Numerous joker updates on the first generation cars seemed to make sod all difference.
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I think that they still have relative disadvantage in used stock base engine even though it went through a lot of changes since the time DS3 was developed. I mean that they are still the only ones using stock 1.6 engine as a basis and therefore near stock bore/stroke ratio which is a lot different than in other cars (they have smaller bore and larger stroke).
Does this make sense: http://www.carmag.co.za/technical_po...s-shortstroke/
So for rally the longstroke gives a bit more torque in low revs, is that the main advantage?
in the two litre era they used to be square did they not?
I thought the modern turbos compensated for this.
I am not engine engineer but if I remember the main issue with such small bore engines is that the piston is so small that there is not enough space for larger valves. For sure there is a reason why purpose-built WRC engines have large bore and short stroke - Polo WRC bore/stroke ratio 1,125; Fiesta WRC 1,123; C3 WRC 1,167. Now compare with same size R5 units. Fabia R5 1,088 (based on 1.8 stock engine with shortened stroke); Fiesta R5 1,192 (based on 2.0 stock engine with shortened stroke); C3 R5 0,897 (based on stock 1.6 engine).