system
Given the following post, respond as if you're commenting on Reddit:
human
Is a combustion engine more or less efficient when in a cold environment?

In other words, will a cars engine be more fuel efficient when running in a cold or hot environment?
gpt
At wide open throttle it produces power more efficiently in the cold. At partial throttle the engine is fighting the throttle harder than in a warm environment so you end up burning more fuel. This is why race cars have cold air intakes and why hyper-milers often build warm air intakes.