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Originally Posted by BHarvey
So, since the new UG has HP, torque and kilowatts, could you combine those with VE, Load, and whatever other gauge and map it?
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The HP is an approximation. The torque is also an approximation. Ditto the kilowatts (which is power just like HP, but in a different scale). VE is somewhere between an approximation and a wild guess.
Using those to calculate BSFC means you will have numbers with several sets of approximations all multiplied together. The results will be little if any better than picking numbers out of a hat, sad to say.
Quote:
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Originally Posted by jdchmiel
If you have a fast sampling rate, you should be able to calculate it from logging the engine sensors through the OBD2 port.
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That's exactly what the UG does. I think the "fast" sampling rate available is about 1/second, which isn't very fast for a gauge. The consumption figures that it shows you are approximations, every single one of them. No car that I know of (except possibly some very specialized and $$$$ test cars) measures fuel flow into and out of the fuel tank. So you get estimates of fuel used based on the amount of time the injector is open, and (if you're lucky) some notion of the fuel pressure versus the manifold pressure. And maybe a fudge factor for the amount of time it takes to open and close the injector itself. Still an approximation.
And the engine management system doesn't know the exact amount of torque or HP that it is producing at any time. There aren't any sensors that provide that information. It may be able to guess, using the vehicle speed and a time counter, and some guess as to the current weight of the car and current traction available and air density and so on, but that's an approximation of an approximation.
So again, you've got graphs of things approximated by multiplying approximations, plotted against things approximated from guesses.
It would take a decent amount of work to get results, and the results would be about a half-step better than random noise.
IMHO. (Well, not
that humble!)
-soD