Do cars suffer from acute mountain sickness? If so, what is the prescribed treatment? Cheryl
Cars run out of breath at higher altitudes. As do people. Because the air gets “thinner” (less densely compressed by gravity). With less oxygen, internal combustion engines cannot burn fuel as efficiently, and that means they produce less power.
All cars will have more grunt when they are at the coast than when they are in the highlands. The rule-of-thumb formula for power loss is about 10 per cent per 1,000 metres of ascent.
As cars are not usually driven at full power, the change is negligible between Mombasa (sea level) and Mtito Andei (1,000 metres) but it is noticeable by Nairobi (2,000 metres), quite distinct on the moorlands of the Aberdares (3,000 metres), and if there were tracks to the top of Mt Kenya (5,000 metres) or Kilimanjaro (6,000 metres)...the engine might still run on flat ground, but might not have enough power to peel a banana, never mind summit a glacier.
If your car’s power output is, say, 100 HP, about 20 percent of that will be used by the car to simply operate its own moving parts, leaving you about 80 HP to propel its overall weight. By the time you reach the Aberdare moorlands, you will be driving a 50 HP car.
Turbocharging can ameliorate this effect, but as much by giving a car a better power-to-weight ratio to start with than by reducing the rate of decline.
Another minor compensator can be adjustment of the ignition timing (within quite small limits), linked to which cars can cope with slightly lower octane fuels when they are in the mountains than when they are on the beach.
None of these factors significantly adjust the inevitable formula of “higher altitude/lower performance”. And in most motoring circumstances they don’t need to – a trip to the office, the school run, popping down to the shops, going on a family safari...you will rarely (need to) use more than 50% of your car’s maximum power anyway.
The decline is more significant for higher speed highway cruising, especially when you want a surge of power to overtake in traffic or maintain speed on steeper inclines, when max power can be an important resource.
Not much you can do about that, but there are ways to avoid making things worse. Air conditioners, for example, are a significant drain on engine power. So, as you ascend to cooler climes, turn them off when you need to make the most of rare overtaking opportunities.
Humans can cope quite well with altitude change...at lower levels... and, unlike cars, they can “train” and “acclimatise” to a significant degree.
If you spend some days at higher altitude and do some vigorous exercise, your body will decide you need to improve your uptake of whatever oxygen is still available and produce more red blood cells to enable that.
A coastie who is not acclimatised will “notice” a change at 2,000 metres, puff and wheeze a lot at 3,000 metres, and become prone to Mountain Sickness (extreme breathlessness and even pulmonary oedema) above 4,000.
At a higher altitude than that, the effects become potentially lethal, as MS can become Acute MS. The victim either needs access to an oxygen breathing apparatus or must descend without delay.
The early downside of going up includes breathlessness, muscle fatigue, a sense of indolence and perhaps a headache. The upside of going down is that recovery is usually very rapid and complete.
Even fully fit and acclimatised people will find the going a lot tougher above 4,000 metres, and feel a lot less than their best. The wise slow their progress accordingly, even if they “could” go quicker.
The human body’s ability to compensate is not unlimited. On Mt Everest (peak at about 9,000 metres), ground above the 7,000-metre level on the final approaches towards the summit is known as “The Death Zone”.
You can’t live up there for very long. The time limit climbers can spend above that level is not negotiable. The number one first aid kit is an oxygen tank.
This does beg the question of whether cars wishing to operate at extreme altitude could be fitted with auxiliary oxygen supplies. The catch is the sheer quantity of air a car engine needs.
In round numbers, an internal combustion engine needs 15 kilos (sic) of air for every litre of fuel it burns. Of these 15 kilos, about 20 percent is the proportion of essential oxygen.
Three kilos (which at normal atmospheric pressure would fill a 40ft container). So, for a 50-litre tank of fuel, 150 kilos of compressed oxygen would be needed, plus the weight of its high-pressure steel cylinders. So, the practical answer to that idea is “get real.”
