Differnet gas nets 10mpg gain

Discussion in 'Gen 2 Prius Fuel Economy' started by problemchild, Sep 13, 2008.

  1. problemchild

    problemchild New Member

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    Well I have tried every gas brand in Socal. The worst was mobile at 39mpg, the middle was chevron at 44-45mpg and the best was shell at 45-47mpg.

    On a whim the last time I pumped at shell I used the premium. Normally the mfd starts off at 40mpg or so and climbs a tiny bit to settle on that tanks mpg.

    This time with the Shell Premium I started off at 59mpg. I have never got any where near that on any tank under any condition. I preceded on to my next customer and drove as I normally do with about 50% highway and 50% street. When I got to my customer 14 miles away I looked at the mfd. Much to my surprise it was a whopping 58.7mpg. I continued to drive the rest of the day and it never went below 55.6mpg which is where it is now with 87 miles on this tank.

    Hard to believe premium could make such a difference. Same driving, same conditions, same route.
     
  2. MR.K

    MR.K New Member

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    Does Shell's best have 10% ethenol in it ? ..That's the biggest mileage killer ...maybe they use it in the cheaper grades ??
     
  3. mrblaise

    mrblaise Go Lakers!!

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    I've used Union 76 the last few weeks and have noticed a marked increase in my MPG. It's no fluke either. I had to get a tank of mobil in between this week and my MPG dropped 4 MPG. I refilled with Union 76 and it shot back up again. Based on the OP's post, I'm tempted to try the premium grade too.
     
  4. CBarr31

    CBarr31 Active Member

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    I have found through a lot of driving, 126K+ on 2006 Prius, that using premium tank after tank doesn't really help your MPG's but using it every 3rd or 4th tank does show a marked increase. In this kind of app it is almost acting as a "cleaner".

    I too have found that Shell gas especially the premium with the added "gunk" cleaner additives is the best of the premium brands.

    As has been noted THOUSANDS of times before on other threads ethanol sucks and the 10% mix causes a 4-5 MPG regardless of the octane rating. My $0.02
     
  5. Syclone

    Syclone Member

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    The 64MPG question here is: Does anyone know what gas companies don't use Ethanol in the Summer?
     
  6. tasker109

    tasker109 New Member

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    it doesnt make any sense to use premium. its 30 cents a gallon more and even if you DO get more mpg's, you dont save anything because it costs more....
     
  7. hobba

    hobba New Member

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    BP in Florida does not use ethanol in their gas.
     
  8. problemchild

    problemchild New Member

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    Huh?

    You took math in --->PUBLIC<---- school didn't you?

    .30 cents x 9 gallons is 2.70 which is approx. 2/3rds the price of 1 gallon. Two thirds of a gallon would take me 28 miles. Premium fuel will net me ten miles per gallon x 9 gallons which will take me 90 miles.

    90 miles
    28 miles
    = an extra 62 miles on premium.

    DOH!!!!!!!!!!!!!!!!
     
  9. richard schumacher

    richard schumacher shortbus driver

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    I'd bet a dime that this experiment used one tank of gas each? It wasn't the brand or octane of gas, it was the details of the weather, the traffic, the route, and your driving styles on each of those tanks. And in any given region, if one gas uses ethanol to reduce air pollution, then they all do. Use 87 octane as recommended by Toyota in the owner's manual and don't worry about it.
     
  10. tasker109

    tasker109 New Member

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    hold on now pedro....i see your calculations however, i have been partaking of the knowledge and experience of many trusted posters and cant believe that out of the clear blue sky, somebody comes up with a statement and you take it for gospel. if it was possible to get more than 10 mpg's, i know someone would have told us about it before. i am willing to concede that maybe, just MAYBE, changing to premium might gain an extra 5 mpg's or so. i dont know. i never tried. i never read it on these forums...i am just saying maybe its possible. but i cant believe that you would gain 10 mpg G-U-A-R-A-N-T-E-E-D by switching to premium. my calculations were done on the extra MAYBE 5 mpg's. given its 30 cents a gallon more for premium, if i bought 10 gallons and spent $3.00 more and for that 10 gallons I got 50 more miles, and give that i get 48 mpg now with hopes of gettintg 53, it would almost be a wash. can you agree with MY explanation of calculation?? :confused:
     
  11. nooaah

    nooaah New Member

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    Wow, talk about elitist. :rolleyes:
     
  12. Jiipa

    Jiipa MGySgt USMC (Ret)

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    And where did you learn to spell, "Differnet"????
     
  13. markderail

    markderail I do 45 mins @ 3200 PSI

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    Here in Canada:
    - Shell is the best
    - Ultramar is / seems the same as Shell
    - Petro Canada - AWFUL - lose 20% mileage
     
  14. Sheepdog

    Sheepdog C'Mere Sheepie!

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    Problemchild is just that. A Problem child and a troll. I have found that the best way to take him is to ignore him as I do. Then you are a happy camper.
     
  15. JamesWyatt

    JamesWyatt Señior Member

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    All other things being equal, premium fuel reduces mileage. Higher octane = less energy, right? Is it possible that your gas station's premium contains less (or no) Ethanol than the regular?

    I put in premium once by accident, and the car couldn't get out of it's own way. It was like I'd put diesel in it or something. Mileage dropped by at least 5 mpg. It was torture to drive that tank, and I swore I'd never touch premium again.
     
  16. kazots

    kazots LifesaBeach

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    'Problemchild" you were a little rough with "Tasker109" I think you bring a interesting point with the premium gas and I will test it out. I have read other threads that say the opposite but is worth a try. Thanks
     
  17. jdonalds

    jdonalds Active Member

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    Three comments:

    1) I expected to get 10% less mpg when in Oregon where ethanol is apparently required by law. I didn't notice any significant drop in mpg even though I had to fill twice in that state. We were on a 3,500 mile trip from SoCal to Canada and back and my driving habits were pretty constant on the whole trip. I recorded my mileage and just didn't see any effect. I believe others have. I wonder why I didn't?

    2) I tried one tank of high octane and didn't experience an apparent increase in mileage. For me I'll stick with 87.

    3) I don't go looking for Shell stations but I've noticed a significant increase in mpg, easily 5mpg+, when filling with Shell. Interesting because I've avoided Shell most of my life after working on engines in the 50's and 60's. Any engine that regularly used Shell was loaded with carbon and residue. I suppose the formula today is quite different.
     
  18. johnford

    johnford Old Junior Member

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    I always fill up at Murphey Gas in Arkansas which has ethanol added but during the recent rash of (wo in a row) hurricanes in Arkansas, they brought in fuel from another source. I was told it had no ethanol. I got 7mpg higher during my use of this gas. I drive 87 miles each day on a rural paper route, so didn't get to enjoy the non alky gas for long.... jf
     
  19. markderail

    markderail I do 45 mins @ 3200 PSI

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    Same in Canada - Shell gets me below 5.0 l / 100km, and Petro Canada 5.2 or worse.

    I noticed it more in total km driven, with Petro Canada, I never get close 600km. With Shell, 620 to 630 when the last PIP turns off.

    Same driving, same conditions.
     
  20. dwreed3rd

    dwreed3rd New Member

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    How premium fuel affects your mileage depends mostly on your engine. If your car was designed to run on regular, you will probably not see any improvement with premium. And as some posts indicate, may actually get less MPG. espesially if it is an older car that does not have the ability to adjust your timimg and fuel mixture automatically.

    If, however, your car was designed to use and recommends using premium, or can automatically adjust timing and fuel mixture, you may get an improvement in MPG.

    You are correct, the octane does not add energy, but it allows an engine that is designed to take advantage of a high compression ratio, to get get more of the energy out of each ignition. Thus, the result is more HPR, or less throttle for to obtain the same HPR.

    The difference may also vary due to driving habits. Agressive driving such as rabbit starts and high speed driving may actually find an improvement in MPG using premium over regular, if the car is designed to take advantage of it. However, a driver that accelerates slowly and rarely does any high speed driving, may notice little, if any, improvement in using premium over regular, even if it is recommended for the vehicle.

    Not sure how you get your fuel where you are. Here on the east coast, for the vast majority of brands, it all comes through the same pipeline from the gulf. A difference does not exist until the additives are added at the storage depots. And as it was pointed out, these are detergents, etc., and do not contain energy, so should not affect MPG.

    Ethanol is usually the last ingredient to be added, because of it's tendancy to absorb water. I personnally believe this may well be a likely cause of variations in MPG between brands or even between tank fulls at the same station. I am not comfortable with this part of the process or it's controls or regulations. There have been a number of articles siting variations in the ethanol % from independent testing, even above 15% in some cases. Sorry, don't remember the source.

    Net is, that if the car is designed to use premium, while it mat or may not significantly affect gas mileage, it is better for the car in the long run. If regular is recommended, little if any benefit, or even degradation may result in using premium.

    And, of course, the only way to know absolutely is to track your own results.
     
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