Quote:
Originally Posted by 99metro
Those short trips are killing you. My diesel pickup only gets about 12mpg over 6 miles, yet I can get over 28mpg over 55 miles.
My 99 Metro can just get 40 mpg over 6 miles, but can get over 60 mpg over the same 55 miles.
I believe hypermiling techniques can be realized over longer distances, rather than short trips. Don't idle and let it warm up - just get in, seatbelts on, start it and go. Use light throttle to use the least amount of horsepower. A heavy foot at low RPM is very wasteful.
If you have a Phillips 66 gas station around, I believe most all DO NOT use alcohol/oxygenated fuel (check the pump sticker). Use the lowest octane.
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Do you have proof that high throttle angles at low RPM are wasteful? You've pretty much just contradicted the laws of fluid and thermal dynamics, and the basic theory of engine operation. Those are giant shoes, my friend.
Carb'd or not, the engine will only get enough fuel (given a proper tune) to compensate for the air in the cylinder, which means that at low RPM, using more throttle to reduce pumping losses and make slightly more than normal HP will get you up to cruising speed much faster, with only slightly more fuel being used. It's more efficient that way.
If you've ever accelerated in a manual at 80% throttle, shifting around 2k RPM, and then do the same thing at 25-30% throttle, you'll notice a HUGE difference in the time that you're spending getting from 0-40MPH. Like nearly double the time for the latter, or more.
I'm not going to go through the formulae and do the math for this here, but basically, the engine can only suck in so much air, and by widening the path that it sucks in air through, you're just lessening the vacuum load on the pistons, which means the engine doesn't have to use as much of the generated work (torque) to keep spinning, and has more capacity for moving the vehicle.
In simpler terms - The engine can only produce 100% power per throttle/speed, for the amount of fuel introduced. Of that 100% (Theoretical max), normally, at 30% throttle, 25% of that tM power is being used
just to keep the engine running. By opening the throttle (which acts like a big choke) to 60% the engine can breathe easier, meaning that maybe now only 15% of tM is being used to keep the engine running, leaving 85% tM for moving the vehicle, as opposed to 75%.
(This assumes that tM remains constant based on throttle angle, which just isn't true. You'll get more power if you open the throttle more, except in the case where the engine can't inject any more fuel to match the incoming air - you may lose power in that case.)