Volkswagen Golf TDI versus Golf TSI 2015: Two Tests Over 4,000 km

Are you familiar with the urban legend, or popular belief, that the seventh child in a family is always endowed with special gifts? There is a temptation to draw a technological parallel, and apply it to the seventh generation of the Volkswagen Golf. This is one family that is doing very nicely, thank you, with some thirty million copies produced over four decades, making it the second-best selling model since the car was invented.

The new Golf was chosen World Car and European Car of the Year, and went on to become the first non-Japanese car to be chosen Car of the Year in Japan. Since its arrival in Canada as a 2015 model, it has received the AJAC award for Best Small Car over $21,000, and stands an excellent chance of being chosen Car of the Year, regardless of category. It is the same story with the North American Car of the Year award, for which the entire Golf family is a contender: the gasoline-powered TSI, the TDI Diesel and the GTI, which remains the most sporting version.

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However, Car Guide beat them to the punch and chose the new Golf and its sporting variant, the GTI, as Cars of the Year for its 2015 edition, published a few months back.

Two Golfs are better than one 

Given how popular the Golf is in Canada, I told myself that I had no better choice this year than to report with all my gear to the test days where I could vote on these awards. Two consecutive long drives took me first to central Michigan, and then the following week to Niagara Falls, Ontario: two long freeway journeys interrupted by short local trips.

It was an ideal way to investigate and learn every detail about the comfort, behaviour, ergonomics, practicality, performance and real-world fuel consumption of these new models, particularly as I was able to make the first trip in a gasoline TSI, and the second in a diesel TDI. With a little luck, I would have a clearer answer than ever to a question we are constantly asked: if I buy a Golf, should it be gas or diesel?

At first glance, apart from the colour and the TSI and TDI trunk badges, the two Golfs are outwardly very similar, particularly as in this case, as they were both in top-of-the-line Highline trim, with the same 17-inch Geneva alloy wheels shod with 225/45 ContiProContact tires, making it all the easier to compare how they drive.

Additionally, the TDI has twist-beam rear suspension, while the other models are independent all round. A curious choice, doubtless intended to offset at least in part the inevitably higher cost of the diesel engine. With identical equipment, the TDI nevertheless remains the more expensive of the two.

More refined and enjoyable than ever 

The new Golf is the first to be built on Volkswagen’s new MQB platform for front-wheel-drive cars with transverse engines; its simplified and less expensive modular architecture made it possible to design these new compacts to be longer, wider and more spacious, yet stronger and lighter. They are 2.8 cm lower, with better aerodynamics yielding a drag coefficient (Cx) of 0.29, down from 0.32.

The two cars I tested were in Highline trim, and the base prices were $29,495 for the TSI and $30,995 for the TDI. Add $1,400 for the automatic transmission and $2,195 for the Technology package, which includes an efficient navigation system with a 5.8 inch touch screen, a CD player, excellent xenon headlights that peer around corners like flashlights, LED running lights, a powerful and crystal-clear Fender sound system with eight speakers and a subwoofer, and a forward collision warning system.

The first word I wrote in my notebook after jumping into the TSI was “refinement”. The new Golf is impeccably elegant and quiet, with superb interior design and finish. The driving position is unencumbered, and the controls are well placed and easy to use, for the most part. On the other hand, why put the volume control on the left side of the steering wheel and the station selector on the right? And I never did get used to the cruise control buttons, which do not project far enough.

The designers deserve applause, however, for slender A pillars and low-mounted side windows and rearview mirrors that provide excellent forward vision. The same goes for the gauges, the perfectly clear screen, the well lighted controls and the numerous handy outlets and storage compartments.

Cargo space is wide and accessible, with split-folding rear seat-backs. To open the hatch, you press the top of the VW badge, which swivels automatically when you shift into reverse to reveal the backup camera. This means that the camera lens stays clean, even in winter.

The front seats are well-designed and look good. They are very comfortable initially, and provide good support, but I found myself squirming around after a few hours at the wheel. It was perhaps inevitable after 8, 10 and even 12 hours of driving. Or maybe it was just me.

I enjoyed the two Highline versions, but testing a Golf TSI in Comfortline trim for the AJAC awards convinced me that it offered all the refinement and dynamic characteristics of the high-end vehicle, and was surprisingly well equipped for the price of around $24,000.

Torquey turbos 

The engines in the seventh-generation Golf are also new. The TSI has a gasoline powered direct-injection turbocharged 1.8 litre four producing 170 hp at 4,500 rpm, but more importantly 200 lb-ft of torque at just 1,600 rpm. This lively and flexible power plant takes the TSI from 0 to 100 kph in 8.5 seconds with the 6-speed automatic transmission. The quarter-mile takes 16.13 seconds at 141.8 kph, and the 80-120 kph passing manoeuvre takes 5.85 seconds. These figures were achieved on regular gas. Unusually for a turbo engine, that is what Volkswagen recommends. You'll be able to feel the difference in your wallet.

The TDI’s turbodiesel four still displaces 2.0 litres, but all the components are new. Output is 150 hp at 3,500 rpm and 236 lb-ft of torque at 1,750 rpm. Performance: 0-100 kph in 9.0 seconds, the quarter-mile in 16.62 seconds at 136.8 kph and 80-120 kph in 6.95 seconds with the excellent dual clutch DSG 6-speed automatic.

The figures confirm that the TDI and the TSI are very close in performance, thanks to the turbo in both cases. The gasoline version has a slight edge in speed and acceleration, and the diesel remains more economical, as expected.

What advantage does the TDI have in terms of fuel consumption, you may wonder? It’s an obvious question, given the Golf diesel’s status as an economy champion. Yet the choice is now tougher than ever because the new and thoroughly modern gas-powered turbo in this TSI offers more than high performance and flexibility.

A more difficult choice 

Over a total distance of 2,354 km, and maintaining a speed of 118 kph (or 73 mph) on the freeways, I achieved an average of 6.98 l/100 km for the TSI. This included return journeys between the hotel in Chelsea, Michigan, and the test headquarters for the North American awards in Hell Creek, a combination of city and secondary-road driving.

By comparison, I got an average of 5.15 l/100 km with the diesel-engined TDI over a total distance of 1,602 km. Again, I kept to a “sub-ticket” speed of 118 kph on the freeways, and made several return journeys that involved city driving between the hotel in Niagara Falls and the AJAC awards base camp a few kilometres away.

So which one should you choose? Bearing in mind that the price difference between regular gas and diesel is currently 20 cents in the Montreal area, it would take about 15 years to make up the difference of $2,500 between the base prices of the TDI and TSI versions, assuming a typical 20,000 km a year. No wonder Volkswagen tried to reduce the gap by fitting lower-cost rear suspension to the TDI.

That said, the price difference between regular gas and diesel was a mere 3 cents where I filled up in Ontario. Try finding that in our part of the world! The Golf TDI therefore appeals more than ever to high-mileage users, particularly when comfort and performance are virtually identical in highway use. If you drive 60,000 km a year – not all that unusual in Quebec – it will take you five years to make up the price differential. That will leave more money in your pocket for the following five years, even with the higher maintenance costs for the TDI.

For the rest, the new Golf TDI and TSI are wonderfully practical, agile and refined compact cars that richly deserve the honours heaped upon them. Thanks to the more powerful GTI, which I very much enjoyed driving during the annual test bonanza, we are already spoiled for choice. With the new all-wheel-drive 296 hp Golf R coming soon, the choice becomes almost agonizing.