But let’s first examine exactly what we have here, which is a car that, in basic form, weighs 10kg less than two tonnes. With all the equipment that’s been shovelled into this one, I’d expect its actual mass would be closer to 2.2 tonnes. It’s powered by a 3.0-litre engine pushing out over 100bhp per litre – 316bhp to be precise – and just a fraction more than 500lb ft.
All this is enough to accelerate this colossus to 62mph in 5.4sec; if you wanted to accelerate that fast when I first got into the business, you’d need not just a Ferrari but the flagship model at that. So how much fuel would it use? To help me guess, I looked back at some of the old long-termers to pass this way, not least because some also had 3.0-litre diesel motors and all were driven in approximately the same way on the same roads.
First came the Audi A6 Allroad I ran five years ago. It had a little less power and torque than the 740Ld and was around 90kg lighter, and it did 38.8mpg in my hands, which I considered “impressively economical”.
Then came the Mercedes-Benz CLS 350 CDI Shooting Brake I had in 2014. It weighed the same as the Audi but had a lot less power and torque. Yet it did just 38.9mpg.
And then, of course, there was the old 730Ld, the previous model that I’d run on the Autocar fleet back in 2010. It was nowhere compared with this 740Ld in terms of either power or torque, but it was a substantial 125kg lighter. Its fuel consumption during my time with it was 35.8mpg.
So what would you think the new 740Ld would do with all that extra power, torque and weight? I bet you’d not think it would be over 10mpg better than the old 730Ld and neither did I. But it is: 46.3mpg over the first 2500 miles of its time with me. And no, that’s not taken from the trip computer, but calculated from miles covered and litres added and averaged out over every tankful. Not that there have been many of those.
Another thing I absolutely love about this car is its range. I consider a family car that can’t cover 400 miles between fills as not fit for purpose in this regard. I think 500 is pretty good and 600 exceptional. But the 740Ld managed to put more than 800 miles under its wheels between its first and second fills in my hands, which I regard as little less than staggering.
Indeed, the only thing that annoys me is that despite the car’s phenomenal frugality, the computer still elects to lie to me how much diesel it’s consumed – which, if you allowed yourself to be taken in by it, you’d think was better than 50mpg. It’s good, but it’s not that good. I don’t believe BMW is unable to measure more accurately, so this irritating optimism seems to me to be engineered in.
True, there are many other manufacturers that are no better, but to me that’s no excuse. Otherwise, life with the big BMW is proving as easy and relaxing as any real customer would hope and expect. It is such a capable luxury car that you’d think BMW had been building them like this for years when, in fact, this is the very first 7 Series that deserves to be considered a proper and serious rival for the Mercedes S-Class.
And I’m not alone in thinking that, as a letter from a reader who’s just bought a 740Ld after a series of big Benzs makes clear. More from him next time.
FUEL CONSUMPTION Show me a big hybrid that’ll do over 45mpg on a long run and I’ll start to think that diesel has run its course. Until then, it should have a future.