13th Mobil Economy Run
The problem facing organisers and sponsors of the Mobil Economy Run is not to prove how far cars can travel on each gallon of the product, but to prevent such incredible results that the public dismiss the whole event as a “rigged” stunt to provide good advertising copy. Last year the weather waged in with gales, snow and rain, which certainly conspired against the smaller cars, but this year the route was a little harder, and the weather much better, so that once more the small cars turned up good results and the larger cars were rather worse than before.
It could be called a revenge for B.M.C., ousting Rootes and Renault for top honours in Classes 1 and 2 respectively, proving that a standard Mini-Minor can give 58 miles per gallon while averaging 30 m.p.h. over a tough 1,100-mile-route, or a Morris 1000 fractionally better than 50 m.p.g. The Hillman Hunter definitely proved the claims of economy made for it by bettering 40 m.p.g. and taking first and second class positions, while the over-2-litre automatic class was dominated by the V8 Daimler 2 1/2-litre which beat a V6 Zephyr.
Motor Sport, represented by the Editor’s assistant and, as co-driver, one of the Editor’s daughters, took part in the Press sweepstake section in a Hillman Minx hired from an agency by the organisers, just to prove how standard the cars can get. Apart from tuning the carburetter for maximum economy and increasing the tyre pressures to 27 p.s.i. all round, the recommended limit in the manufacturer’s handbook, no special preparation was done. The 40 competitors however had taken great pains to ensure free running and rigorous scrutiny before the event, and afterwards in the case of award-winning cars, ensured that there were no “fiddles.” All cars were on radial ply tyres, which slightly reduce rolling resistance, and it was notable that in all classes but one the leading cars were shod with Michelin X steel-ply equipment. Observers were carried in the cars to make sure the drivers did not coast down hills in neutral or infringe traffic regulations, pursuing the logic of fair play to its limit.
Starting from Edinburgh, the first day’s route went over the Grampian mountains to Dufftown before the southward run to Pitlochry, covering 314 miles in the day. Putting 30 miles into each hour was no problem on the traffic-free roads, indeed those who had not practised needed the proverbial patience of Job to keep the speedometer on 35-40 m.p.h. all day on the wonderfully inviting routes chosen, and there was plenty of time to consider that Scotland produces good racing drivers because anyone who wants to can play boy-racers all day, every day without endangering or annoying anybody.
To drive economically we treated the car as though running it in, little more than breathing on the accelerator pedal to maintain speed and accelerating at a rate that would hardly do credit to an elderly cyclist. Uphill, the car was left in top gear as long as possible but not until the whole lot shuddered as some experts advocate. Since braking clearly dissipates energy one tries to pace the car for corners by the throttle alone, though on the downhill stretches the process becomes far more exciting. We realised that Hillman Hunters equipped with overdrive were scoring on the downhill parts since on all but the steepest gradients the Minx needed a little throttle to maintain speed, whereas the o’drive cars on the same axle ratio would pick up speed.
The second day’s run was completed in heavy mist and rain, travelling south-west to Rest and be Thankful, through Glasgow and across the Lowther HIlls to end the 320-mile route at Carlisle. The roads chosen were almost entirely second-class or pure mountainous, yet some very good fuel consumption figures were being reckoned and the Minx was giving in the region of 40 m.p.g. The third day put paid to that, however, going straight onto the Cumbrian mountain range then down the M6 motorway at a 50 m.p.h. average. After lunch was the dreary, traffic-ridden and time-consuming itinerary through Wigan, Bolton, Manchester, before crossing the Pennines, northwards towards Newcastle, where a good deal of fuel was used making up time. An easy run-in to Edinburgh completed 457 miles after midnight, and our fuel consumption for the day could have been a more realistic 30 m.p.g., since the overall figure was a shade under 37 m.p.g.
Well, are the figures you see in the advertisements realistic? Not so far as the man in the street is concerned, for this type of driving is both an art and a science, many of the competitors having a most professional approach as they time each mile to make sure they do not cover the route too quickly, or too slowly, as co-drivers read every contour and every corner on an ordnance survey map to enable the driver to adjust his speed. Had we been out for a very gentle tour on this route, going a bit faster up the steep gradients and using the gears coming down, our consumption figure would have been nearer 33 than 37 m.p.g., about 25% worse than the similar model taking part in the competition. But it is a fascinating exercise, and each year the regulars come back to do even better, the entry list being handsomely over-subscribed.
Since each class embraces a 500 c.c. bracket (500-1,000 c.c., 1,500 c.c., 1,501-2,000 cc., and over 2,000 C.C. for automatic transmission), the class-winning cars normally have the least engine capacity so each entrant elects the car he wants to drive and another which he is prepared to use if necessary at the top end of the scale, by which means the Hants and Berks Motor Club organisers get a selective cross-section of British and foreign models. Each car is set a target figure, worked out scientifically, by what is called the Hants and Berks formula, so the entry which exceeds the target by the greatest margin is the overall winner. – M. L. C.