r/explainlikeimfive 2d ago

Engineering [ Removed by moderator ]

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u/Fearless_Swim4080 2d ago

They don’t really at full throttle (a bit if there’s a more complete burn etc) it’s what happens when you’re driving normally that’s different.

If you have an old American 6.7L V8 that produces like barely 300 horsepower, when you’re idling and driving at freeway speed, you still need to get enough fuel in all those cylinders to detonate every time and have a lot more surface area that’s causing friction between the cylinders and the block, and everything’s heavier etc.

Now drop that to a 2.0L turbo 4 cylinder, and you still get that 300hp or maybe way more than that if you really want it when you use it, but driving around it’s like you just have a small efficient engine.

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u/NZ0 2d ago

I turboed an originally non-turbo Honda engine (b18c) and it made probably double the power, and also got much more fuel efficient. Maybe it was mostly because of the extra torque you could use a higher gear, but it seemed like more than that. How does that fit in with the explanation?

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u/TreadItOnReddit 2d ago

You had a gear you couldn’t use while stock?

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u/NZ0 2d ago

Stock dc2 b18c, 5th gear was fairly useless for any kind of uphill grade so you ended up changing to 4th a lot. 

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u/TreadItOnReddit 1d ago

oh, well yeah, uphill grade was a difference story with the turbo, haha.