Quote:
Originally Posted by CSBM5
According to Steve Dinan (when he gave a talk about S65 Daytona Prototype development), they were getting a bit more power out of the S65 (turning higher rpms of course) from 4.5L vs the 5L DP S62 engine. He did say that since the S65 was smaller and lighter that it was a benefit to engine location and mass if they have to use it. At the time (2010), he hoped that IMSA wasn't going to force them to switch to the S65, but they were ready with an S65 DP design since he believed they would be forced to switch.
It was really interesting (as a mechanical engineer) to listen to him talk about the areas they found power in the S62/S65 engine, especially the discussion about pumping losses where they found huge efficiency improvements (obviously didn't discuss the details). As a side note I asked him about S62 rod bearings, and he said the stock S62 bearings worked fine in the DP engine but of course they rebuild the engines and change them out about every 27 hours of usage  (this was in 2010 when there was an M5board rod bearing panic continually fed by one member trying to make a mountain out of a molehill). |
Long interview on the smoking tire podcast with Steve Dinan where they talk about the S62 and S65 race engine builds: