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2010 VW Golf Wagon TDI
2010 VW Golf Wagon TDI

Faceoff: Gas vs. Diesel

Which Golf is best? It depends where you drive Add to ...

Two of three finalists for the Canadian Car of the Year award, presented by the Automobile Journalists Association of Canada, are Volkswagen Golf variants.

The AJAC winner, to be announced Feb. 11, will be either a diesel-powered Golf wagon (named best family car under $30,000), a gasoline-powered two-door Golf GTI (voted best performance car under $50,000), or another diesel newcomer, the BMW 335d (named best new luxury car).

Win or lose, snagging two out of three finalist spots underlines the competence of Volkswagen's new Rabbit-replacement range.

But which delivers the most satisfaction, gasoline or diesel?

In a coincident competition, your EcoDriver reporter drove both vehicles earlier this winter. Our gasoline-powered Golf was not the GTI sports model that's a finalist, however, but a regular hatchback with Volkswagen's 2.5-litre workhorse. Our goal: To explore the differences between these two types of powerplants in identical urban conditions, rather than declare an all-out winner.

First comes price. The least-expensive diesel four-door costs $2,400 more than its gasoline counterpart. The TDI (turbo diesel injected), as the diesel is marketed, sells for $24,975 as a four-door hatchback with a trim and equipment level Volkswagen Canada calls Comfortline. The Comfortline gasoline model is $22,575. (Two-door Golfs and the base four door are gasoline only.)

We asked Volkswagen for test cars identical except for engine type. What we got, though, was the diesel wagon, the same vehicle that won its class at the AJAC test festival (2.0 litres, four cylinders, turbocharged, 140 horsepower, 236 lb-ft of torque), followed the second week by a four-door hatchback with its standard gasoline engine (2.5 litres, five cylinders, not turbocharged, 170 hp, 177 lb-ft).

Automatic transmissions carried the power to the pavement in either case. The wagon was equipped as a Highline, rather than Comfortline, but for the purposes of this examination we'll forsake discussing the niceties. And just drive.

The thrust of a TDI engine is something remarkable and it's experienced every time a traffic light turns green or circumstances call for foot-to-the-floor acceleration. The wagon's accelerative power has an addictive quality to it as a result, and somehow the rapid progress is rendered all the more satisfying when you remember the engine's fuel efficiency is as remarkable as its torque.

But let it be noted that the rocket launch is not something everyone will applaud. A long fraction of a second passes after depressing the accelerator before the heated rush of the turbocharger boost comes into play. Whereas there's no such lag in the response of the gasoline engine when pulling away from a standstill, making it smoother and more satisfying in stop-and-go suburban traffic.

Acceleration figures support this impression. In our testing from zero to 60 kilometres an hour, the TDI took 4.8 seconds, the 2.5 took 3.6. Zero to 100, Volkswagen claims 9.1 and 8.6 respectively - again, advantage to the 2.5.

Another diesel downside on subzero mornings is the long wait before the heater started blowing heat into the interior. It took 15 minutes or more in stop-and-go traffic to reach the operating temperature of 90 degrees. The four-door with the gasoline engine warmed up faster. Heated front seats, standard at the Comfortline level, were a great help, noticeably more so in the wagon.

The six-speed automatic transmission gives Volkswagen/Audi cars a huge advantage over competing vehicles. Instantaneous shifting among the gears pays off with acceleration roughly equal to that of a manual transmission and, in many cases, superior fuel efficiency. Generally, automatics are responsible for higher fuel consumption. With its greater efficiency, the DSG (dual clutch gearbox) must eventually become the industry standard, assuming its long-term durability equals that of traditional automatics.

The city fuel-efficiency rating of the gasoline-powered Golf is significantly improved with DSG rather than a manual, dropping from 10.4 litres/100 km to 9.2, according to Natural Resources Canada test methods. A diesel four-door hatchback, however, is rated at 6.7 with either manual or DSG.

This takes us to our own comparison. In our urban driving, the diesel held a clear advantage, consuming 20-per-cent less fuel than the gasoline Golf.

Our TDI average of 7.9 litres/100 km did fall considerably short of the Natural Resources Canada city rating of 6.7 - as expected, reflecting our cold conditions and winter tires and the government agency's unrealistic test results. Our 2.5 hatchback came closer to matching the advertised figure by averaging 10.1 against the published 9.2.

The diesel fuel was less expensive as well, at 94.9 cents a litre on a day when regular gasoline commanded 99.9. (But it should be remembered diesel was the more expensive fuel a year ago.)

Consumer Reports recommends the TDI over the gasoline Jetta and the same reasoning would apply in the case of the Golf. Diesel Volkswagens' superior retained value plays a large part in CR's thinking. Example: According to the Canadian Black Book, a 2006 VW Jetta with a luxury package and 80,000 km would range in selling price from $12,200 to $16,525 with a 2.5 engine, but $15,900 to $20,275 as a TDI.

Actuarially inclined auto journalists invariably recommend the TDI. Our call? In this case, driving pleasure trumps prudence.

We favour the 2.5 gasoline engine for any Golf destined to accumulate most of its kilometres in urban driving. This car is simply nicer in stop-and-go traffic. The terrific, muscular engine provides pure pleasure in its responsiveness while achieving acceptable fuel efficiency.

The TDI becomes the more pleasurable at highway cruising speeds. The diesel engine's incredibly low consumption and long range between filling-station stops come into play. The final determinant is that the annoying lag between pressing the accelerator pedal and actually accelerating virtually disappears at higher speeds.

My pick for AJAC car of the year, incidentally, is the BMW 335d.

But both of these Golfs are winners too - as much as they differ from each other.

globedrive@globeandmail.com





2010 Volkswagen Golf Wagon TDI Clean Diesel

2010 Volkswagen Golf 5-Door 2.5L

Type

Four-door wagon

Four-door hatchback

Base Price

$22,675; as tested, $33,235

$21,175; as tested, $26,635

Engine

2.0-litre, DOHC, turbocharged, diesel inline-four

2.5-litre, DOHC, inline-five

Horsepower/Torque

140 hp/236 lb-ft

170 hp/177 lb-ft

Transmission

Six-speed automatic with manual function

Six-speed automatic with manual function

Drive

Front-wheel-drive

Front-wheel-drive

Fuel Economy (litres/100 km):

Government lab test result, 6.7 city/4.6 highway; our actual urban driving 7.9; low-sulphur diesel fuel

Government lab test result, 9.2 city/6.9 highway; our actual urban driving 10.1; regular gasoline

Alternatives

Hyundai Elantra Touring, Audi A3, Mazda5, Toyota Venza, Mercedes-Benz B200

Volvo C30, Acura CSX, Mazda3, Subaru Impreza

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