Despite generally not being too fussed about my mpg, after recent talk of whether a 335d was capable of achieving 50mpg 'on a run', I thought I'd investigate. I've previously had more than 50mpg twice but didn't think I'd need evidence of such to 'prove it' and I've since adjusted my OBC accuracy (reduced by 4%) to match 'brim to brim' calculations.
I've tried to note as many potentially influential factors as possible (and a few trivial facts!), but please feel free to ask if there is anything I've missed.
Date: Saturday 12th April 2014.
Car: 335d saloon.
Mileage: 1322, barely run-in but glad it has!
Wheels: 19" (403 style).
Tyres: Goodyear Eagle 1 Run-Flats.
Tyre pressures: not checked but they were as recommend by the sticker when measured two weeks earlier.
Weather: 12c, light winds, dry, mostly overcast.
Cargo: 5 people (wife, our 2 teenage children, son's girlfriend, myself) plus approximately 10kg of luggage in the boot.
Estimated cargo weight: 320kg.
Fuel type: bog-standard diesel (approximately 75% Esso at a very reasonable 131.9p/l) and 25% Asda at 132.7p/l).
Fuel carried at start of journey: 3/4 of a tank (approximately 43 litres).
Engine temperature at start of journey: cold.
Auto-start/stop: on (not active for immediate local roads (cold engine), activated a couple of times during roadworks).
Driving mode: 'Comfort' for the entire journey.
Driving style: around 1/3 throttle to get up to speed which is reasonably cautious but still felt spritely in a 335d and in any case, I wasn't going to drive like a stereotypical BMW driver with my wife and kids on board.
Potentially fuel sapping functions: automatic air-con - on, front/rear heated seats - off, cruise control used.
Purpose of journey: meeting Mom and step-Dad for a pub lunch (a genuine 'real world' medium length journey for me).
Journey details:
Local 30mph roads from my home near Lickey Hills, Worcestershire (couple of short stops at junctions, approximately 25mph average);
M42 J1 to J3A (virtually no HGVs but still fairly busy with weekend drivers so averaged around 65mph);
M40 to J16 (used cruise control set to 78mph);
A46 to A45 (used cruise control set to 75mph);
A45 (heavy traffic due to roadworks so 25mph for the first mile but then average was around 55mph);
B4455 and then A428 in to Church Lawford (single carriageway at national speed limit - some straights at 65mph and a few bends at 45mph, stuck at 25mph behind a tractor and a few cars for a minute);
No delays in parking - reversed straight in to a spot.
Lamb chops and a pint for lunch.
The return journey was similar but the A45 traffic was a little heavier and I hit 80 on the M40 a couple of times, so the consumption was 2.6mpg less. An average of
51.5mpg over the 77 miles.
I suppose I could have waited until my engine had worn in a few thousand miles
and selected Eco Pro
and started with a warm engine
and turned the air con off
and had less or no passengers
and sat behind lorries doing 55mph
and avoided cruise control
and carried less fuel
and used premium diesel as that would have increased the fuel efficiency (I suspect to above 55mpg), but it would have detracted from my own 'real world' 'on a run' journey.
I wouldn't dare to argue that 50+mpg is a regular occurrence in a 335d. Even with fairly common 40+mpg (plus a couple of 50+mpg) journeys, my wife's 11 mile cold start commutes at 34mpg (improving at little with the warmer weather) and some of my post run-in performance experiments, have tempered our average to 37mpg. Still happy with that for a 300+hp machine. The fact remains that a 335d is easily capable of 50+mpg 'on a run' and not necessarily in ideal conditions.
Guys, I know some of you have been sceptical and yes, if the car is driven spiritedly, of course there is no chance of getting 40 to 50mpg; it's not rocket science! However, in the real world I have a good mix of driving which doesn't always include 'flooring it'. I know there will be some drivers who state their 335d never does 50mpg but there is little I can do about that and provided we all enjoy driving our 335d's it shouldn't matter. I also suspect there will some non-335d owners who remain sceptical (semantics over what 'on a run' means?
), but I'm not sure why I should care anyway!
After all it's
my fuel money I'm spending.
I hope this has been of some interest to you. I was asked and now I've delivered.
