Never Use This Gas In Your Car!

Summary by Krater

This video explains why low-octane fuel (such as 85 octane) is sometimes sold at high elevations, how elevation affects barometric pressure and engine knock, and why older carbureted engines tolerate low-octane fuel at elevation while modern vehicles with electronic fuel injection and turbochargers do not.

From the video

Answers: Why is 85 octane fuel sold at high elevations, and can you use it in modern cars?

• engine knock
• octane rating
• barometric pressure at elevation
• carbureted vs modern engines
• ignition timing and air-fuel ratio

What it concludes

• Low-octane fuel (like 85 octane) sold at high elevations can cause engine damage in modern cars that is not covered by the vehicle warranty.
• Older carbureted engines experienced a drop in octane requirements at higher elevations, making 85 octane fuel safe and cost-effective for them.
• Modern vehicles with electronic fuel injection, electronic ignition timing, and turbochargers or superchargers do not experience a significant drop in octane requirements at elevation up to about 3,300 feet.
• Using 85 octane fuel in modern cars at high elevation risks engine knock, especially under heavy load or when towing a trailer.
• Manufacturers recommend using premium fuel with an octane rating of 91 or higher when towing a trailer or driving in hot weather.