Variable Valve Timing and Fuel Economy

[HustleRussell]

My old BMW 525i is doing bang on 3,000RPM at 70mph.

Above 3,000RPM, VANOS starts to advance the inlet valve timing.

Now, I've been driving at 70mph in the belief that the engine will be more economical with the retarded valve timing.

I'm wrong, aren't I?

I have always noticed that this car seems to be less economical when I try to drive it economically (keeping engine speed down by using higher gears / larger throttle openings).

[HustleRussell]

Some interesting stuff here but it doesn't really answer my specific question which is will the engine be operating more efficiently off VANOS or on it? Peak torque is up at 4,200RPM which suggests to me the engine would be more efficient after. VANOS has advanced the inlet cam timing.

I'm not a hypermiler, you won't see me coasting in neutral or labouring the engine at below 1,500RPM any time soon.