V6 MPG

[k_f]

Filled up my V6 auto with fuel this week. 3 weeks ago I had filled up with BP Ultimate (super) unleaded and the low fuel light finally came on after 465 miles. I drive smoothly but not slow like an old lady. The trip computer said 34.9 mpg and working out the mpg from the fuel figures (70 litre tank, 10 litres left when low fuel light comes on) gives the same figure. Although there were about 300 miles of motorway driving in there going as high as 70mph (true speed), some of it involved back road driving and short runs locally. I know this figure will be less than many diesels but it kills the myth that big petrol engines are always gas guzzlers. Historically my brim-brim mpg figures vary between 30 and 35 mpg.

[mjb]

Not bad. I've done 707 miles (Bremen, Germany to Stoke, UK) comfortably on a single tank of v-power in a V6 coupé with every inch of space occupied by people or luggage. The fuel consumption difference between 60mph and 70mph is considerable - that's where wind resistance really starts to push back - so I rarely drive at 70mph. I either relax behind a truck, or go flat out (only when in Germany on unrestricted motorways of course...)

The difference in economy between petrols and diesels is quite substantial at 130kph on the GPS (80mph) - a few months ago we compared my BMW and the wife's HDi90 at that speed while driving in convoy across Europe. I got under 30mpg, she was still getting about 60mpg!

Sod it I'm procrastinating so let's go through what motorway economy I've gotten from various cars I've owned recently (same Stoke-Manchester route, same time of day, 56mph slipstreaming trucks in dry weather): V6/V8 run on Shell V-Power, the tubby ran BP standard unleaded, the diesels Shell standard devil fuel.

406 2.0 Turbo: 34mpg
BMW 540i 4.4V8: 38mpg
VW Golf Mk.4 2.0 TDi: 45mpg
406 3.0 V6: 49mpg
406 HDi90: >60mpg

Yep, the V6 was more economical on a run than the diesel Golf, which would give me 45mpg whether I was doing 50mph or 80mph (at which point it'd go into limp-home, killing the turbo, and STILL only give 45mpg) In fact, when you consider the price of diesel, the V6 was almost as cost-efficient as a HDi at those speeds!

For humorous comparison, here's my average economy for my run to my current workplace (5 miles, very start-stop with a hill sprint at the end):

406 2.0 Turbo: 17mpg
BMW 540i 4.4V8: 20mpg
406 3.0 V6: 23mpg
VW Golf Mk.4 2.0 TDi: 25mpg
406 HDi90: ~30mpg. Not done many runs in this

Interesting how in every case the economy is almost exactly halved... The HDi belongs to the missus, who does mostly short urban drives but still gets the trip computer to average out at something daft like 48mpg. Bloody boring though, plus it stinks, and sounds like a tractor