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Longsnowsm · 07-22-2015, 01:10 PM

Time isn't a factor if your objective is ultimate efficiency, maximum MPG. If maximum MPG is the focus then you have to set time aside and focus on that objective. If however you live in a world where you are willing to compromise some efficiency to account for time and the maximum rate of return for both time and fuel economy then there is some math involved and understanding your own vehicle. Only you can decide what your objective is.

My position on this is there is a break point where you cannot go any faster or push any harder without going to far and breaking the return on your investment regardless if that is in time or fuel.

For example if I get 50 mpg at 30mph, 45 mpg and at 40 mph, 40 mpg at 50 mph, 30mpg at 60mph, 20mpg and 70 mph you then have to decide do you have time to invest or fuel and if so how much? Your best bet unless you happen to have a lot of time on your hands or a lot of fuel budget is going to be someplace in the middle to try to maximize the most of both time and fuel your investing in the trip.

Of course it isn't that simple and there are lots of other factors like weather, temps, wind speed and direction, hills, elevation, the ability to get a "ride" and draft, vehicle, aero profile, and mods you have made... and last but not least the loose nut between the seat and the controls of the vehicle.

Good instrumentation is the key to all of it, if you don't know what is happening real time then it is really hard to make the proper adjustments when your waiting to fill up the tank to know just how things are going.

So if maximum fuel economy is your goal then I will agree time has to be set aside as a factor. If however your trying to figure out how to split the difference between time and fuel then you need good instrumentation, and the willingness to learn where the sweet spot is for your vehicle and the routes your taking.

The other time factor is how frequently your having to stop. If you have to stop every 200 miles to fill up and it takes 15-20 minutes to get gas and get back on the road then that is an additional 15-20 miles you can be down the road and if you have to repeat that cycle several times you just added a significant amount of time to the trip. If by slowing down you can make fewer stops your saving that time. Now if your going so slow that even that time savings from not having to stop doesn't matter then again you are probably focusing(or should be focusing on maximum MPG and not time). But if your weighing both time and fuel then if you can go longer, not have to stop even one or two additional times the time lost by going slightly slower is made up in making fewer stops. In the end if you play your cards right you will not have added a huge amount of time to your trip, but obtained respectable fuel economy in the process.

Longsnowsm

07-22-2015, 01:10 PM	#10 (permalink)
Longsnowsm EcoModding Lurker Join Date: Apr 2011 Location: US Posts: 70 Peaty - '03 Honda Insight Jimmy - '07 GMC Canyon 2wd, Extended Cab, SL Thanks: 22 Thanked 12 Times in 9 Posts	Time isn't a factor if your objective is ultimate efficiency, maximum MPG. If maximum MPG is the focus then you have to set time aside and focus on that objective. If however you live in a world where you are willing to compromise some efficiency to account for time and the maximum rate of return for both time and fuel economy then there is some math involved and understanding your own vehicle. Only you can decide what your objective is. My position on this is there is a break point where you cannot go any faster or push any harder without going to far and breaking the return on your investment regardless if that is in time or fuel. For example if I get 50 mpg at 30mph, 45 mpg and at 40 mph, 40 mpg at 50 mph, 30mpg at 60mph, 20mpg and 70 mph you then have to decide do you have time to invest or fuel and if so how much? Your best bet unless you happen to have a lot of time on your hands or a lot of fuel budget is going to be someplace in the middle to try to maximize the most of both time and fuel your investing in the trip. Of course it isn't that simple and there are lots of other factors like weather, temps, wind speed and direction, hills, elevation, the ability to get a "ride" and draft, vehicle, aero profile, and mods you have made... and last but not least the loose nut between the seat and the controls of the vehicle. Good instrumentation is the key to all of it, if you don't know what is happening real time then it is really hard to make the proper adjustments when your waiting to fill up the tank to know just how things are going. So if maximum fuel economy is your goal then I will agree time has to be set aside as a factor. If however your trying to figure out how to split the difference between time and fuel then you need good instrumentation, and the willingness to learn where the sweet spot is for your vehicle and the routes your taking. The other time factor is how frequently your having to stop. If you have to stop every 200 miles to fill up and it takes 15-20 minutes to get gas and get back on the road then that is an additional 15-20 miles you can be down the road and if you have to repeat that cycle several times you just added a significant amount of time to the trip. If by slowing down you can make fewer stops your saving that time. Now if your going so slow that even that time savings from not having to stop doesn't matter then again you are probably focusing(or should be focusing on maximum MPG and not time). But if your weighing both time and fuel then if you can go longer, not have to stop even one or two additional times the time lost by going slightly slower is made up in making fewer stops. In the end if you play your cards right you will not have added a huge amount of time to your trip, but obtained respectable fuel economy in the process. Longsnowsm Last edited by Longsnowsm; 07-22-2015 at 01:22 PM..