If there’s one thing as a motorist that really cheers me up with the arrival of the warmer months, it’s seeing the water temperature gauge moving off its stop a lot sooner after a cold start-up than in the winter. Of course that means getting more energy out of every gallon of fuel, a quicker cabin warm-up on cool mornings, and our engines even seem more enthusiastic about work. Warmer weather also means tyres that give you more grip, run quieter, and use less fuel, as they heat up more quickly. These various benefits also come around the same time that we probably see the last tankfuls of winter diesel that we’ve been running on since November. It’s not the best stuff for fuel economy, as it actually has less energy per gallon/litre than summer grade diesel, and this change, along with all the previously mentioned factors, generally brings about a visible boost in mpg figures. If your month-to-month motoring pattern remains mostly unchanged, and you keep your fuel buying figures on record, the changes will usually be immediately noticeable.
I could not help but notice though, digging back into my own fuel records and going back over 18 years. They covered seven cars, all with different engines, and I found the difference between winter average mpg figures and summer statistics seems to have noticeably changed – mostly for the better. The drop experienced in winter now seems significantly less that it was a decade or more ago, and I suspect this is probably down to the measures that the manufacturers have taken in engine design for quicker engine warm up. That improves fuel economy, but significantly also reduces cold engine emissions – one of the main reasons for action being to meet Euro-5 and -6 regulations.
Digging deeper into my copious fuel records was also an eye-opener in terms of the cars’ overall mpg figures though. My two fairly recent bulky Peugeot 3008s, both using that rather excellent 1.6 HDi engine, almost exactly matched the 55mpg fuel economy of a significantly lighter and smaller Audi A2 1.4 TDI 90 of nearly 15 years earlier! Mind you, I don’t think that I had really discovered economy driving when I had the Audi A2, and with 0-60mph in 10.6 seconds (pretty quick in those days) and 90bhp in a car that weighed only 1,030kg, the A2 wasn’t really a car to drive too slowly. I am quite sure that it had 65mpg plus potential, as I can see in the records two summer tankfuls when I hit 61.5mpg without even trying. The aluminium unitary bodied A2 had a small frontal area and fine aerodynamics, with a top speed of 118mph from just 89bhp, when today’s comparable SEAT Ibiza 1.6 TDI 95 only manages 113mph from 5bhp more. But the comparison makes those regular 55mpg averages from the 3008s look really good though, and I knew that on a friendly road I could get 60mpg plus without too much effort from them both. Why can’t you guys and gals with long-term cars do better? I can’t remember when I last saw any 60mpg plus “on test” figures!
Now is the right time though to get out there and put your eco driving skills into effect, with the better weather, and before the roads get too busy with holiday traffic. Fuel certainly isn’t getting any cheaper, and if Donald Trump falls out with Iran, with their crude oil output already down 30 per cent on last year, diesel prices are set to keep climbing globally as supply dwindles. I’ve heard recently from a reader who has clocked a very first 70mpg plus run, and it shows what you can do with a bit of effort, and without getting in anybody’s way. Cars behind may sometimes tailgate you, possibly making you think that you are being an obstruction, but remember that some people always drive that way, whatever the speed of the car in front, and you’re often doing them a favour by saving them some fuel anyway!