---- — Last week I experienced two extremes in driving pleasure from a 2013 Volkswagen Beetle.
One was the satisfaction of ultra-high fuel economy. After a week of ordinary driving, mixing some freeway runs and around-town shuffles, I averaged 47.7 miles per gallon of fuel. Let’s round that up to 48 mpg because I could have made that easily if I had exercised just a bit more moderation.
The fact that I didn’t apply a tad more moderation points to the second big delight the VW bug delivered. The car was the thrill, with the quick-flinging, dart-around movements that agile and rapid small cars attain. Plunging the accelerator pedal, pushing the car around tight-arcing turns, I had so much fun that often it was impossible to drive the Beetle conservatively.
The model I drove for the seven-day evaluation was a Beetle TDI, with a turbo-charged, four-cylinder diesel engine. It carried a list price of right around $25,000.
Diesel engines are prized for their fuel efficiency, which can top that of a gasoline-fueled engine by an alluring margin. A standard VW Beetle with a gas engine and automatic transmission earns a government fuel-economy rating of 22 miles per gallon in city driving, and 29 mpg on the highway. The feds rate the diesel version of the same model at 29 mpg city, 39 mpg highway. My average of 48 mpg in mixed driving – without even trying – may sound surprising when compared to the government estimate. But you hear similar accounts from diesel owners who top government fuel-use expectations by such large margins.
Diesel engines do not use spark plugs, which in gasoline engines are necessary to ignite the fuel – the gasoline – that powers the engine. Diesel fuel ignites automatically when compression inside the engine heats it to a combustible temperature. Diesels burn a particular fuel – called diesel fuel, of course – that enables its compression ignition.
You can’t buy diesel fuel at every gas station. But it is common enough that I never faced any problems refueling any of the three diesel-powered cars I’ve owned through the years.
What’s more, although diesel fuel currently costs about 22 cents per gallon more than regular gasoline in Massachusetts, the additional mileage you gain more than compensates for the extra cost for the fuel.
For example, if I had been driving a gas-powered Beetle last week, I might have averaged 26 mpg, calculating from government fuel-use estimates. Therefore 10 gallons of gas would have carried me 260 miles, at a cost of $37.25, using Massachusetts average fuel prices from mid week. At the 48 mpg I attained in the diesel-driven Beetle, 10 gallons moved me 480 miles, at a cost of $39.50 for fuel. That’s $2.50 more for the 10 gallons of diesel fuel, but an increase of about 84 percent in driving range.
Despite their outstanding economy, diesel-powered VWs still haven’t caught fire with Merrimack Valley car buyers, reports Charles Daher Jr., sales manager at Commonwealth Volkswagen. The VW dealership is part of family-owned Commonwealth Motors, which also sells the Chevrolet, Honda, Kia and Nissan brands at its campus in Lawrence.
“They have a strong following. There are people who love them and that’s pretty much all they want,” said Daher. “But diesels really haven’t taken off with the mainstream.”
For example, Daher estimates that only about 15 percent of Commonwealth customers who buy the VW Jetta – Volkswagen’s most popular model – choose the diesel-powered version. A lot of those are drivers who go with the Jetta SportWagon, the station-wagon version favored by people with high-hauling, active lifestyles who may also tow recreational trailers. By their nature diesel engines excel at moving heavy loads, performing more effectively and efficiently than gas motors.
Other Volkswagen models offering diesel-engine options are the Golf and Passat.
On a national scale, Volkswagen does somewhat better with its diesels than local preferences suggest. Through the first seven months of this year, diesels accounted for 23 percent of the vehicles sold by VW. That’s a little less than a quarter – not bad, but still not a groundswell of demand.
Lack of familiarity is the primary obstacle diesels face, Daher stated. Although a smattering of diesel-powered automobiles have always been available in the United States, gasoline dominates by far. The situation is exactly opposite with trucks, especially big trucks. Diesel engines rule trucking, both because they’re more fuel-efficient – a must for work vehicles that have to pay for themselves – and for their heavy-hauling prowess.
Today’s problem is that so many consumers think of diesels as truck engines only, not even associating them with cars, Daher explained. What’s more, diesels have a lingering image problem, he said. Historically they’ve been regarded as sooty and smokey, and very slow to accelerate.
Today’s tailpipe emission standards demand that current diesels burn clean. Therefore diesel engines wouldn’t even be sold if advanced engine technology hadn’t eliminated the soot and smoke. To give its diesel offerings the scoot-around acceleration automobile drivers prefer, VW turbocharges its diesels.
A turbocharger is essentially a windmill and a fan mounted on a single shaft. Pressurized exhaust gas exiting the engine spins the windmill side rapidly. The spinning windmill rotates the fan on the other end of the shaft, which rams extra air into the engine to provide added oxygen that makes fuel combustion more effective. In short, the turbocharger boosts the engine’s output.
It can take a few breaths before the windmill spins fast enough to make the fan ram in sufficient air. Therefore the boost from a turbocharger typically doesn’t occur until after a short pause – an interval called turbo lag.
The turbo lag in the Beetle TDI I drove last week was noticeable, but the up-kick in speed after a couple of eye blinks made the Volkswagen seem more spirited and playful, like it wanted a little windup before making a quick zip.
Similarly, many people test-driving diesel VWs at Commonwealth gain a higher opinion of the engines when they notice their fast action and rapid movement.
“People see that they move pretty quick. They see that the fuel economy they’re getting is second to nothing. Then they’re hooked,” he stated.
The only quality Volkswagen may need to see more people move to its diesel-powered automobiles is patience.
Jeffrey Zygmont is an author of fiction and non-fiction books, and a long-time auto writer. Contact him at www.jeffreyzygmont.com.
2013 VW Beetle TDI
Vehicle type: 2-door, 4-passenger, front-wheel-drive compact convertible
Price range: $24,290 to $28,440 (plus options)
Warranty: 3 years/36,000 miles basic warranty; 5 years/60,000 miles powertrain warranty; 12 years/unlimited miles corrosion warranty; 3 years/36,000 miles roadside assistance; 3 years/36,000 miles free scheduled maintenance
Engine: 2.0-liter turbocharged I4 diesel
Power: 140 horsepower at 4,000 rpm; 236 lb.-ft. torque at 1,750 rpm
Base transmission: 6-speed manual
Fuel economy: 28 mpg city; 41 mpg highway
Wheelbase: 100 inches
Length: 168 inches
Width: 71 inches
Height: 58 inches
Weight: 3,073 pounds
Fuel capacity: 14.5 gallons
Turning circle: 35.4 ft.