Is it just my imagination?
#1
08-20-2004, 05:36 AM
Does the BP gas that I use at a particular station give me significantly better mpgs? That's my hypothesis.
Background: About 2 months ago, something happened when I filled up at my favorite BP gas station near my house. Where I normally get 64-65 mpgs on the dash readout in the summer, suddenly I was seeing 70. Sure enough, after finishing the tank, I went 859 miles for 64.8 calculated mpgs. The next tank was very similar -- 865 miles for 64.3 calculated mpgs. Those two tanks are the highest I've recorded in the 2 years I've owned the car, and by 4 mpgs at least.
The weather has been the same, I'm driving the same route back and forth to work, nothing has changed.
So, I decided on my last tank to fill up at Marathon. Yesterday I finished the tank -- 764 miles at 58.5 calculated mpgs, which is what I *used* to get in the summer before these last 2 BP tanks.
I filled up at my favorite BP again last night. Then a really peculiar thing happened on the flat road out of BP back to my house. I was driving steadily along, about .3 miles from BP, at 60 mpgs on the FCD, when all of the sudden I felt a surge. I had to back off on the gas to maintain speed (the surge was accelerating the car), and once I got it steady, was at 100 mpgs on the FCD.
So this morning, I drove my regular 13.2 mile route to work, and when I got here....84.7 mpg on the dash, back up to what I'd expect from the previous 2 BP tanks.
Was I imagining things? I wasn't expecting this "surge", so my gut feeling was I burned all the old gas out of the fuel line, and the BP gas mixture hit when I felt the surge. Now, this surge wasn't like Nitrous or anything...but you could feel it. What do you think?
It takes a while to test this theory, as I have to go through a whole tank of gas to do it, but my preliminary findings say, there's something in that BP gas.
Mark
Background: About 2 months ago, something happened when I filled up at my favorite BP gas station near my house. Where I normally get 64-65 mpgs on the dash readout in the summer, suddenly I was seeing 70. Sure enough, after finishing the tank, I went 859 miles for 64.8 calculated mpgs. The next tank was very similar -- 865 miles for 64.3 calculated mpgs. Those two tanks are the highest I've recorded in the 2 years I've owned the car, and by 4 mpgs at least.
The weather has been the same, I'm driving the same route back and forth to work, nothing has changed.
So, I decided on my last tank to fill up at Marathon. Yesterday I finished the tank -- 764 miles at 58.5 calculated mpgs, which is what I *used* to get in the summer before these last 2 BP tanks.
I filled up at my favorite BP again last night. Then a really peculiar thing happened on the flat road out of BP back to my house. I was driving steadily along, about .3 miles from BP, at 60 mpgs on the FCD, when all of the sudden I felt a surge. I had to back off on the gas to maintain speed (the surge was accelerating the car), and once I got it steady, was at 100 mpgs on the FCD.
So this morning, I drove my regular 13.2 mile route to work, and when I got here....84.7 mpg on the dash, back up to what I'd expect from the previous 2 BP tanks.
Was I imagining things? I wasn't expecting this "surge", so my gut feeling was I burned all the old gas out of the fuel line, and the BP gas mixture hit when I felt the surge. Now, this surge wasn't like Nitrous or anything...but you could feel it. What do you think?
It takes a while to test this theory, as I have to go through a whole tank of gas to do it, but my preliminary findings say, there's something in that BP gas.
Mark
#2
08-20-2004, 07:14 AM
Maybe they just have more accurate pumps.
Others have posted here that the government only requires pumps to have an accuracy of 10%.
I speculate that businsses know this and keep pumps tweeked so we get 9 gallons when we think we are getting 10. This is legal.
Maybe BP is too ethical, or stupid, to follow suit.
Others have posted here that the government only requires pumps to have an accuracy of 10%.
I speculate that businsses know this and keep pumps tweeked so we get 9 gallons when we think we are getting 10. This is legal.
Maybe BP is too ethical, or stupid, to follow suit.
#3
08-20-2004, 09:43 AM
Hi Buzz70:
___Whenever I fill from an absolutely dry tank (< .2 gallons left) or especially when I fill the vapor recovery HW, the first few miles are driven at incredible mileage per the FCD. I once had the FCD pegged at 150.0 mpg for maybe 2/3 the way home from the local BP station and it’s 5 miles of city type driving away. As the charcoal canister drains liquid fuel, it bypasses what the FCD measures and you are essentially receiving free mpg according to the FCD until everything balances out again. I feel this surge and see the wild mpg for a few miles after one of these super fills but it goes away after a few miles and the FCD begins to act normally again. At least that is the way it works in my Insight. Most don’t fill there tanks up to the filler neck, have never filled the vapor recovery HW, or drive their automobiles until the last ¼ gallon or less is left in them. Some Hypermilers (I qualify) tend to do all of the above and with that, I have seen and felt the exact same thing you described and it is not a Lean-burn to NOx purge event causing it but the vapor recovery HW doing its job. Again, it does not happen every time but usually after a Vapor Recovery fill or from an almost bone dry tank to filler neck when the vapors are most pronounced and must condense in the canister for a burn without measure as I tend to see it.
___Kenny, 10% off? No way are the pumps that far off. I will do some searching on this topic over the next few days but I would be surprised if the pumps are 2% off at most.
___Good Luck
___Wayne R. Gerdes
___Hunt Club Farms Landscaping Ltd.
___Waynegerdes@earthlink.net
___Whenever I fill from an absolutely dry tank (< .2 gallons left) or especially when I fill the vapor recovery HW, the first few miles are driven at incredible mileage per the FCD. I once had the FCD pegged at 150.0 mpg for maybe 2/3 the way home from the local BP station and it’s 5 miles of city type driving away. As the charcoal canister drains liquid fuel, it bypasses what the FCD measures and you are essentially receiving free mpg according to the FCD until everything balances out again. I feel this surge and see the wild mpg for a few miles after one of these super fills but it goes away after a few miles and the FCD begins to act normally again. At least that is the way it works in my Insight. Most don’t fill there tanks up to the filler neck, have never filled the vapor recovery HW, or drive their automobiles until the last ¼ gallon or less is left in them. Some Hypermilers (I qualify) tend to do all of the above and with that, I have seen and felt the exact same thing you described and it is not a Lean-burn to NOx purge event causing it but the vapor recovery HW doing its job. Again, it does not happen every time but usually after a Vapor Recovery fill or from an almost bone dry tank to filler neck when the vapors are most pronounced and must condense in the canister for a burn without measure as I tend to see it.
___Kenny, 10% off? No way are the pumps that far off. I will do some searching on this topic over the next few days but I would be surprised if the pumps are 2% off at most.
___Good Luck
___Wayne R. Gerdes
___Hunt Club Farms Landscaping Ltd.
___Waynegerdes@earthlink.net
#4
08-20-2004, 10:29 AM
Hi Kenny:
___The following was about the best I could find after some minutes inside of the Google search engine.
Inaccuracies at the Pump
___1/10 of a gallon over 11 total gallons (< 1%) appears to be the spec but this isn’t exactly said in the second to last post?
___Good Luck
___Wayne R. Gerdes
___Hunt Club Farms Landscaping Ltd.
___Waynegerdes@earthlink.net
___The following was about the best I could find after some minutes inside of the Google search engine.
Inaccuracies at the Pump
___1/10 of a gallon over 11 total gallons (< 1%) appears to be the spec but this isn’t exactly said in the second to last post?
___Good Luck
___Wayne R. Gerdes
___Hunt Club Farms Landscaping Ltd.
___Waynegerdes@earthlink.net
