Interesting MPG...
#1
11-16-2003, 10:15 AM
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Interesting MPG...
So I made a quick trip from Washington DC out to the Eastern shore of MD (about 70 miles) and did a quick MPG survey. Going out, I drove 65 the whole way and averaged 18.6 MPG - a great number. Going back, I increased the speed to about 72 the whole way, and I got 17.2
This isn't a huge difference, but it is very interesting to me an extra 100-150 RPM decreases the MPG so noticably. Anyone else notice similar things? Perhaps when my engine is broken in better, this will go away?
This isn't a huge difference, but it is very interesting to me an extra 100-150 RPM decreases the MPG so noticably. Anyone else notice similar things? Perhaps when my engine is broken in better, this will go away?
#3
11-16-2003, 10:43 AM
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#4
11-16-2003, 10:43 AM
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Its about 7.5% difference however it’s not really a good indication of the actual fuel mileage you’re getting.
The best way to calculate your fuel mileage is tracking multiple tank fills. You could start with 5 tank fill ups. Each time you fill up you do you normal calculations and after 5 fill ups you average them. Obviously you’re not going to be able to do 5 tanks and always drive at 60mph, and then another 5 tanks and 72mph.
If you did you would get an actual representation of the fuel mileage at different speeds. For one the higher speed will indeed take more fuel to travel the same distance if you had driven a slower speed. The higher the speed the more resistance the road and wind provide. To overcome the increased resistance the more horsepower that is needed, more horsepower equals more fuel.
When you drove one way at 60mph you could have had the wind at your back, could have been driving down a slight incline. Coming back at 72mph you could have had head winds or side winds, could have driven on up a slight incline maybe not enough to notice but it takes very little to create resistance.
In either case even driving 200 miles is no where enough to give you a proper indication of your “true” fuel mileage.
If you drive down a straight and level road one day with a tank full and it is calm with no wind you will get a lot better fuel mileage then if you had drove it with a lot of wind, head wind or side wind.
Just something to keep in mind…
The best way to calculate your fuel mileage is tracking multiple tank fills. You could start with 5 tank fill ups. Each time you fill up you do you normal calculations and after 5 fill ups you average them. Obviously you’re not going to be able to do 5 tanks and always drive at 60mph, and then another 5 tanks and 72mph.
If you did you would get an actual representation of the fuel mileage at different speeds. For one the higher speed will indeed take more fuel to travel the same distance if you had driven a slower speed. The higher the speed the more resistance the road and wind provide. To overcome the increased resistance the more horsepower that is needed, more horsepower equals more fuel.
When you drove one way at 60mph you could have had the wind at your back, could have been driving down a slight incline. Coming back at 72mph you could have had head winds or side winds, could have driven on up a slight incline maybe not enough to notice but it takes very little to create resistance.
In either case even driving 200 miles is no where enough to give you a proper indication of your “true” fuel mileage.
If you drive down a straight and level road one day with a tank full and it is calm with no wind you will get a lot better fuel mileage then if you had drove it with a lot of wind, head wind or side wind.
Just something to keep in mind…
#5
11-16-2003, 10:52 AM
