Originally Posted by
Karl
I genuinely can't comment with certainty about the WRC engine configuration as I don't know what their development issues were. Development it usually necessary due to issues found during testing that were not forseen during the design stages. Whilst many would wrongly assume that increasing rod length was for a power gain, I would suggest it was more a function of reducing bore deformation due to the higher compression ratios, 102 ron fuel and high cylinder pressures used to optimise the engines restricted power output.
I would speculate that the reason they started to use long rods was not for reasons of best power output (because as Ive allready said a lower rod ratio gives best bottom end torque) but because it was a means to an ends for making the engine more reliable. This is not something that applies to the average cosworth owner because bore distortion is'nt actually an issue for what Id deem a conventional cosworth spec engine running on pump fuel.
I agree what you say there probably makes sense but i can assure you as iv used them now on a couple of engines that they make great torque and hold on to the torque longer in the rev range..
I had a 530 hp motor that had ruined its bottom end after a good life and put the whole top end on to a long rod short piston bottom end and then re dyno and we found that it made better torque and held on to the torque just over a 1k more up the rev range and peak power was a little later too..
I under stand the higher cr would of helped also but it was just a better engine after this in every way..
I can say after seeing them in use on a few engines too that the bore wear is deffo better and imo is a worth while upgrade still..
cheers danny