I bought a new 2013 Hyundai Elantra GL Auto sedan last year, partly based on their stated fuel consumption ratings of 4.9 litres/100 km on the highway and 6.9 litres/100 km in the city. Late last year, Hyundai changed these ratings due to a “procedural error” to 5.2 L/100 km and 7.2 L/100 km.
I have a trip computer in my car and I have never seen anything better than 9 to 10 litres/100 km regardless of city or highway driving. Only once have I achieved anything close to the stated rating, and that was 6.9 litres/100 km on a trip to Barrie on Hwy 400.
The response from my dealer and from Hyundai's head office about this big difference in fuel consumption was that my engine needs to be broken-in first, and that typically takes anywhere from 8,000 to 10,000 km. Is this really true?– Praveen
The lead tester for Consumer Reports says he “wouldn't put a lot of weight into” the idea that your car won't get optimum fuel economy until it has racked 8,000 kilometres or more.
Almost anything your car encounters on the road can impact fuel economy – things like humidity, wind, and altitude, says Gabriel Shenhar, the magazine's senior auto test engineer.
Speed, fast acceleration, cold weather, full trunks and roof racks can all make your car use more gas too. But the break-in period?
“It sounds like a convenient answer,” says Shenhar.
In the magazine’s U.S. road tests, the Elantra was a bit thirstier than advertised, especially in city driving. It got 20 mpg in the city and 39 mpg on the highway (11.76 litres and 6.03 litres/100 km respectively). The Environmental Protection Agency’s (EPA) numbers for the Elantra are 29 mpg city and 40 mpg highway (8.1 and 5.9 litres/100 km).
“Typically, for most cars, we get the EPA number in our highway tests -- in this case it was one mpg lower,” Shenhar says.
This gets confusing for Canucks because the EPA numbers are often lower than Canada's. This doesn't mean Canada's cars are more fuel efficient than their counterparts down South – the two countries test and calculate the ratings differently, according to Natural Resources Canada and Transport Canada.
The published numbers come from lab tests done by manufacturers, not from road tests. They're a best case scenario.
Hyundai and Kia had to pay back (hyundaifuelconsumption.ca) nearly a million U.S. and Canadian owners of 2011 and 2012 models because the advertised fuel economy ratings weren't accurate, due to the procedural error you mention. But that was a case of trouble with the test results, not a difference between the published numbers and real world driving.
Consumer Reports doesn't test for differences in fuel economy based on the odometer reading – all the cars they test have roughly the same number of miles, Shenhar says.
“We wait until cars have about 2,000 miles (3,200 km) before we do all of our road tests,” he says. “It's so we don't cook the brakes on a car that's fresh off the lot.”
Hyundai Canada spokesman Chad Heard said the break-in period can last up to 20,000 km on new vehicles.
“The impact varies from vehicle to vehicle, but most require this time to achieve optimal fuel efficiency,” Heard says. “As the engine accumulates kilometres, the parts settle and the engine becomes more fuel efficient.”
Here's where it gets complicated again. I've written before that modern vehicles don't need a break in period – where drivers vary the speed and acceleration for the first 2,000 km – mainly because of more precise manufacturing and improvements to the piston rings.
But Patrick Brown-Harrison, with SAIT Polytechnic in Calgary, says most cars’ computers have a break-in program that delivers fuel to the engine differently for the first 10,000 km. It could affect the numbers you're getting, he says.
“The better suggestion for your reader would be to perform an actual fuel consumption report,” Brown-Harrison says. “Keep track of the litres and mileage and compare them after at least four tank fills – but drive conservatively.”
Hyundai's Heard says you can get better fuel economy by slowing down, avoiding unnecessary acceleration and by not carrying heavy loads.
“If the light ahead of you is red, don't accelerate to reach it,” he says.
If you're still not getting better fuel economy by changing driving habits, you can ask your dealer to set up a fuel efficiency test for your car, Heard says.
Send your automotive maintenance and repair questions to firstname.lastname@example.org