DrFranken's Forum Comments
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Mileage trends with amount remaining in tank
In my 06 Prius I can squeeze in just over 10 gallons once the light comes on or about 60 lbs. With all the electronics in the car (and I've added ScanGauge for even more) I reset the MPG at the beginning of every tank and have noted repeatedly that for the last 1/4 tank or so I am able to get the average to go up. I have attributed this to the 50 or so fewer lbs the car is hauling around at that point.
Yes the Prius exibits the same goofy behavior on gauge movement. I know that at one point I went over 300 miles before the gauge moved off FULL. Yah I love good mileage but that's just silly.
In my wife's 2002 the thing goes from 3 bars (of 10) to one bar in about 20 miles. 450 miles on the first 7 bars, 20 on the last 3!
Due to this silliness, I pay no attention to the fuel gauge except if I plan on going a fair distance to judge if I can make without having to stop.
It doesn't need to be this way either. We had a boat for years that held 12 gallons. When full the needle exactly covered the full mark. When it was straight up at half tank exactly 6 gallons would fill it. When the needle perfectly covered the "E" the motor quit, it was quite remarkably accurate. (Yes we always carried spare fuel on the water!)
posted by DrFranken December 1, 2008 at 7:43 PM
Warm Up or No?
Warmup? I'm nearly to the end of my driveway before my engine is even running! OK That's the Prius system making things ready to start while the electric motors roll me toward the road! Truthfully, though, if you don't need heat to defrost/defog the windows put it in gear as soon as it's running smoothly and the oil pressure is up. In any recent car that should be 5 to 10 seconds.
While standing still you get 0.000000 MPG! You should do everything more slowly and smoothly for for the first several minutes until things warm up and this helps shocks, breaks, springs, transmissions and other components too. Certainly your engine will warm much more quickly under the light load of easy driving than it will in idling and you're getting somewhere with the fuel you're burning.
posted by DrFranken December 1, 2008 at 7:15 AM
Synthetic motor oils and MPG
My father, brothers and I began using Amsoil synthetics in the 1970s in everything we own, and we do extend the drain intervals to 1 year. We've used the stuff in everything from 4 Cyl Toyotas to big block GM V8s and in what must be a million miles since then have had zero failures.
We start the synthetic right after break in oil is drained and continue until the vehicle is sold and have several examples of over 200,000 miles with no significant oil consumption (that is no oil added in the 1 year service life). We have tortured the oil with cooling system failures, severe towing, motor-home mountain driving and more.
We also notice the synthetic lubricants in transmissions allow for much easier shifting in cold weather (which was one of the original selling points for us.) While we agree that improved mileage seems minimal, there MUST be some given how much easier things shift and roll.
As a side note their 2 cycle oil runs at twice the ratio of regular oil (100 to 1) cutting smoke from small engines to virtually nil and giving more power too. They couldn't do that if the lubrication factors weren't much better than petroleum based oils.
Wonderful stuff and no, I'm not a dealer, just a happy customer!!
posted by DrFranken December 1, 2008 at 7:05 AM