You probably know the feeling well. You are climbing those scenic south European mountains in your faithful old classic. Initially, all is well; the driving gloves are snug and the tires are chirping lightly as you entertain yourself through the many hairpins. But as you gain altitude, the car begins to behave as were it a century older than it is.
This is of course due to the thinner air and thereby reduced oxygen content of the air at high altitudes. This results in reduced engine power because there is less air to ignite the gases in the combustion chambers of the engine. Generally, an engine loses three percent of its nominal power for every 300 meters of altitude gained. This means you can lose up to 20% of your vehicle’s horsepower if you drive from sea level up to 2,000 meters. It’s at this altitude a number of famous mountain passes in the Alps and the Pyrenees are located.
So what is one to do, when your competent tourer gets altitude sickness and turns impotent? Well, you could refrain from forcing the car up there in the first place and exposing it to those humiliating forces. That would however be a rather sad solution as there are numerous great drives to be experienced in the mountains for that most devoted of drivers. This is the reason why many instead choose to deal with the humiliation by imposing a degree of self-control, and simply accepting the reduced engine power which is at your right foots disposal as you navigate those oxygen-starved twisty mountain passes.
Yet, there is a small trick which potentially could solve the issue after visiting a local service station. At altitude, an engine requires lower octane to run. So if you for example could purchase 85 octane fuel somewhere in the mountains, the engine would suddenly run cleaner and better again. The only caveat being that it of course requires said low-octane fuel to be obtainable and that you haven’t already got a tankful of the premium high octane fuel which we of course normally treat our beloved classic cars to. Then – with the ignition adjusted to suit the new conditions, ensuring the perfect spark at the perfect timing – bliss will be reinstated. Granted, it all sounds a little difficult and awkward, which perhaps explains why it is thus far just a theory of mine, rather than common practice. Thus far, while on my own roadtrips, I have endured with reduced power from my enigmatic and suffering engine.
And as if that wasn’t bad enough.
The tire pressure is also under pressure (pardon the pun).
In the much colder and different atmospheric pressure conditions of the mountains, the tire pressure will drop. And in theory, all kinds of devilish problems will make their entrance
- Reduced fuel economy
- Inferior precision and ‘feel’ from the steering
- Uneven tire wear
- Potential tire failure if pressure drops more than 6 psi below the manufacturer’s recommendation
However, at least the tire pressure can be managed at the nearest service station before climbing further towards the sky. Unless you know precisely how much pressure will fall, it’ll never be scientifically exact but maybe just a small increase will be adequate for a smaller trip?
What experience do our ViaRETRO readers have from doing at altitude? Please share your advice and top-tips on taking the classic car to the top of the world? The comments area below is at your disposal…