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04-25-2011, 01:53 PM | #1 |
Pizza D
Drives: 2007 yaris 3D MT Join Date: Apr 2011
Location: US
Posts: 10
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"Letting your gas tank get below 1/3 full will cost you MPG"-Myth?
I've read that letting the gas tank get below 1/3 full can cause you to lose MPG when you go around turns. Supposedly your gas will not go to the engine if it is being slung to the side? I do not know much about cars, am relatively new to hypermiling, and deliver pizzas (lots of hard 90 degree turns at highest possible speed). Thoughts?
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04-25-2011, 01:55 PM | #2 |
Drives: 09 Yaris 3dr HB, BRZ Join Date: Mar 2011
Location: GTA
Posts: 222
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electric fuel pumps..
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04-25-2011, 02:07 PM | #3 |
Pizza D
Drives: 2007 yaris 3D MT Join Date: Apr 2011
Location: US
Posts: 10
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are you saying this is a myth? like i stated, i don't now much about cars, and certainly not what an electric fuel pump does
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04-25-2011, 04:01 PM | #4 |
Drives: '08 LB MT Bayou Join Date: Oct 2008
Location: Colorado
Posts: 1,671
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Never heard that one before. But the premise is all wrong. If gas is getting slung up to the side and is not making it to the pump, then you're actually using no gas, which is good for MPG. Worst that could happen is that you get an air bubble in the fuel lines which might make the car hiccup.
Of course if you are driving in circles at high speed and the fuel is permanently slung to the side of the tank, that's a different story altogether. |
04-25-2011, 04:36 PM | #5 |
"LibertyRides!"
Drives: 2010 Yaris 3Dr LB | 2020 Stang Join Date: Mar 2010
Location: State College, PA, USA
Posts: 576
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Hmmm? Never heard that? I always thought letting your tank go well under 1/8 all the time 'could' cause your fuel pump to go early? The fuel pump is inside the gas tank...
Cheers!
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~ Mark ~ 2010 Yaris 3-Dr Liftback, 5-Speed Manual, P185/60R 15, Bayou Blue Pearl I Love my YARIS - (Click below to see Gaslog): Most miles Tank: 538 tank/10.148 gal = 53.015 MPG / Most MPG: 54.95 MPG (ethanol) 425 tank/7.73 gal "The evils of government are directly proportional to the tolerance of the people." -- Frank Kent |
04-25-2011, 06:25 PM | #6 |
Drives: 09 Yaris 3dr HB, BRZ Join Date: Mar 2011
Location: GTA
Posts: 222
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Yes now that one i have heard, let the tank run real low and the pump is no longer submerged therefor getting hot... but i dunno if the yaris has an in tank pump or not..
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04-25-2011, 06:38 PM | #7 |
Drives: 2010 Yaris Sedan Join Date: Feb 2010
Location: Kansas
Posts: 871
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And also, with the temp changes this time of year, you are much more prone to getting condensation in the tank. The more air (with moisture trapped in it) in the tank is subject to cold-hot changes make it more prone to picking up moisture in the tank.
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04-25-2011, 09:33 PM | #8 |
daily driver
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ive only heard that letting your tank run lower than 1/4 tank consistently over the life of the car will cause premature fuel pump wear.....im going to play it on the safe side, personally.
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06-02-2011, 12:12 PM | #9 |
Dobbiedoo
Drives: 2009 5 door Hb Yaris Join Date: Aug 2010
Location: Stoughton,Ma
Posts: 36
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The tank has baffles built in, so there is never a chance of gas not being around the pump. As mentioned before the pump can overheat with a really low level of gas, shortening it life.
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06-02-2011, 12:28 PM | #10 |
Obsessed with 1.5L
Drives: '10 PW Yaris Sedan Join Date: Feb 2011
Location: Westminster, MD
Posts: 907
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our cars have pulse fired fuel pumps...i'm not worried about it
hell, most of my "fun corners" are when i'm doing some EOC (engine off coasting)
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-Greg...the Exhaust Freak. -10 PW sedan 107whp/110wtq, full exhaust, suspension bits, TRD LSD -06 Highlander 3mzfe Limited AWD -82 Malibu, 1uzfe swap -97 Tercel coupe, 1nzfe/4.31 -96 Tercel coupe, Turbo 5efe, autoX -96 Tercel 4dr |
06-03-2011, 08:21 AM | #11 |
Crazy Oil Sniffer
Drives: MM 09 Yaris 5 Dr LB "Click" Join Date: May 2009
Location: ME
Posts: 498
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Malibuguy,
Can you describe a pulse fired FP for me? I haven't heard the the term before and I'm unfamiliar. What are the advantages? Thanks in advance, R2 |
06-03-2011, 01:08 PM | #12 |
Obsessed with 1.5L
Drives: '10 PW Yaris Sedan Join Date: Feb 2011
Location: Westminster, MD
Posts: 907
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for at least toyotas small cars (in terms of the years i'm referring to)
'97 & later Tercel, Echo, Yaris feature returnless fuel systems to reduce the heat thats introduced into the fuel being pumped up to the rail (soaking up heat there from the engine bay) then back to the tank. Going to returnless reduces evaporative emissions which is also aids in mileage. The fuel pumps are pulse fired to maintain rail pressure, since they can't be run all the time. does that make sense? let me know...i'm kinda of crappy at explaining things
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-Greg...the Exhaust Freak. -10 PW sedan 107whp/110wtq, full exhaust, suspension bits, TRD LSD -06 Highlander 3mzfe Limited AWD -82 Malibu, 1uzfe swap -97 Tercel coupe, 1nzfe/4.31 -96 Tercel coupe, Turbo 5efe, autoX -96 Tercel 4dr |
06-03-2011, 08:03 PM | #13 |
Crazy Oil Sniffer
Drives: MM 09 Yaris 5 Dr LB "Click" Join Date: May 2009
Location: ME
Posts: 498
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Nope, makes perfect sense, thank you! I never thought about the returnless aspect of the fuel system needing a different type pump. I see what you're saying.
These seem to be reliable units-at least I haven't heard of any problems? My last vehicle my Dad aand I got really good at dropping the tank, if you know what I mean! Thank you, R2 |
06-04-2011, 08:14 AM | #14 |
Obsessed with 1.5L
Drives: '10 PW Yaris Sedan Join Date: Feb 2011
Location: Westminster, MD
Posts: 907
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my tercel chassis has about 210-215k on it, still original fuel pump...but i did have to replace the tank cuz it rotted out from being a NE car
all cars by now are returnless
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-Greg...the Exhaust Freak. -10 PW sedan 107whp/110wtq, full exhaust, suspension bits, TRD LSD -06 Highlander 3mzfe Limited AWD -82 Malibu, 1uzfe swap -97 Tercel coupe, 1nzfe/4.31 -96 Tercel coupe, Turbo 5efe, autoX -96 Tercel 4dr |
06-04-2011, 08:22 AM | #15 | |
USAF_SrA_E-4
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This was on Mythbusters and it was busted.
If you don't know what I am talking about (proven wrong)
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Quote:
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06-04-2011, 10:24 AM | #16 |
Nothing beats a Toyota!
Drives: 2013 Yaris 5 dr liftback Join Date: Jan 2009
Location: Indianapolis, Indiana
Posts: 564
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Wouldn't the tank with less volume actually be lighter and get better mileage from less weight?
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Big Dave Indianapolis, IN Synthetic Oil....its in my car.....for at least 10,000 miles! |
06-05-2011, 11:33 AM | #17 |
Drives: 2010 5 door hatch w/5 sp man. Join Date: Jan 2011
Location: Coventry, CT
Posts: 160
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Yes
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06-05-2011, 02:13 PM | #18 |
Drives: 2008 5 sp. LB Join Date: Oct 2010
Location: Idahoi
Posts: 268
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I wait as long as possible to fillup. Partly because hauling less dead weight around is always a good thing, and partly because when I calculate my mileage after the fillup I want the biggest numbers possible for the most accurate determination of how I did that tank.
Just because the fuel pump is normally submerged, does not mean running low levels of fuel are harmfull, I gotta think they take guys like me into account when they design the things! I don't worry about my fuel pump in other words. |
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