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Originally Posted by Kinzer S13GT
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This cylinder head design, is superior to the 1st gen S63. And the engine as a whole, is worlds apart from the outgoing S85. (not to say its a poorly designed engine, lol! BMW PTG can make 800+hp on a naturally aspirated S85 ) This engine is just doing so much more to move more air, and more (or less) fuel, to make power twice as efficiently as that engine. Actually as far as volumetric efficiency is concerned, its probably running at an average of 75-85% of its max potential volumetric efficiency. Depending on conditions. Whereas the S85 was sitting around 40-60%! BMW builds the most ridiculous engines, then dials their output down to 5' before selling it to us civilians! Their capabilities are always underrated!
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Your comments on volumetric efficiency are either incorrect or poorly stated. VE is a function of rpm at a given throttle (typically tested/calculated at WOT). Thus folks typically refer to peak VE as "VE" or supply a rpm dependent curve. Thus there is not really an "average" VE except perhaps a time averaged one specific to how each driver might be driving. So if you are claiming the S85, a wonderful breathing machine, can only hit a (peak) VE of 60% that is absurdity. Even the "lowly" Z3 M Coupe can reach over 100% peak VE. Although I do not have the data handy, I am positive that the S85 (and thus S65) also reach over 100% peak VE. Comparing VE across FI and NA engines is pretty well meaningless just like comparing hp/l for FI vs. NA is.