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Gas combustion engines at elevation

Gas combustion engines may not be the best solution for every application

It is commonly known that small CFM gas driven air compressors don’t perform as well at 5,000 feet of elevation as they do at sea level. They may stall out, bog down or supply less air power. However, it’s not as commonly understood why this happens.

It all comes down to the physics of the gas combustion engine.

As elevation increases, air density decreases. As air density decreases, the amount of available oxygen for combustion decreases. Combustion takes place when fuel reacts with oxygen and an ignition source.

As the amount of available oxygen decreases, the engine must work harder to meet demand. Eventually, the rate at which combustion burns oxygen outstrips demand and the engine starts to bog down or even stall. With the rise in elevation and the resulting decrease in air density, there is a proportional decrease in horsepower that the engine can produce.

Larger engines do not often experience this issue because there is more available horsepower for auxiliary equipment.

Small combustion engines like those found in standalone gas driven air compressors, generators, and pumps are susceptible to experiencing this performance issue at elevation.

This includes the VMAC G30 gas drive rotary screw air compressor . Though field testing shows that the G30 will provide full air output at over 5,000 feet of elevation, as with any gas engine this is dependent on ambient temperature and humidity. Operators running the equipment in areas of frequent high temperature and humidity may experience performance issues above 3,500 feet of elevation. For applications in these conditions at higher elevations there may be a better solution than a standalone gas drive compressor.

VMAC products designed for applications at high elevation include:

To learn more about how elevation affects air compressors, read our recent blog post.

If you have any questions about this article or anything mobile compressor related, please contact us.