MadBill wrote: ↑Wed Mar 31, 2021 12:25 am
Speaking of tough, I'm finding it challenging to parse that reply...
Diverging a bit, the slow drift down in VE with increasing revs indicates that nothing (head, intake, exhaust) has run up against a brick wall, there is more to be had at higher revs with the right changes using essentially the same equipment (i.e. same head).
The engine could be making more torque by improving the combustion. More power by improving cylinder filling at yet higher revs plus the added improved combustion. Conservatively 5% on combustion and 10% on revs as a start, so about 5 % more peak torque and 15% more peak power. Mind you the internals then need to be OK at 8800 rpm plus some amount of overrev, instead of 8000 rpm plus some amount of overrev.
One could always change the head too, but quite often that is either not desirable (cost), or not possible (rules), or might result in a narrow powerband engine (OK for some things and not OK for others).