SAVING PETROL

Press, Volume LXXIII, Issue 22194, 10 September 1937, Page 19

SAVING PETROL

Problem of Many Owners IMPORTANCE OF SPEED For the motorist of moderate means, the question of petrol consumption always has been, and always will be, of vital importance. Fuel 'bills, if they seem excessive, become such a sore point that the motorist is apt to go to all sorts of lengths to reduce them, including that of cutting the carburettor down so finely that the car becomes sluggish and lacks power. This question of petrol consumption needs sane and thoughtful consideration. If a motorist must run a big car, he cannot expect the same mileage from one gallon as can the owner of a smaller vehicle of less comfort; if he persists in driving fast, his figures will compare very badly with those ot the quieter driver; while, if ho is one of those individuals,who drive in a scries of jerks and always use the car’s full acceleration when getting away from rest, he must inevitably pay for his roughness in heavy petrol consumption. Modern cars, without exception, it may be said, will deliver a reasonable number of miles for every gallon of petrol put into the tank, if they arc driven in a sensible way, and altering the carburettor from the standard setting will do little, if any, good. The makers endeavour to establish a setting which will enable the engine to develop the full power for which it is designed, and which will give a reasonable rate of fuel consumption. If the carburettor is cut down to such an extent that some of this power is lost, there is not much point in running such a big car. In any event, the throttle will have to be opened so wide on hills and during acceleration that the improvement will be very small. A Moderate Gain In the case of one particular sixcylinder sedan car, normally driven rather fast, the fuel consumption with the standard carburettor setting is between 17 and 18 miles to the gallon. To improve upon this, the owner installed a special metering pin to cut down the flow of petrol from the jet. There was a noticeable loss of power, a definitely increased tendency to detonate, and the fuel consumption dropped to between 19 and 20 miles to the gallon. Needless to say, the car is now back on the standard setting, and the owner is philosophical enough to admit that if he insists on driving rather fast, he must pay for it. Quite likely, if this car were regularly driven at about 40 miles an hour on long runs, tha fuel consumption would exceed 10 miles to the gallon by a good margin. Incidentally, some care is taken in this case to keep the .combustion chambers clean and the vttlvcs sealing properly, two essentials to good petrol mileage. In general terms, if a car In perfect mechanical condition will deliver 26 miles to a gallon at 30 miles an hour, at 60 miles an hour this will drop to about 17 miles to the gallon. That is the effect of speed on fuel consumption. If the owner of a big car which is in excellent order, and is running with the standard carburettor settings, is still not satisfied with the fuel consumption. he should either reduce the speed at which he jirives or sell the car and obtain a smaller one. Faulty Driving Methods There arc, of course, other factors besides speed which affect fuel consumption, and one of the most important is the manner in which the car is handled. Pushing the accelerator to the floor boards, for example, every time the car is accelerated, will pump a great quantity of petrol into