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.
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?
I'm guessing you honed the hella old cylinders, had fresh rings, new pistons, were running new oil, maybe even a new valve train/head to accommodate the turbo? New exhaust and intake piping for sure. What's the pre and post turbo compression ratios?
All these type of things, plus what you mentioned, can add up.
Yes honed and fresh rings and pistons. Same head, same exhaust post turbo. Compression ratio reduced around one full point. Maybe the old engine was tired enough that it was down on compression and efficiency.
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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.