If you search for any performance vehicle plus “cold start” on YouTube, you’re likely to be served hours and hours of sonorous content. But have you ever wondered why cold starts sound so good?

The answer, covered in this video produced by Hagerty, is that the engine is running as inefficiently as possible in order to get warm itself up. The precise reasons for that have evolved over time, but the basic idea remains the same.

Ironically, the reason that your car sounds like that is because engines are at their worst when they’re cold. Internal combustion engines are designed to run hot, so when they’re cold, the fuel doesn’t burn quite right and there’s more internal resistance.

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Modern cars also have to worry about their catalytic converters, which require heat to work properly. The solution, therefore, is to run the engine more inefficiently for a short time to then allow harmful emissions to be caught sooner. Unless someone has stolen your car’s converter, in which case your car will sound very different than you’re used to.

The result of all of this is that modern cars change their valve and ignition timing to intentionally create heat before returning to their normal engine mapping and running as efficiently as possible. The function isn’t wholly unlike the good old choke valve, but modern cars are much more advanced and hands-off than older cars.

Either way, the result is a sweet, only slightly poisonous, due to the increased emissions, greeting from your car to get you excited for the drive ahead.