What are possible changes to an engine after a non-software upgrade?

[saviour stivala]

When the specification rules for the 2014 turbocharged engine was finally settled upon, the bore diameter was standardized at 80mm, this automatically also standardized both the stroke at 53mm as well as the stroke/bore ratio at 0.66:1. Also standardized was the max power speed, this was done when the rules added the max RPM at which the max fuel flow was permitted. What was left as free chose was con-rod length and so also the con-rod/crank radius ratio. I do not think that anybody can find any official numbers as regards con-rod length, from pictures/photos (very scarce) of present turbocharged con-rod I have seen my con-rod length calculations hoovers around 130mm con-rod length mark. If my con-rod length calculations are correct the con-rod/crank radius ratio is 4.9:1. This considerably longer con-rod than what was used on the previous NA engines produces less friction and so gives an advantageous efficiency.

[Tommy Cookers]

....This considerably longer con-rod than what was used on the previous NA engines produces less friction and so gives an advantageous efficiency.

not necessarily
remember how high the in-cylinder pressure is on the compression stroke
the compression work in-cylinder is freakishly high

[saviour stivala]

It is precisely the extremely higher ‘in-cylinder’ pressure than that which was used in the previous NA engine formula that pushed engine designers into an engine geometry with a high aspect ratio of con-rod length “higher rod/crank radius ratio”.

[gruntguru]

Not only do these engines have very high peak-cylinder-pressure, supercharged engines typically have a more extended pressure peak. Combining these two factors would suggest the cylinder pressure at maximum con-rod inclination will be extraordinarily high. The result will be extreme piston side-load and the best remedy is a longer connecting rod.

[godlameroso]

Wow I see, thought it was just the 1600cc. The bore must be 80mm. Why is that regulated?

If that wasn't regulated, the teams would likely go for smaller bores and a longer stroke while keeping piston speeds in a sensible range. Longer stroke = more capability to extract energy, at the cost of lower rev limit etc.

Smaller piston faces leak less heat into the head.

If they did, as the 'v' angle is set would it not make a 'taller' engine and rise the c.o.g? (longer crank throw etc?)
It would not seem a good trade off?

Taller engine is determined by deck height, not stroke. You can just use shorter rods to go with the longer stroke, and/or lower the compression on the pistons or make them flatter. Deck height is really determined by the length of the rods plus crank throw.

[Big Tea]

If that wasn't regulated, the teams would likely go for smaller bores and a longer stroke while keeping piston speeds in a sensible range. Longer stroke = more capability to extract energy, at the cost of lower rev limit etc.

Smaller piston faces leak less heat into the head.

If they did, as the 'v' angle is set would it not make a 'taller' engine and rise the c.o.g? (longer crank throw etc?)
It would not seem a good trade off?

Taller engine is determined by deck height, not stroke. You can just use shorter rods to go with the longer stroke, and/or lower the compression on the pistons or make them flatter. Deck height is really determined by the length of the rods plus crank throw.

Would not a longer stroke mean the crank needs more 'space' throughout its motion? IE, if the stroke is increased by 25mm then 25 mm on top and 25mm on the bottom which is 50 mm that has to be accommodated?

Crank ctr 25mm higher (or sump 25mm lower) and 25 mm clearance between the top of the throw and bottom of cylinder liners? I am assuming it is already cut to the limit and the extra can not be accommodated?
(not disagreeing, asking)

[godlameroso]

If they did, as the 'v' angle is set would it not make a 'taller' engine and rise the c.o.g? (longer crank throw etc?)
It would not seem a good trade off?

Taller engine is determined by deck height, not stroke. You can just use shorter rods to go with the longer stroke, and/or lower the compression on the pistons or make them flatter. Deck height is really determined by the length of the rods plus crank throw.

Would not a longer stroke mean the crank needs more 'space' throughout its motion? IE, if the stroke is increased by 25mm then 25 mm on top and 25mm on the bottom which is 50 mm that has to be accommodated?

Crank ctr 25mm higher (or sump 25mm lower) and 25 mm clearance between the top of the throw and bottom of cylinder liners? I am assuming it is already cut to the limit and the extra can not be accommodated?
(not disagreeing, asking)

Again you can play with both rod and crank throw as well as piston thickness to keep deck height identical.

Simple example, Honda's F20c became the F22c with shorter rods, a longer throw crank, and lower compression pistons. The block is exactly the same between the F20 and F22 with the only real change being the crank angle sensor.

F20c crank throw = 87mm F22c crank throw = 91mm F20c has 153mm rods, F22c has 149mm rods. This lowers the rod ratio, and increases mean piston speed which lowers max rpm.

You are right, longer crank throws require more block space, usually the bottom of the sleeve is notched to clear the longer throws. However, longer crank throw doesn't necessarily mean a taller engine, there are ways to clearance the lower block without increasing external dimension.