Manual selection + Sport mode = Better fuel economy??

[Spinflight]

I'm still getting to know Pandora, only have a thousand miles or so in her but had a trip down West to Pembrokeshire this evening so had a play around with a few things.

Slipped her into Sport mode when I thought the Missus wasn't watching and flipped the gearbox to the left.

To my surprise she reported that the ride improved considerably ( think one of the rear rims is a bit mishapen and have a new one coming). Handling seemed to improve noticeably, felt like she was on rails. The car that is not the missus. Everything felt smoother.

Three hours later I checked the trip stats and found the fuel economy was considerably better than I'd seen previously. About 5mpg better. This comparing good fast 60mph A roads to similar or motorway use previously, where I'd made a lot of use of the cruise control. Which is a bit confusing for me... How is my leaden foot with quite a smattering of roundabouts more efficient fuel wise than constant speed on the motorway?

So I've seen a 'From the Garage' episode which goes into how to drive the J gate etc, is it normal to get better fuel economy from such? And is there any actual documentation on how all this works?

[mike020150]

It sounds like the car is responding well to being used regularly, perhaps after a period of inactivity? It sounds like you have given the car an 'Italian tune-up'.
Using the sport mode moves the gearbox change points higher in the rev range and the car will use more, rather than less fuel. The single biggest affect on fuel consumption for any typical journey is whether that journey incorporated a cold start and how quickly the mechanicals reached working temperature after starting (at least 10 miles, often longer). Even a restart after 2/3 hours won't take as much fuel as a genuine cold start after overnight parking. With large engines in particular, a cold start is like throwing in buckets of fuel. Typically, a hard driven XKR will struggle to reach 20mpg whereas most sympathetic drivers can return mid twenties or more on a decent run. Mike.