoluca]

I think maybe once you are used to driving in comfort mode, the moment you change it to eco pro, you are unconsciously stepping on accelerator paddle more to get the speed up to where you want, so it uses more fuel. it's just my theory.

[ovekvam]

Originally Posted by pacoluca

I think maybe once you are used to driving in comfort mode, the moment you change it to eco pro, you are unconsciously stepping on accelerator paddle more to get the speed up to where you want, so it uses more fuel. it's just my theory.

But isn't rather brisk acceleration good for consumption? Just like airplanes save money by burning a lot of fuel to get quickly up to high altitude, I think cars should get rather quickly (low RPM, high load, low pumping losses in engine) up to a pace where they can cruise economically in a high gear.

The key to low consumption is to not waste energy. Never brake if you don't have to. Coast as much as possible. Avoid high speed where too much power is used to overcome aero drag. Avoid low speed where you can't use high gears.

[BenArcher]

Just to add a bit more info.

I played around with the coasting a bit today and it seems that at 80Km/h my car thinks it is using 1L/100Km.

Which would lead to the assumption that at idle the engine uses around 0.8L per hour. I still have no idea if it actually saves fuel.

[orcomma]

Originally Posted by ovekvam

But isn't rather brisk acceleration good for consumption? Just like airplanes save money by burning a lot of fuel to get quickly up to high altitude, I think cars should get rather quickly (low RPM, high load, low pumping losses in engine) up to a pace where they can cruise economically in a high gear.

The key to low consumption is to not waste energy. Never brake if you don't have to. Coast as much as possible. Avoid high speed where too much power is used to overcome aero drag. Avoid low speed where you can't use high gears.

Exactly! And accelerate before a hill so you can let the car slow down a bit on the upward slope - saves fuel and you average the same speed.

[ovekvam]

Originally Posted by orcomma

Exactly! And accelerate before a hill so you can let the car slow down a bit on the upward slope - saves fuel and you average the same speed.

Yes. And the cruise control is not very good at this. In hilly areas, it tends to do the opposite. It accelerates over the crest, and brakes just before the road levels out after the downhill part.