The tricks up my sleeve... Methods I may implement for better FE.

[trebuchet03]

Originally Posted by omgwtfbyobbq

If the same test compares the same cars, over the same cycle, with the same engine, and (taller) gearing that's favorable in the turbocharged car for fuel efficiency, with the turbo car getting worse mileage than it's NA counterpart with shorter gearing. It's evident that the turbocharged engine is less efficient (over that cycle ) than the NA engine imo. I dunno what else to control for...

That's what I'm getting at... the engine cycles are not the same -- "sameness" means the system model is the same -- turbo charging can be modeled as a reheat stage (something the NA system won't have). I'm not saying that particular setup is or isn't more efficient (because the design determines that and there are plenty of ways to design a turbocharger system) - I am saying that it is a fallacy to make that comparison as a statement of general (or possibly specific to this case) fact.


Hands down, I won't argue that the test shows different fuel economy results reliably. Simply, thermal efficiency is 1 - (heat out)/(heat in). Which is why comparing thermal efficiency of two engines VIA mileage can't happen for engines that have different power ratings (unless adjusted by the ratio of power generated - which is not linear).