February 4, 2013
Article and photos by Justin Pritchard
Do you measure your fuel consumption at every fill-up? Or just glance occasionally at the computer readout that indicates how many litres per 100 kilometres (or miles per gallon) of gas your engine sucked out of its current tank?
The driver computer display is often off – sometimes by over 15 percent. I drive different cars every week. Some are accurate. Some, not so much.
Solution? Measure your consumption by hand. It’s easy and fun (okay, I think it’s fun). After your next fill-up, stop pumping when the pump clicks off. Over-fueling is bad for your vehicle’s emissions system anyhow. Then, after paying for your fuel, return to the car and reset the ‘trip’ meter to zero.
From this point on, you need two numbers next time you visit the gas station. The first is on the gas pump. It’s the number of litres you feed your ride. Take the decimal point out, and round to four digits. Save that number. Second number? The number on your trip meter.
In action? You put 47.221 litres of premium unleaded into your WRX, and the trip meter says 483.2 kilometres.
Bust open your Smartphone’s calculator app (or your calculator watch from the 80s), and punch in “4722 / 483.2”
Congratulations! You’ve just achieved 9.8 L/100km. Reset the trip meter and start again on your next tank.
Most Canadian drivers don’t track their fuel mileage, but it’s a great practice for several reasons. Key among them are the fact that: 1) it can reveal a practice that’s costing (or saving) you money, and 2) it may reveal a steady increase in consumption that represents a problem.
If you track your mileage, you’ll also notice that, in winter months, your vehicle uses more gas. Maybe 5 or 10 percent more than usual. Maybe more. And especially if you have a remote start system, winter tires, and a ski-rack clamped to the roof.
Cold air is denser, meaning your vehicle needs more fuel to move through it. Plus, you’ll use electrical accessories like the heater and the lights more often – all of which raise consumption. Add in the extra weight of snow and slush-goblins stuck beneath your ride (and their negative effect on aerodynamics), and it’s easy to see why consumption spikes when temperatures drop.
Thankfully, some easy maintenance tips can help combat these negative effects. And, as an added bonus, they can increase the peace of mind that comes from knowing your ride is in top-notch shape for winter driving – and won’t likely crap out on the side of the highway when it’s 37 below.
Cooling System: Ensuring your fluid, hoses, rad, water pump and thermostat are in tip-top shape won’t give you an extra three miles per gallon, but it could prevent your engine block from freezing and cracking, which would suck. Also, a healthy cooling system will help your vehicle’s cabin warm up faster.
Your favorite mechanic can inspect the condition of your cooling system in an hour or so. Maybe a bit faster if you bring him a Timmies. Remember: a properly functioning cooling system allows your engine to reach its operating temperature, and achieve optimal fuel mileage, more quickly.
Tire Pressure:An improperly inflated tire wastes your cash faster than that high-maintenance girlfriend you didn’t want your mom to meet. Without a precise amount of pressure inside them, a set of tires will burn more gas and wear out more quickly. They’re also a safety concern.
Thankfully, checking and adjusting tire pressures is one of the easiest and least expensive maintenance tasks your ride requires. Time required? About 90 seconds. Cost involved? About three bucks for a half-decent tire pressure gauge. Check the pressure of your winter tires regularly to maintain good fuel mileage and tire-life. This is especially important when temperatures fluctuate wildly in transition months like December and March.
And remember—check pressures when the vehicle has been parked a while, and regardless of whether you have a Tire Pressure Monitoring system (TPMS) or not.
Air Filter: Don’t forget your air filter. Chances are, it’s sucked up a lot of pollen, dirt, and assorted insect life over the spring, summer and fall. Winter will see plenty of dust and sand added to the filter element, too.
A plugged air filter can cause your engine to use a whopping 50 percent more fuel than it needs to, suffer from lousy performance, and even burn oil. Thankfully, most air filters can be changed for about 15 bucks in five minutes with simple hand tools.
Fluids: Fluids all in top shape? If you don’t remember when the last transmission fluid change, differential fluid change or coolant flush was performed on your vehicle, it’s probably overdue. Fluids should be kept topped up and fresh – not old, ineffective or leaking onto your driveway. A fresh oil change (possibly with synthetic oil), as well as new transmission and differential fluids all ensure internal components are lubricated optimally and protected from gas-sucking friction.
Fresh fluids also reach their operating viscosity more quickly, helping further reduce fuel use.
Ignition System: Your engine’s proper operation depends on a tiny and precise spark to ignite a precisely mixed blend of air and gasoline droplets. In winter, and especially at engine start-up, that ignition process is put to the test as the engine utilizes a richer and harder-to-burn fuel mixture. A fresh set of spark plugs ensures your engine gets the best mileage possible, with added reliability in cold-start situations.