How does Marlow to Milan in an executive saloon on one tank of fuel sound? Impossible? Well, Volvo dared to challenge otherwise when it sent a pack of UK motoring journalists from the small Buckinghamshire village of its UK headquarters across the European continent last week. One of these intrepid road testers sent to try the fuel efficiency of Volvo’s new DRIVe models-the V70 and S80- was our reporter Tom Stewart, who kindly kept a diary to explain how Volvo converted a confessed ‘lead-foot’ to an eco-angel.

The DRIVe Story

By Tom Stewart

If you’d asked me up until recently if I thought it feasible to drive a comfortable and well-equipped executive saloon from Buckinghamshire to Italy on one tank of fuel, then I’d probably have replied in the negative. Official fuel consumption figures are often hard to achieve in real world driving, so ‘in theory’ possibly, but ‘in practise’ probably not.

With this in mind Volvo staged something different for the press launch of its new, fuel-sipping V70 and S80 DRIVe models. Instead of letting journalists loose on a set road route for a few hours we were presented with an enticing challenge: to drive from Marlow (home of Volvo UK’s HQ) to Milan (or more specifically Milan’s Malpensa airport) on just one 70-litre tank of fuel.

Preliminary research showed that with a combined figure of 57.7mpg, these 1,560cc diesels should theoretically go 888.46 miles to empty, and so should complete the 814.63-mile journey (according to the RAC’s online route planner) with almost 74 miles-worth of diesel to spare.

Armed with additional knowledge gleaned from a previous long-distance drive undertaken by Volvo that we might have as little as 35 miles-worth left in the tank at Milan, a journalist colleague and I gingerly set off from Marlow for the Eurotunnel and beyond in a brimmed S80 DRIVe.

Unsurprisingly, we weren’t exactly brimming with confidence that we’d make it all the way without topping up from the small can in the boot – not advisable on a busy Italian autostrada – and our confidence wasn’t exactly boosted by the S80’s trip computer readout which initially indicated a range of only 500 miles.

However, by setting the cruise control to where peak torque of 240Nm occurs at 1,750rpm in 5th (top) gear, that readout had more than doubled to a very encouraging ‘1,040 miles to empty tank’ by the time we were 50 miles into northern France.

So, a relaxing an easy enough trip from thereon in you may think, but we were also in competition with four other S80 and V70s crewed by equally determined pairings and so some additional rules and measures were called for: 1. Never rev the S80 above 2,000rpm. 2. Never be anything other than extremely light-footed on the throttle. 3. Always judge distances and anticipate traffic maneuvers well in advance. 4. Turn the cruise control off on long downhill slopes to allow the car to roll unrestricted on a light throttle setting. 5. Touch the brake pedal as infrequently and as lightly as possible. We ruled out three further, more extreme measures on safety grounds.

Now with 1,750rpm in top equating to just under 60mph, the A26 and A4 autoroutes could seem even longer and more tedious than usual, especially for a committed lead-foot like me. I may as well admit that I’ve been fortunate enough to have piloted many ridiculously powerful supercars across continental Europe at speeds that I wouldn’t care to mention, especially on this website. But on this, my first serious attempt at any kind of eco marathon, I was fully occupied observing the rules above while also deriving significant satisfaction from watching the fuel gauge barely move – it was still comfortably above the ¾-full mark some 310 miles into the trip.

The hours and the miles also slipped by because, just as high-speed driving requires full concentration, so does competitive economy motoring. At 60mph on the autoroute you find yourself catching the slower lorries ahead while at he same time being caught from behind by faster traffic, and this requires at least as much attention to what’s going on behind as what’s in front if you’re to maintain your most economic, ideal speed.

Even when leaving the autoroute to answer the call of nature this attention to detail extended, at least in my sorry case, to ensuring that I wouldn’t have to reverse either into or out of a parking spot, thus avoiding wasting precious thimblefuls by driving backwards for two or three car lengths!

Having left Marlow at a little before 10am, (late enough to avoid rush-hour traffic on the M4 and M25) we arrived at our overnight stop in Metz at 8.26pm French time. The trip computer showed 416 miles covered with 610 miles to empty (fuel gauge 5/8ths full) at an average of 55.8mpg.

With Milan only about 400 miles away we could now afford to feel optimistic about getting there on one tankful, but our rivals were either playing their cards close to their chests or mischievously misinforming on their own situations. And, despite our concerted efforts, our average was 1.9mpg below the S80’s (and V70’s) official combined figure.

Another slight concern was The Alps. Although we’d be taking the motorway and its many tunnels, there’s still a fair bit of ascending to reach those tunnels, plus we’d have two border crossings en route along with the ever-present possibility of a jam somewhere, all of which might dent our mpg and fuel range. Fortunately, and despite miles of roadworks in Switzerland, we weren’t delayed and so were able to fully appreciate the spectacular, autumnal Alpine scenery without undue apprehension about running dry.

By the time we’d breezed downhill into Italy and reached Malpensa we’d driven 814.65 miles, spent 17hrs 10 mins on the road, used about £57-worth of diesel, still had a safe 175 miles in reserve (fuel gauge just over ¼ full) and had averaged an impressive 56.1mpg. Despite significantly upping our cruising speed in places on day two – we once touched a heady 90mph! – we somehow managed to improve slightly on the previous day’s fuel consumption but were still 1.6mpg short of the official combined figure.

So, mission successfully completed, although more impressive was another S80 which reached the finish with an amazing 265 miles in reserve, although it did spend an extra 1hr 8m on the road. That means that an S80 DRIVe could go 1,100 miles to empty, or from the Eurotunnel to Rome on £75 of diesel if you really worked at it all the way. Even judging by our less than perfect effort, Ryanair now looks like an even more costly alternative.

Volvo S80 DRIVe SE Premium stats (read the full  road test)

Price from £24,245 otr

£30,020 (as tested)

Fuel consumption 57.7mpg (combined)

CO2 129g/km

Engine 1,560cc, 109PS @ 4,000rpm

240Nm @ 1,750rpm

5-speed manual

Performance 0-62mph in 11.7 secs, 118mph max