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I keep reading posts about people getting six and seven hundred miles from a fill-up. The guys on the mileage marathon got almost 1400 miles on a single tank.

Its a good thing that the Prius gas tank is small, or we would need to add Sta-bil! :D
 

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Chris Cording said:
I keep reading posts about people getting six and seven hundred miles from a fill-up. The guys on the mileage marathon got almost 1400 miles on a single tank.

Its a good thing that the Prius gas tank is small, or we would need to add Sta-bil! :D
Chris,

Can you provide a link to the information you are speaking of?

Thanks
 

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I drove 639 miles before I got the blinking pip at 59 MPG displayed. Since I got 83 miles on blinking pip at 52 MPG displayed tank average, I am going for a 700 mile tank.

I figure if my displayed average is 59, my actual can't be much less than 57, though if I get a lot of traffic and hot weather, my trip mileage could be closer to 50.
If my real world tank average MPG is 57, then to go 700 miles I'll need 12.3 gallons. 640 @ 57 yields 11.2 gallons used, so I need 1.1 gallons.
I have done 83 miles on a blinking pip, and I need 61 miles. Close, real close.

Maybe I'll just circle around tonight where there are gas stations within 2 miles when I get to 680 miles. Then again, I might not.
 

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DanMan32 said:
I drove 639 miles before I got the blinking pip at 59 MPG displayed. Since I got 83 miles on blinking pip at 52 MPG displayed tank average, I am going for a 700 mile tank.

I figure if my displayed average is 59, my actual can't be much less than 57, though if I get a lot of traffic and hot weather, my trip mileage could be closer to 50.
If my real world tank average MPG is 57, then to go 700 miles I'll need 12.3 gallons. 640 @ 57 yields 11.2 gallons used, so I need 1.1 gallons.
I have done 83 miles on a blinking pip, and I need 61 miles. Close, real close.

Maybe I'll just circle around tonight where there are gas stations within 2 miles when I get to 680 miles. Then again, I might not.
Don't let Hyperion hear about this type of behaviour.
 

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DanMan32 said:
I drove 639 miles before I got the blinking pip at 59 MPG displayed. Since I got 83 miles on blinking pip at 52 MPG displayed tank average, I am going for a 700 mile tank.

I figure if my displayed average is 59, my actual can't be much less than 57, though if I get a lot of traffic and hot weather, my trip mileage could be closer to 50.
If my real world tank average MPG is 57, then to go 700 miles I'll need 12.3 gallons. 640 @ 57 yields 11.2 gallons used, so I need 1.1 gallons.
I have done 83 miles on a blinking pip, and I need 61 miles. Close, real close.

Maybe I'll just circle around tonight where there are gas stations within 2 miles when I get to 680 miles. Then again, I might not.
Just out of curiosity, what do you attribute your higher than average MPG to? I consistently average between 52 and 54 but never really approach 60. Is it driving 10 MPH under the speed limit or do you have a favorable set of circumstances (temp, terrain, etc.), or is it something else?
 

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I use Sta-bil when mixing fuel for my 2-cycle equipment. I have an older hedge trimmer that I really need to replace one of these days and a chain saw that I use about once a year. Because both devices are only used ocassionally and on a seasonal basis It sometimes takes me a year to go through one gallong of oil mixed gas. I have found that Sta-bil is very good at keeping oil-gas from becoming stale. I can tell when my oil-gas is stale because my 2-cycle equipment is even harder to start than normal.

However, the fuel bladder on the Prius prevents any significant amount of air from being in contact with the gas, along with reducing gas vapor emissions. As such I'm inclined to believe that fuel stored in a Prius tank for over a month would not be subject to nearly as much aging as it would if it was in contact with air, as it is in a portable fuel can or a regular gas tank.
 

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redwein said:
DanMan32 said:
I drove 639 miles before I got the blinking pip at 59 MPG displayed. Since I got 83 miles on blinking pip at 52 MPG displayed tank average, I am going for a 700 mile tank.

I figure if my displayed average is 59, my actual can't be much less than 57, though if I get a lot of traffic and hot weather, my trip mileage could be closer to 50.
If my real world tank average MPG is 57, then to go 700 miles I'll need 12.3 gallons. 640 @ 57 yields 11.2 gallons used, so I need 1.1 gallons.
I have done 83 miles on a blinking pip, and I need 61 miles. Close, real close.

Maybe I'll just circle around tonight where there are gas stations within 2 miles when I get to 680 miles. Then again, I might not.
Just out of curiosity, what do you attribute your higher than average MPG to? I consistently average between 52 and 54 but never really approach 60. Is it driving 10 MPH under the speed limit or do you have a favorable set of circumstances (temp, terrain, etc.), or is it something else?
My trip consists mostly of driving 48 miles one way on US19. Average speed is 45, but speed limit goes from 45-55 with lights averaging about 5 miles apart. Tires at 40F/38R, this time I had the oil filled to 3.5 quarts so it is just under full. Weather has gotten a bit cooler. At least there's less solar radiation. Going home, the mileage is harder, as the AC tries to cool the cabin down and combat solar radiation, and traffic in the beginning is slower due to construction of overpasses.

I DID IT! 701 miles. Looking at my notes though, I have done 716 on July 3rd. When I got near home, I had 690 miles, so I drove around between gas stations that were 2 miles apart, staying near the last suitable gas station before getting home.
 

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DanMan32 said:
My trip consists mostly of driving 48 miles one way on US19. Average speed is 45, but speed limit goes from 45-55 with lights averaging about 5 miles apart. Tires at 40F/38R, this time I had the oil filled to 3.5 quarts so it is just under full. Weather has gotten a bit cooler. At least there's less solar radiation. Going home, the mileage is harder, as the AC tries to cool the cabin down and combat solar radiation, and traffic in the beginning is slower due to construction of overpasses.

I DID IT! 701 miles. Looking at my notes though, I have done 716 on July 3rd. When I got near home, I had 690 miles, so I drove around between gas stations that were 2 miles apart, staying near the last suitable gas station before getting home.
Thanks for the info. I think the speed is probably the most important factor. The best stretch I got on my cross country trip was on roads similar to what you describe. I drive the freeway at 65 every day for about 80 miles round trip. I think I'm pretty much limited to the low 50s.
 

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Discussion Starter #11
Stabil joke

It is possible to get close to 60 mpg with higher speeds. I drive 32 miles on 70 mph Interstate, and 20 miles on 55 mph road each day. The key is:

1) Driving technique - triggering the "glide" mode (no arrows) down hill and when stopping for traffic lights. Slow acceleration. Anticipatory stopping, etc.
2) No A/C (really detracts from mpg). Don't believe the old wives tale that opening the windows creates more drag and lower mpg than A/C.
3) High tire pressure (52 front/48 back). Yes, I know the max cold inflation pressure is 44 mpg. Do it at your own risk!

The main thing is to enjoy your car. If trying for extra high gas mileage is your thing, then go for it. But if you enjoy more normal driving, then you will still get great gas mileage. :D
 

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Re: Windows vs AC

Chris Cording said:
2) No A/C (really detracts from mpg). Don't believe the old wives tale that opening the windows creates more drag and lower mpg than A/C.
It's not an "old wives tale". It's a measurable scientific fact. Above a certain speed, the additional drag from having the windows open would sap more energy than running the AC. It would vary based on how far you had the windows open and how high you have to crank the AC. I would like to see the results of a good experiment with a Prius comparing running the AC vs having the windows down a reasonable amount at various speeds and at various outside temperatures.
 

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Not additives, driving style

I was watching Top Gear on TV the other night, and the host drove 800 miles in an Audi diesel (A8). Averaged 40 mpg. Audi told him it was not possible to do this. What he did was drive steadily, never used his breaks, had all the windows up, emptied the car of everything. Also, he used the heat only a few times. He also said to fill up in the cooler weather because gas is more "dense." (I don't know about that)

Essentially, it was a lesson on how to get the most mpg while driving. One thing stuck out, having the windows down decreases mpg by 3 or 5 % - I can't remember which one.

One interesting thing was that when he was driving with the cruise control, he was averaging fewer mpg's than when he was diriving without it. He just drove very carefully, with a light foot.

I guess with the price of gas in the UK, maybe here too in the future, these are all good tips to know.
 

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My experience says that driving with the AC uses more fuel than driving with the windows down. However, the times you would be willing to drive with the windows down are the times the AC would not need to work so hard.
The true test would be taking 2 prius, drive them side/side. One with AC on, one with windows down. Otherwise, there are just too many variables that are difficult to control that change with different times.

I agree that you probably can get more gas in the tank when its cooler, but I believe it is because you have more gas vapors in the tank that make it more difficult to get more liquid gas in without tripping the auto-shuttoff.
 

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DanMan32 said:
My experience says that driving with the AC uses more fuel than driving with the windows down. However, the times you would be willing to drive with the windows down are the times the AC would not need to work so hard.
The true test would be taking 2 prius, drive them side/side. One with AC on, one with windows down. Otherwise, there are just too many variables that are difficult to control that change with different times.

I agree that you probably can get more gas in the tank when its cooler, but I believe it is because you have more gas vapors in the tank that make it more difficult to get more liquid gas in without tripping the auto-shuttoff.
I think having the windows down can cost you MPG at higher speeds, such as freeway and above. I think at below that, it probably doesn't affect it much.
 

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Discussion Starter #16
A/C vs windows

Re: A/C vs rolling down the windows:

MikeFromEastCoast writes:
"It's not an "old wives tale". It's a measurable scientific fact. Above a certain speed, the additional drag from having the windows open would sap more energy than running the AC. It would vary based on how far you had the windows open and how high you have to crank the AC. I would like to see the results of a good experiment with a Prius comparing running the AC vs having the windows down a reasonable amount at various speeds and at various outside temperatures."

An automotive engineering professor gave me and another engineer the project to prove or disprove the old canard about better mpg with air-conditioning vs rolling down the windows. We tested a Volkswagen Beetle (only two windows). The results were not even in the same order of magnitude. A/C is an energy hog compared to opening the windows. Opening both doors and holding them straight out was almost equivalent to the A/C at 50 mph. Of course, the results are a sliding scale of compressor cycle time, driving speed, etc. And the Prius air conditioner is more efficient than most auto A/C systems.

If you are a mileage junkie, experience will teach you that heavy use of A/C will hammer your gas mileage. You won't find anyone who posts how they got really great gas mileage by running the A/C all the time. You will find plenty of posts of people hitting records (such as 1397 miles on a tank in a mileage marathon) by not using A/C (among other tricks).

To give some perspective on A/C energy use, the A/C will drain the battery in about 10 to 20 minutes on a hot day with the car parked. The battery is capable of driving the car about 2 miles from "green bars" to "pink bars." The A/C is using the equivalent energy of driving 6 to 12 miles every hour. Thats a lot of energy! Opening the windows in the side slipstream of air is not a very big drag force.

I just broke 600 miles on a tank for the first time (never really tried before). 626 miles at 57.6 mpg. Of course, DanMan32 beat that handily with his 700 mile range.

Some other posts have interesting information on this matter:

http://priuschat.com/forums/archive/o_t ... index.html

http://www.priusonline.com/viewtopic.php?p=10376
 

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Yup. 600+ MPG is a regular occurance for me.

Got to get gas on the way home today. Car beeped with blinking pip at about 618 miles with 61MPG on the display. Guess I didn't pack as much fuel as I could have last fill up.

I have someone I am carpooling with, so I don't want to freak him out going for 700 miles again. It's bad enough he heard the Add Fuel beep.
 

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:oops: Er, I Meant 600+ miles per tank. Change that G to a T.

At 600MPG, the gas would probably go bad before I could finish a tank!
 
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