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Drop in Fuel Mileage? I may have a solution.

Discussion in 'Gen 3 Prius Fuel Economy' started by ALS, Aug 20, 2017.

  1. ALS

    ALS Active Member

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    Earlier this year a friend enlightened me to better gas means better fuel mileage. I'd been running what ever was cheapest for years in my cars, and watched my gas mileage drop a little bit year after year.

    My Volvo use to get 29.25-29.50 miles per gallon before E10 was mandated in my area. I watched over the last eight or nine years my fuel mileage drop to mid 26's. I was blaming the mandated E10 for my drop in both the Volvo and the 5 mpg drop in the Prius.

    Last year I started with the Volvo waiting until the tank was almost empty and tossed in a bottle of Techron and switched to Shell V-Power + Nitro gasoline exclusively. Any top tier gasoline should work if you don't have Shell in your neighborhood. The Techron was added to accelerate the cleaning during the first tank. I use the Shell because I have one of their stations near my home and the cost is the same as the other stations in the area.

    After about 200 miles I noticed the engine has smoothed out dramatically but the fuel mileage hadn't moved off the mid 26's. I drove it around locally for a few weeks and had filled it up once. I decided on a Sunday last Sept to take a ride to see an automobile museum for something to do. I'm now filling the car up for the third time with Shell V-Power before the start of my trip.

    I'm on my way to the Museum is when I noticed the numbers on my Scan Gauge where climbing past 27 mpg and continued up to just over 29 mpg. On the way back I saw the same fuel mileage numbers stay in low 29's. Took the car to Fl. in December, 1170 miles each way and the fuel mileage never dropped.

    A few months ago I decided to do the cleaning process to the Prius with a bottle of Techron and switched over to Shell 87 exclusively. Being I rarely drive the car on the highway for any length of time, I never really saw the real gas mileage the car was capable of.

    Today I was out this afternoon on a highway run for about three hours. Stock Prius, 70,250 miles, Defender tires 44F-42R, no grill blocks, no Hypermileing, cruise control set at 55 mph with the A/C running the whole time, air temperatures low eighties with Shell 87 in the tank.

    My fuel mileage for the day, round trip at 55 mph with the A/C on the whole time came in at 61.3 mpg recorded by my calibrated Scan Gauge. I've seen during short runs at 65 mph mileage numbers in the 55-56 mpg range in past weeks. This is western Pennsylvania and we have hills around here.

    You are not going to see a major change in the first tank or two. But after a few tanks you should see a jump in your fuel mileage as you eventually clean the gunk that has built up over the years. It took years to build up you're not cleaning the crud out of your fuel delivery system in a tank or two, give it a little time.
     
    #1 ALS, Aug 20, 2017
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  2. MelonPrius

    MelonPrius Senior Member

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    I just put in a 16 oz bottle of Techron a few days ago. My current tank has increased to 58 mpg on the tripometer (which will be close to 55-56 when hand calculated). This is over 330 miles, so I'll see if it holds up. I don't know if the FE improvement is more a result of the Techron, or my increased emphasis on coasting in N when possible.

    I posted this before, but Techron is available at most Costco stores at ~$19 for 6 bottles (16 oz). That's a good deal.
     
    #2 MelonPrius, Aug 21, 2017
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  3. Rmay635703

    Rmay635703 Senior Member

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    Acetone is $2 and cleans the fuel system too
     
    #3 Rmay635703, Aug 21, 2017
  4. Robertto09

    Robertto09 Junior Member

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    #4 Robertto09, Aug 23, 2017
  5. harrysprius

    harrysprius Active Member

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    I'm not sure if this will work as well or not, but I notice a few more miles per gallon with Lucas fuel additive. Next week I'm going to start a trial and see how it does. I'll probably run it for at least a month, and I go through at least two tanks a week. Maybe I can run the Techron the next month and see how it does.
     
    #5 harrysprius, Aug 24, 2017
    Last edited: Aug 24, 2017
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  6. SFO

    SFO Senior Member

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    Is what you are buying the same as "Chevron Techron Concentrate Plus" ??
     
    #6 SFO, Aug 24, 2017
  7. DanMan32

    DanMan32 Senior Member

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    The problem with v-power plus is that it is only available as high octane. High octane for a Prius is a waste of money at best. You only need premium in a vehicle if the owners manual says you must or it is recommended.
    The top tier classification applies for any octane.

    Posted via the PriusChat mobile app.
     
    #7 DanMan32, Aug 26, 2017
  8. ALS

    ALS Active Member

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    I only use 87 in the Prius. The Volvo has a 91 octane or better requirement thus the V-Power+Nitro.

    I will tell you, I tried to lower the octane in the Volvo and filled it with 89 on a trip to save money. It was a fuel mileage disaster, like a 3 mpg drop. At the time it was getting mid 26's and when I filled with the 89 it dropped to 23 mpg. My point is use Top Tier with a higher detergent additive package and over the long term you'll save money with better fuel mileage.
     
    #8 ALS, Aug 26, 2017
  9. MelonPrius

    MelonPrius Senior Member

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    I don't think so, it's the fuel injector cleaner, but I'm not sure if there's a big difference: Chevron Techron Fuel Injection Cleaner, 16 oz, 6 ct

    If your injectors are already clean, then it's likely snake oil, or a nice placebo. Personally, I think that injectors will stay clean if you use top tier gasoline, especially if the car has relatively low miles. But, since it might be snake oil, I try to get it on sale. This stuff goes on sale periodically and you can get a case for $12, if you have a membership and can wait.

    I just got 55.6 mpg on my last tank after putting a 16 oz bottle in, which is near my all time high. But I got 54.1 mpg on the previous tank (before putting in the Techron), and the temps have started to go down, creating less pressure on my AC. And my average mph decreased in my last tank, which helped. I guess I'm saying that I don't give much credit to my slight bump in mpg to the Techron, even if there's a slight placebo effect. I use it mostly to give me a peace of mind about keeping my clean injectors clean, if I can get it cheap.
     
    #9 MelonPrius, Aug 26, 2017
  10. jdonalds

    jdonalds Active Member

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    I think Techron and Sea Foam are the same type of products. I've had really good results with Sea Foam.

    Our 2008 Prius normally ran in the 45-48 mpg range. But for three tanks of gas it dropped into the mid 30's. I thought it might be the traction battery but after much data gathering that wasn't the problem. It was the ICE. So I dumped 1/2 can of Sea Foam in the gas tank. The problem went away. I figure it must have been dirty fuel injectors.
     
    #10 jdonalds, Aug 30, 2017
  11. harrysprius

    harrysprius Active Member

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    I believe any quality product will work. Lucas works for me, seafoam for you, techron for others. I think the main thing is just to keep the system clean.

    Lucas is my preference for cost savings. I can buy it in the gallon for about $25 and treat 25 tanks of fuel. I haven't taken tank size into consideration, so that may be more on the Prius.
     
    #11 harrysprius, Aug 30, 2017
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