Quote:
Originally Posted by dremd
In a Nutshell, that BSFC (Brake Specific Fuel Consumption Chart) and all others measure Fuel used at RPM with Max Load
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Not quite dude. The following chart posted earlier by Tas shows fuel consumption from zero load to full load across the entire rpm range. The left axis, BMEP (brake mean effective pressure) is directly related to engine torque. The single line across the top shows the full load engine output, but everything in between that and the x-axis is fuel consumption data at part load. Someone had to take a lot of data points to generate this plot.
Quote:
Originally Posted by tasdrouille
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Dave! Didn't realize this was your project. Always enjoyed your nerd-columns in SCC back in the day. You should be pleased to note that the above BSFC chart is from
your engine, the VW TDI ALH. When you guys get done aero-modding, I would
guess you'll need around 15 HP to maintain 60 mph. If you look between the 10 and 20 HP lines you get an idea how the fuel consumption will be at various engine rpm. As Tas noted, there are dips in the 210, 220 and 230 g/kW-hour BSFC lines at 1250 rpm. This would unquestionably be the optimal engine speed for any load between 10 and 20 HP. But as you stated, who cares, since the gearing is as low as you could get it anyway. You might consider oversizing the tires to help also, which would also fill up the wheel wells a bit more.
I'm basically taking on a tamer version of this same project on my daily driver so its fun to watch your progress. You should have no problem with your goals!