Jun 11, 2008

Save Gas

Posted in Science at 1:00 pm by David Bradley -- 15 Comments; add your comment

Apologies if, like me, you’re a Brit and prefer to refer to petrol and diesel, then apologies for today’s post title. But, I’ve noticed a flurry of complaints from Americans about the price of vehicle fuel, recently, and just had to comment. Complaints about the price of gas? I hear the good folks of England, Wales, Scotland, and Northern Ireland exclaim! Yes, indeed, apparently, filling your tank Stateside now costs a staggering $4 per gallon (about 8 pounds sterling!) Pah! You say, us Brits are paying the equivalent of over $10 per gallon these days.

So what’s a driver to do? Save fuel that’s what! But, how? Money-saving expert and pragmatic tide-wad Martin Lewis has a few pointers on his MoneySavingExpert site. In fact, he reckons following his advice could cut your fuel spend by a third and it doesn’t involve overthrowing a government with a penchant for heavy stealth taxes.

There are four key steps to saving money on fuel, Lewis explains:

• Boost vehicle efficiency
• Drive more efficiently
• Find cheaper fuel
• Get cashback on your fuel

The first of these involves removing any dead weight from your vehicle, detachable seats that never see a derriere could be stored offline, as it were. Roofracks and cycle racks should be taken down unless in use, and any trash, garbage, waste, rubbish lying in footwells, in the boot and trunk and elsewhere should be disposed of or recycled. Lewis reckons decluttering can save a couple of a percent, while ditching the roofrack and do the same.

Other fuel savers include keeping tires at the correct pressure for your vehicle (up to 3% saving), keeping air-con use to a minimum (A/C uses between 4 and 8% of your fuel in hot weather). Lewis’ final efficiency tip is slightly less obvious and possibly doubtful – don’t fill your tank, he says. A car will run just as well on a half-full (half-empty) tank as a full one, apparently. He claims that the weight saving of not filling up every time you drive on to a garage forecourt (filling station), will boost efficiency by about 1%.

I’m not so sure that this stacks up overall, however, because you will end up making twice as many journeys to the filling station, which itself will use fuel not only with the drive, but the stops and starts, and if you get stuck in traffic it could soon counteract that 1% saving. Especially given that being parked with
the
engine idling
for 5 minutes
is the
equivalent of driving
5 milesparked with the engine idling for 5 minutes is the equivalent of driving 5 miles, or thereabouts.

Anyway, back to his list. Lewis next suggests that being a gentler driver, rather than a kid-racer can save you up to 60% fuel without cutting your top speed. It’s not about the theoretically optimal approach of accelerating gently up to 56 mph and then releasing the accelerator pedal and cruising back down to close to zero and then slowly accelerating up to 56 again. Rather, Lewis explains, you should ensure you’re driving in the appropriate gear (for stick shift drivers only) and that you should speed up smoothly.

“When you press harder on the pedal more fuel flows, but you could get to the same speed using much less power,” he says, “a good rule is to stay under 3,000 revs [revolutions per minute, rpm].” Conversely, when you want to slow down, use the engine and ease down through the gears, reduce the need to stamp on the breaks. All that hard stopping and starting many drivers do simply wastes fuel. As my driving instructor told me at the start of my first lesson in decades past, “We’re all trying to get from A to B, but there’s no need to rush, be polite to other road users, and enjoy the ride.” (A good life philosophy in general, I thought).

Lewis’ Point 3 means either doing some legwork and hunting down the best buys for fuel or using one of the many price comparison tools on the web. In the UK, we have the aptly and simply named petrolprices.com. Lifehacker recently highlighted GasBuddy and Gaspricewatch in the US. However, if you find a filling station 30 miles off your regular route that offers a fractional per gallon saving, then give it a miss, the extra 60 miles will most likely counteract the saving. In tip #4, Lewis suggests cashing in on loyalty cards, cashback credit cards, and company savings schemes, which could save a few quid (bucks) too.

There are several other tips we might add to Lewis’ list. If you’re in the UK, agricultural vehicles avoid a certain amount of tax on their fuel, so becoming a farmer could save you money (and, of course, lose you it in other ways). You might be tempted to throw some magic potion, magnets or shiny beads into your tank in the hope of saving a few pennies. Don’t be. From a chemist’s perspective, I’d like to emphasise that drivers should avoid all such scams including so-called catalysts, magnetic gizmos, and shiny beads. Crystals, Reiki, and homeopathic remedies don’t work to fix human bodies, equally they are not going to let you squeeze extra juice from your car.

Some observers suggest switching to compressed gas vehicles, hybrids, electric, and fuel cells etc. These are all well and good, although on the whole simply displace pollution elsewhere in terms of the fuels they use. However, the enormous overall energy and financial cost of replacing even an old car is far, far greater even than maintaining an old banger (lemon).

Finally, here is the killer tip on how to save money on gas – walk or use a bicycle. Aside from the costs of extra carbs you’ll need to sustain you for the journey and the marginal increase in laundry costs for your Lycra cycling shorts, the broader outlook is for an almost 100% fuel saving. Of course, if you commute fifty miles a day, you’re going to have to set the early morning alarm just a little bit earlier to arrive at work on time, but just think of all those poor suckers paying $10 a gallon and listen to the dawn chorus and you’ll feel a whole lot better.