Originally Posted by janvanvurpa
Wait a second! Air flow, or air volume into the turbocharger is limited sure, but what happens to whatever air manages to get into the turbo isn't. Air FLOW is only part of the story and the other half is what is done in the cylinder and the head: compression. More compression means a bigger "bang" or maybe "pang!" på finska. Two things limit how big the Pang! is: the fuel resistance to detonation and the distance the flame front must travel.
Fuel is set, so the resistance to detonation comes down to things like cylinder diameter. WRC engine builders i talk to say engines with smaller bores like the old Mistusishi or others around 85mm bore are much more tolerant of higher static compression than motors with larger bore like YB Cosworth at 90,8mm or Subaru at 92mm...
I would guess the new 1600s will be somewhere around 80 to 81mm bore, sound small, and tolerant.
Just make the cylinder walls 6mm thick and the rods like little stumpy rods and a good steel crank and you have a good bottom end that will make a good amount of 'vrid moment' or as i call it 'yank' or 'ax' or PANG!
Then with right box and final drive it should go really well.
We can't look back to the old Mazda GpA car with it's 1600 because the basic motor was a undersized piece of junk from the beginning, very small parts in the crank and rods....