PlatinumZealot wrote:Another thing to consider is piston clearance.
F1 engines are so tight they can barely be turned at room temperature. The surface finish on the cylinder walls are like a robot baby's bottom so imagine the microscropic gap around the piston. The BMEP of F1 engines are big, but so is the piston bore. The CSA of the gap is extremely small compared to the bore.
broadly speaking .... with recent N/A F1 (extreme bore:stroke ratio of about 2.5, and extreme piston acceleration and rpm)
the piston is tight at room temperature primarily because it is made out-of-round
this because the piston is minimised to a pin boss structurally integrated (conceptually, flush) with the crown
because it's structurally far from symmetrical, so its expansion is far from symmetrical
the parts of the piston carrying the rings are a minimally small proportion
none of this need apply currently as the b:s ratio (about 1.6) , and rpm and minimum engine height are conservative/traditional
imo