Duffman, I have serch in my memory
The pic posted by me, it is a comparation of extimated fuel consumption between the same engine with throttle operation and WOT, the dashed line is the BSFC reduced by throttle loss.
Bottom axis, is the engine RPM; that one written in Italian isnt' relevant.
Note, the discendent curve of the dashed line from 1000 to 5000RPM...I think that is caonsequently of reverse flow in the intake runners and loss of air intake through the exhaust because overlap cams