Engineering Explained

Why Downshifting To Slow Down Is Actually Genius – Engine Braking!

If you've ever driven a manual, you've experienced engine braking: the car actively slowing down when you lift off the throttle. But what's actually happening? With gasoline engines, when you lift off, the throttle valve nearly closes. Now, as the pistons hit their intake stroke, they're trying to pull air against that nearly closed valve, creating a vacuum. That resistance is the main factor slowing your car: the pistons are fighting to draw air through a tiny opening, which slows their motion. Slower pistons, slower engine, and since you're in gear, slower wheels. Engine braking! In a lower gear, like 2nd or 3rd, you slow even more, since the engine spins faster and pulls against that restricted throttle more frequently. And instead of your brakes absorbing the heat, your engine's cooling system handles it easily. It's nothing compared to the combustion heat it already deals with. That's why engine braking is so useful on long downhill stretches. What Is A Jake Brake? - https://youtu.be/o8Cta2cC2Co Subscribe to Engineering Explained for more videos! - https://goo.gl/VZstk7 Recommended Books & Car Products - http://amzn.to/2BrekJm Engineering Explained is a participant in the Amazon Influencer Program. Don't forget to check out my other pages below! Instagram: http://www.instagram.com/engineeringexplained Facebook: http://www.facebook.com/engineeringexplained EE Extra: https://www.youtube.com/channel/UCsrY4q8xGPJQbQ8HPQZn6iA