I agree friction will always be worse at higher rpm. I don't agree that net power will always peak at 10,500 rpm.WhiteBlue wrote:I don't agree with the power and torque curve. The power will definitely reduce from 10,500 rpm. The friction will cause losses at higher rpms and the combustion efficiency is also likely to suffer.
Manufacturer A decides to design their engine with the goal of maximizing peak power at 10,500 rpm. This means certain levels of boost and compression ratio. The boost, compression ratio, and ignition timing are carefully selected to work together optimally at 10,500 rpm.
Manufacturer B decides to design their engine with the goal of maximizing area under the power curve from 10,500 to 15,000 rpm. This might mean peak power at 12,750 rpm. At this rpm, compared to Manufacturer A at 10,500 rpm, the boost will be lower and therefore the optimum compression ratio would be a bit higher. The boost, compression ratio, and ignition timing will work together optimally at 12,750 rpm. OK, what happens in this same engine at 10,500 rpm? Boost will be higher so therefore the compression ratio will be too high. Detonation will then be a problem so therefore ignition timing will have to be retarded a bit. This retarded ignition might more than cancel out the lower friction at 10,500 rpm. Therefore this engine makes more net power at 12,750 rpm than 10,500 rpm. And it has more area under the power curve to boot.
This is simply one example of how a 2014 engine might not peak at 10,500 rpm.