Originally posted by InitialD
I don't think so... Short rod engines are suppose to be better at the top end.
Anyway, I actually physically measured the Sirio conrod. Their lenghts are actually the same as the Collari engines (Picco based). The only difference was the bushing hole was bigger. I would think that since Dennis once categorised the Collari as a mid rod engine, the Sirio should also fall into the same category. Neither short nor long
Sorry to pinch your bubble, but....
Anyone told you that the stroke of an engine SHOULDN'T be measured by measuring the conrod? should be measured by the radius from the center of the crank to the center of the conrod pin (as did on full size engines), multiply by 2 those measurement and you will get the stroke of an engine with this crank....
If an engine is a short rod or a long rod shouldn't mean anything about their performance. You can have an engine with a 13mm stroke and a conrod of 30mm and their stroke still be 13mm, not 30.
Conrod lenght affects to other parameters... (linear velocity of the piston at different angles of the crank, dwell time and others like side loads applied to the piston sides but never tell you where should be located their power curve).