What's your car doing on the Susten Pass?

Fuel vapour lock is a minor motoring bogey. But it can be a very tedious one. What happens? Take a highish climb, with lots of low-gear work. Engine gets hot. Vaporisation starts in the fuel system. Bubbles of vapour form. And the flow of petrol is interrupted.

Provided you keep going, cool air usually counteracts this – and the most you’ll feel is some slight hesitation in acceleration. But now stop. The heat builds up. And vapour lock then can actually prevent the car restarting at all.

BP in twenty-car test. As new cars are produced by the manufacturers it is necessary to make sure the petrols you buy are up to the new standard of vapour lock resistance demanded.

So, extensive volatility tolerance tests were recently carried out on the Susten Pass (south of Zurich). In these, BP collaborated with the Swiss authorities concerned.

Twenty cars of recent make were used (including the Austin 7, Fiat 1100, Chevrolet Bel-air, Ford Anglia, Hillman Minx, Renault Dauphine, Simca Aronde, Vauxhall Cresta, Vauxhall Victor). After warming up, the cars mounted the pass to a distance of 6-1/2 miles with a climb of 2,260 ft. A hundred runs were made.

The results are now being analysed, for your benefit as a motorist.

Most tested in the world. BP Premium Petrols (BP Super-Plus and BP Super) are the most tested petrols in the world. That is why they give you top performance in every way.

If you would like to know more about this …