EcoModder Forum A new idea for better FE at the pump - literally

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 01-21-2012, 04:16 AM #2 (permalink) Enthusiastic EcoModder   Join Date: Dec 2010 Location: San Diego Posts: 90 Gnatmobile - '96 Geo Metro LSI 90 day: 44.68 mpg (US) theRAV - '01 Toyota RAV4 NV 90 day: 21.07 mpg (US) ACCELICA - '95 Toyota Celica GT Convertible Last 3: 23.46 mpg (US) The Van - '05 Chevrolet Uplander LS LWB 90 day: 21.04 mpg (US) Thanks: 4 Thanked 31 Times in 12 Posts Math is not my strong suit, does the following sound correct more or less? Let's say my range is 400 miles on my 8 gallon tank (which it often is). Let's say gas weighs roughly 8# per gallon. If I do 400 miles I would imagine I carry on average 4 gallons or 32# of fuel. Now lets say I do a half fillup. This would allow me another 200 miles carrying an average of 2 gallons or 16# of fuel. For the combined trip I would have been carrying 32#s 66% of the time and 16#s 34% of the time. By my calculations that's 600 miles carrying an average of 26.5#s of fuel. 32-26.5=5.5#s saved. Not the most impressive ever, but think about bigger tanks, or if you did this for an extended period of time with multiple one or two gallon fills. Food for thought... __________________ "You too can get 50 Miles per Gallon, all it will cost is your self-respect."
 01-21-2012, 04:36 AM #3 (permalink) (:     Join Date: Jan 2008 Location: up north Posts: 12,761 Blue - '93 Ford Tempo Last 3: 27.29 mpg (US) F150 - '94 Ford F150 XLT 4x4 90 day: 18.5 mpg (US) Sport Coupe - '92 Ford Tempo GL Last 3: 69.62 mpg (US) ShWing! - '82 honda gold wing Interstate 90 day: 33.65 mpg (US) Moon Unit - '98 Mercury Sable LX Wagon 90 day: 21.24 mpg (US) Thanks: 1,584 Thanked 3,546 Times in 2,215 Posts Instead of guessing how much gas weighs, why don't you google it? In addition, I know I've posted about "gas tank games" before... are you figuring in the extra stops, extra un-cappings of the tank, extra engine starts, extra accelerations and brakings, and general extra farting around by stopping for gas in small quantities? __________________
 01-21-2012, 05:49 AM #4 (permalink) Eco-ventor     Join Date: Oct 2010 Location: sweden Posts: 1,501 Princess - '92 Mazda MX-3 GS House of TudorTeam Mazda 90 day: 53.54 mpg (US) Shirubāarō (*´ω｀*) - '05 Toyota Prius Executive Team Toyota 90 day: 53.13 mpg (US) Thanks: 64 Thanked 607 Times in 384 Posts I had a similar idea, but with jerry cans. U'd fill them up when you filled your car at the pump, then u'd take them out of the car when you got home. Now you could keep filling your car the minimum without making extra stops. But yeah.. __________________ 2016: 128.75L for 1875.00km => 6.87L/100km (34.3MPG US) 2017: 209.14L for 4244.00km => 4.93L/100km (47.7MPG US)
 01-21-2012, 06:42 PM #5 (permalink) Enthusiastic EcoModder   Join Date: Dec 2010 Location: San Diego Posts: 90 Gnatmobile - '96 Geo Metro LSI 90 day: 44.68 mpg (US) theRAV - '01 Toyota RAV4 NV 90 day: 21.07 mpg (US) ACCELICA - '95 Toyota Celica GT Convertible Last 3: 23.46 mpg (US) The Van - '05 Chevrolet Uplander LS LWB 90 day: 21.04 mpg (US) Thanks: 4 Thanked 31 Times in 12 Posts jakobnev - that's a great idea. This would eliminate the fuel waste of pulling into gas stations more often (though I usually engine-off coast in anyway). I don't think I would actually do it because of storage issues, but it is a really good solution to the mind puzzle of what would be the best way to commute with the least weight in fuel and the least inconvenience. __________________ "You too can get 50 Miles per Gallon, all it will cost is your self-respect."
 01-22-2012, 12:17 PM #6 (permalink) Eco-ventor     Join Date: Oct 2010 Location: sweden Posts: 1,501 Princess - '92 Mazda MX-3 GS House of TudorTeam Mazda 90 day: 53.54 mpg (US) Shirubāarō (*´ω｀*) - '05 Toyota Prius Executive Team Toyota 90 day: 53.13 mpg (US) Thanks: 64 Thanked 607 Times in 384 Posts Well, i suppose if you could be bothered, you could make a sealed transfer system, and eliminate evap and dripping losses too. __________________ 2016: 128.75L for 1875.00km => 6.87L/100km (34.3MPG US) 2017: 209.14L for 4244.00km => 4.93L/100km (47.7MPG US)
 01-22-2012, 09:00 PM #7 (permalink) Master EcoModder   Join Date: Oct 2011 Location: ellington, ct Posts: 829 Thanks: 44 Thanked 103 Times in 80 Posts Isn't this why you buy a scanguage or mpguino? I'm all for trying to monitor mileage, but, when it results in wasting time and fuel, it gets kind of silly. Reminds me of the TDI guys and their ridiculous (IMO) ventectomies. never could figure out why someone trying to get better mileage would want to mod their vehicle to be heavier and risk fuel spillage.
 01-23-2012, 02:15 PM #8 (permalink) Master EcoModder     Join Date: Jul 2010 Location: Belgium Posts: 4,667 GasDwarf - '13 Volkswagen up! EcoFuel CNG Thanks: 176 Thanked 643 Times in 510 Posts You could also drive until the reserve light comes on solidly, then always fill up ASAP with the same volume of fuel. You won't have a tank average, but you can monitor your miles-to-reserve-on-X-gallons and try to better that number. You can make it more accurate of keeping track of how many miles you do before filling up, and adding them to the next miles-to-reserve. That said, the weight savings of half a tank won't matter very much when there's 3 people and their luggage in the car.
 01-25-2012, 03:56 AM #9 (permalink) Mechanical engineer     Join Date: Jan 2009 Location: Kitee (Finland) Posts: 1,077 Siitin - '98 Seat Cordoba Vario 90 day: 58.56 mpg (US) VW Lupo 3L --> 2L - '00 VolksWagen Lupo 3L Diesel 90 day: 104.94 mpg (US) A8 luxury fuel sipper - '97 Audi A8 1.2 TDI 6 speed manual 90 day: 64.64 mpg (US) Audi A4B6 Avant Niistäjä - '02 Audi A4b6 1.9tdi 96kW 3L 90 day: 54.57 mpg (US) Tourekki - '04 VW Touareg 2.5TDI R5 6 speed manual 90 day: 32.98 mpg (US) A2 1.4TDI - '03 Audi A2 1.4 TDI 90 day: 45.68 mpg (US) A2 1.4 LPG - '02 Audi A2 1.4 (75hp) 90 day: 28.67 mpg (US) Thanks: 219 Thanked 585 Times in 270 Posts For venctonomy. Extra 10 liters or 8.4 kg in the tank increases fuel consumption about 0.3% to 0.6%. Difference in diesel price between various stations can be easily over 10% at least in Finland. Calculate which saves more if you can drive over 200 km more and the cheapest station happens to be on your way... So you are able to get to the cheapest station more often than with "smaller" tank. If the cheapest station is next to you it does not help so much, but even then you can do longer trips without the need to fill in at those more expensive pumps. And yes Geo Metropolis I think your theory works just fine. __________________ https://www.linkedin.com/in/vesatiainen/ Vesa Tiainen innovation engineer and automotive enthusiast
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Quote:
 Originally Posted by euromodder You could also drive until the reserve light comes on solidly, then always fill up ASAP with the same volume of fuel. You won't have a tank average, but you can monitor your miles-to-reserve-on-X-gallons and try to better that number. You can make it more accurate of keeping track of how many miles you do before filling up, and adding them to the next miles-to-reserve. That said, the weight savings of half a tank won't matter very much when there's 3 people and their luggage in the car.
Of the 4 cars I've driven regularly enough to have an idea of when the low/reserve gas light comes on, none of them have been anywhere near reliable. one of them (admittedly an old lug of a car) has a 2+ gallon variation in terms of when it comes on. It's also heavily influenced by the angle the car is on. Sort of the same flaws as logging by analog gas gauge, really.

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2001 Prius - 170,000 KM - just got it (no consistent FE numbers yet)