http://www.chevyhiperformance.com/te...s/0508ch_carb/
Here is a link to a large american engine (A pushrod 5.7L LS1 with a carburetor! tuned to 519hp giving it 91HP/L) that shows a number of BSFC ratings where the lowest is listed as 0.382lbs/hp/hr.

And in this interesting paper: http://www.itepsa.com/samples/SIET199907_CH1_MAIN.PDF
it says that the best the Honda F20C can do is 378g/kWh so knowing that 1g/kWh = 0.00164398681lbs/hp/hr then the F20C is only good for 0.621lbs/hp/hr or roughly 63% more fuel used. And that is on a little 2L DOHC engine with high tech materials and a massive 120HP/L rating. Do you believe me now?

Oh and you can compare diesel and gas burning engines with only the BSFC number because diesel fuel weighs more than does gasoline per volume but its energy density is approximately the same. That makes it possible to compare the relative efficiencies of gasoline vs. diesel engines simply by comparing their BSFC numbers.

[QUOTE name=KnifeEdge_2K1]if it only processes 1.5x the amount of air then it becomes volumetrically inefficient leading to more pumping losses and thus less efficient, an engine's job is to pump as much air possible as quickly as possible, a 4L engine has the capacity to pump twice as much air in the same amount of time as a 2L engine, if it only pumps 3L of air then there is potential not being tapped, that to me is inefficient[/QUOTE]

Yes the volumetric efficiency is lower but that doesn't always mean that it has to work harder. You forget that if the engine is only moving 3L of air than that takes less energy than if it needed to move 4L of air. Most stock car engines are lucky if they reach 80% volumetric efficiency even though most engines are capable of over 150% with FI.

[QUOTE name=KnifeEdge_2K1]and i have explained to you 3 times why a low specific output engine is inefficient compared to a high specific output engine of similar design[/QUOTE] Funny I thought you where trying to show that lower tech american engines where less efficient than their high tech (not so similar) brothers. Also your explainations don't hold water and simply are not true and I think that you will see that by the end of this post.

[QUOTE name=KnifeEdge_2K1]your example was a specific example and doesnt hold true for all cases, mine is general and DOES apply to all cases with my stated restrictions, all you proved was that your engine A is less efficient then engine B, and would only hold true for engines with the same stats as A and B, you cant do inductive reasoning in this case[/QUOTE]
You missed the point of my example. You keep saying that your statement that engines with higher HP/L ratings are always more efficient than engines with lower HP/L ratings is general and is always true but I showed through a single valid example that this is not the case. I have now posted further valid proof that even though an engine has a higher HP/L rating it is not the most efficient (and in most cases is actually most likely to be the least efficient in a comparison). I have tried to tell you about the many other reasons why looking at the specific output measurement of HP/L will not tell you anything about efficiency but you don't seem to care?

So now you know: HP/L has nothing to do with efficiency OK!