Quote:
Originally Posted by DGthe3
The cost is part of it though. And with naturally aspirated engines, there is a big difference between a small engine with a high specific output vs a large engine with low specific output even if both make the same peak power. Namely torque, powerband, and average output.
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You have to take "effective" displacement into account. Displacement is literally the volume of the fuel/air mixture in the combustion chamber. When you increase pressure without increasing volume, you are
effectively increasing displacement. Because of many factors like heat radiation, this is not an exact truth, but in theory a 2.0L engine boosted to 14.7PSI above atmospheric or +1 ATM is effectively a 4.0L engine. There isn't a replacement for displacement, but there is a replacement for physical size of the combustion chamber and that is pressure.
Anyway since that example is fresh in your head, mean effective pressure is just as important as volume of the combustion chamber. Really, MEP itself is the explanation of how Ford can make such power with such displacement and I am shocked it hasn't been thoroughly discussed in this thread. Actually, I am not LOL.
simply put:
Work done = mean effective pressure * displacement
You then have to account for number of cycles (RPM), but you get the point.
Work is what really matters.
If something above doesn't make sense or is miswritten I apologize and I will fix it in the morning. My laptop is just about to run out of batteries and I don't have time to look it over.