VOLKSWAGEN THINK BLUE CHALLENGE
What’s Hot: Seemingly defying physics by obeying... er, physics.
What’s Not: Driving in Canberra’s winter with the heater off
X-Factor: The most intense driving experience possible at legal speeds
Vehicle type: Volkswagen models with BlueMotion Technology
|Golf 103 TDI Comfortline with BlueMotion||103kW/320Nm||5.3l/100km|
|CC 125 TDI||125kW/350Nm||5.7l/100km|
|Tiguan 103 TDI six-speed manual||103kW/320Nm||6.0l/100km|
|Touareg V6 TDI||180kW/550Nm||7.4l/100km|
Volkswagen is pretty proud of its BlueMotion technology, that being the collective term the German giant applies to the suite of features aimed at reducing fuel consumption.
Its focus is on reduced friction and weight, greater use of a vehicle’s kinetic energy, and improved aerodynamics.
The technology has now filtered through much of Volkswagen’s local line-up. This was the point Volkswagen Australia was keen to assert with its recent Think Blue Challenge event.
Pitting the invited media against each other in a selection of BlueMotion-equipped models, the challenge was to return the best trip-computer l/100km figure over two prescribed road loops.
Sounds like a drive in the park doesn’t it?
But as those in the know will tell you, when it comes to fuel economy there’s far more to extracting the best fuel consumption from a car than simply moderating the weight of your right foot.
While all were turbodiesels, transmission choices varied from the H-pattern manual of the Tiguan, to the DSG automatics of the CC and Golf, and the eight-speed torque converter automatic in the Touareg.
Weights ranged between 1346kg for the Golf, to the 2159kg Touareg.
Volkswagen had chosen two distinct routes for the challenge, with Golf and CC assigned to one route, and the SUV models assigned the other.
Both were chosen to replicate real-world conditions, with roadworks and traffic lights on the Golf/CC route, and an abundance of steep climbs and dirt roads for the SUVs.
To add a twist to the Challenge, both routes started and finished atop Mt Stromlo in Canberra’s west.
This meant that a tantalisingly economical four kilometre initial coast down the mountain was negated by a grinding climb on the return leg.
To set the bar, Volkswagen had former Australian Rally Champion Ed Ordynski - also noted for his eco-driving prowess - set target figures for each of the cars.
We were no longer just competing with each other, we were now competing with Australian motorsport royalty. Cor, blimey.
Radio, lights, and aircon were all set to off, windows up, and passengers jettisoned; we were going to give Mr Ordynski a run for his money.
Armed with the knowledge that each car chosen was a turbodiesel, had an automatic fuel cut-out when coasting in gear (aside from CC) and an instant fuel consumption readout on the trip computer, the challenge was on.
Golf 103 TDI Comfortline with BlueMotion Technology
Setting off down the hill in the Golf, the expected free ride of the route was not as simple as planned.
Accessing the fuel cut-out (zero consumption) requires the DSG transmission to remain in gear, which therefore induced engine braking - even when sixth (top) gear was manually selected.
This is okay as long as the downhill gradient is sufficient to maintain momentum, but plateaus in the road required momentary selection of neutral to maintain enough momentum to continue to the bottom without throttle.
Note that when in neutral, some fuel is required to keep the engine running.
When on the flatter part of the loop, minimal throttle was the theoretical key. While accelerating, taller gears were selected as soon as possible via the manual shift mode, and braking was minimised through corners in the interest of conserving momentum.
With little more than shoe-weight on the throttle, it was possible to hold the speed at just below 80km/h - a speed we chose to minimise wind resistance. (Why 80? Purely the gut instinct of this driver.)
When approaching traffic lights, careful judgement was applied to the timing of the lights.
If a short stop was anticipated, we coasted; but if it looked like a long stop, arriving relatively quickly to utilise the benefits of the start/stop system seemed a logical strategy.
Volkswagen claims that the engine needs to be off for at least 15 seconds for this system to be of any efficiency benefit.
When it was time to scale Mt Stromlo once more, the decision was made to balance the labour involved in the climb, against the overall time spent doing it.
This entailed approaching at a decent cruising speed while holding minimal throttle, and maintaining the tallest gear possible for each part of the climb.
The result? A reading of 4.3 l/100km. A full litre better than the Golf’s ADR combined figure, but 0.3 litre behind Mr Ordynski.
Touareg V6 TDI
The Touareg V6 TDI was up next, and proved much easier to coast down the four kilometre Mt Stromlo road.
Top gear was selected manually, but engine braking was less intrusive due to the slip from the torque converter.
No doubt the extra inertia generated by the 813kg heavier Touareg also helped here.
Heading into the hills for the dirt road section, the same cruising policy of minimal throttle, maximum gear choice was applied.
The dirt section was quite steep in parts, forcing the Touareg down to second gear.
This still required delicate throttle application though, as any energy lost through wheelspin would soon be compounded by traction control intervention, and put a big dent in our crucial momentum.
A 7.5 l/100km result was showing on the Touareg’s trip computer by the time Mt Stromlo’s summit was reached - 0.1 l/100km behind the Touareg’s ADR combined figure, and was a full half-litre behind the Ed Ordynski target.
CC 125 TDI
The CC 125 TDI uses an uprated version of the Golf and Tiguan’s 2.0 litre turbodiesel engine, also with six-speed DSG transmission.
Unique in this group though is the CC’s automatic declutching function, which automatically selects neutral when coasting.
This of course negates the in-gear fuel cut-off function of all the other models tested.
This suggests that in day-to-day driving, it may be marginally more efficient to coast in neutral when slowing, rather than relying on engine braking.
Aside from this function, the same driving technique was used as in the Golf, which yielded a 4.9 l/100km result upon return to Mt Stromlo.
This is just 0.1 l/100km behind Ed’s benchmark, and 0.8 l/100km better than CC’s ADR combined figure.
Tiguan 103 TDI
Driving the Tiguan saw us return to the SUV loop, and the six-speed manual allowed full control over gear selection.
A helping hand remained though in the form of the ‘gear-selection alert’ on the dash, aimed at informing the driver of the most efficient point to change up or down a gear.
We found this to be pretty accurate in its advice, advising a change in ratio as soon as the revs moved outside the 103 TDI’s 1750-2500rpm maximum torque window.
Once again, the same throttle position, gear selection, and momentum conserving driving style was applied as the other vehicles, which returned a 5.5 l/100km figure at the end of the loop.
This was 0.5 l/100km behind Ed’s benchmark figure, but significantly 0.5 l/100km ahead of the Tiguan’s ADR combined figure.
It may have been instructive, but the Think Blue Challenge honestly gave little indication of what the models featured would be like to live with in real-world conditions.
Aside from moving too slowly to give a real impression of the cars’ behaviour, the drivers’ attention was heavily prioritised on delivering the best fuel consumption.
Volkswagen’s purpose with the challenge was to demonstrate clearly just how economical the BlueMotion range of Volkswagens can be, if you put your mind to it.
With the exception of Touareg V6 TDI, all models easily beat their official ADR combined figures. But many of the ‘crawling along’ fuel-saving techniques mentioned here would win you no friends out on the roads if used day-to-day.
But we can learn from them. Such focussed driving is a darn good intellectual workout, and, surprisingly, quite engrossing at the wheel.
Did we win the challenge? Not overall, but your correspondent did manage an equal first with the Touareg’s 7.5 l/100. The best result from the worst performer relative to expectation. Interesting.
- VW Golf 103 TDI Comfortline with BlueMotion Technology - $34,490
- VW Tiguan 103 TDI six-speed manual - $35,990
- VW CC 125 TDI - $54,990
- VW Touareg V6 TDI - $77,990
|Results Table (l/100km)|
|Golf 103 TDI||5.3||4.0||4.3|
|VW Touareg V6 TDI||7.4||7.1||7.5|
|VW CC 125 TDI||5.7||4.8||4.9|
|VW Tiguan 103 TDI 6spd Man||6.0||5.0||5.5|
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