What's in your tank? AAA says gasolines with more detergent save money in the long run

What would've been helpful is for them to list the names of unacceptable brand as well. If the name is not listed on the top tier list, does it make it unacceptable or did they simply not look at it just because it's too small?

I was interested in ethanol free gas and looked up the stations around where I live that sell it. Most are small no big name gas stations. Does that mean these pure gas is unacceptable? Certainly it's considered to be superior to gas from top brands that contains ethanol. How complete is the AAA research? How many different brands did they look at?

 

There's the federal standard which would be unleaded 87 Oct (89 being highest) depending on state regulations will determine what other crap they add to fuel in CA we have the "summer" blend which raises price

 

BP is huge. Conoco Phillips is pretty much right there too. Both companies dominate the north slope activities in AK. (Lots of oil still there. Lots. They are just waiting for a regime change in DC)

 

No brand name gasoline will be exempt from Ethanol, it's an EPA requirement. Smaller vendors can be exempt, don't recall the reg hat allows this but I recall independent gas stations outside Houston advertising Ethanol free gas.

 

The reason there is a difference in Octane rating at different elevations can be a bit confusing, but let me do my best to summarize. The Octane rating is the % of Octane (actually Iso-Octane and Heptane) that knocks at the same compression ratio as the equivalent gasoline. So we have some very expensive 1 cylinder engines in our lab that we run a gasoline blend and we "listen" for the knock. It is recorded digitally but not that long ago people would actually listen to for the ping. We change the compression ratio of the cylinder to achieve the knock. Once the knocking occurs, we have our Octane rating (and we run a high Octane and a low Octane test fuel). We then do some bracketing of the compression ratio for a low and a high (based on test fuels) and then plot the data. When the actual gasoline sample knocks, we figure our it's Octane rating based on the test fuels. The smallest compression ratio where the gasoline begins to knock is used as it's Octane rating. Since at higher altitudes, e.g., Denver, the atmospheric pressure is lower, so less pressure, or compression ratio, is needed to get the knocking so less Octane rating is required.
Clear as mud???

 

Use what the manual tells you... toyota designed and tested the engine, not fuel companies..

 

No I'm not saying that. You should follow the manufacturer's recommended minimum octane. However, what I am saying is if you took an engine and ran it with 85 octane in Denver and then the same engine was run at sea level with 87 octane, you should get the same performance out of it.

 

Is that taking into consideration variations of barometric pressure at different elevations ?...

 

The ECU might be able to adjust timing for that. Just speculation, I don't know enough.

 

Your mas air flow sensor can pick up the difference in elevations do to the thinner air..

 

Barometric pressure is the same as the air pressure in meteorological terms.

 

Not entirely true.. (if we're speaking of the same meaning)...Not the best chart graphically , but stats are correct none the less, elevations are on far left column...

The table below indicates air pressure at elevations below and above sea level.


Altitude Above Sea Level Absolute Barometer Absolute Atmospheric Pressure
feet meters inches Hg mm Hg psia kg/cm2 kPa
-5000 -1524 35.7 908 17.5 1.23 121
-4500
aprox. deepest point of Sognefjorden, Norway -1372 35.1 892 17.2 1.21 119
-4000 -1219 34.5 876 16.9 1.19 117
-3500 -1067 33.9 861 16.6 1.17 115
-3000 -914 33.3 846 16.4 1.15 113
-2500 -762 32.7 831 16.1 1.13 111
-2000 -610 32.1 816 15.8 1.11 109
-1500 -457 31.6 802 15.5 1.09 107
-1000 -305 31.0 788 15.2 1.07 105
-500 -152 30.5 774 15.0 1.05 103
01) 0 29.9 760 14.7 1.03 101
500
aprox. Møllehøj, Denmark 152 29.4 746 14.4 1.01 99.5
1000 305 28.9 733 14.2 0.997 97.7
1500 457 28.3 720 13.9 0.979 96.0
2000 610 27.8 707 13.7 0.961 94.2
2500 762 27.3 694 13.4 0.943 92.5
3000 914 26.8 681 13.2 0.926 90.8
3500 1067 26.3 669 12.9 0.909 89.1
4000 1219 25.8 656 12.7 0.893 87.5
4500
aprox. Ben Nevis, Scotland, UK 1372 25.4 644 12.5 0.876 85.9
5000 1524 24.9 632 12.2 0.860 84.3
6000 1829 24.0 609 11.8 0.828 81.2
7000 2134 23.1 586 11.3 0.797 78.2
8000 2438 22.2 564 10.9 0.768 75.3
9000 2743 21.4 543 10.5 0.739 72.4
10000 3048 20.6 523 10.1 0.711 69.7
15000 4572 16.9 429 8.29 0.583 57.2
20000
aprox. Mount McKinley, Alaska, US 6096 13.8 349 6.75 0.475 46.6
25000 7620 11.1 282 5.45 0.384 37.6
30000
aprox. Mount Everest, Nepal - Tibet 9144 8.89 226 4.36 0.307 30.1
35000 10668 7.04 179 3.46 0.243 23.8
40000 12192 5.52 140 2.71 0.191 18.7
45000 13716 4.28 109 2.10 0.148 14.5
50000 15240 3.27 83 1.61 0.113

 

I grab whatever gas happens to be closest to me when I realize I'm getting low. I'm gonna die some day, and worrying about what techrosuperduparadditive is or is not in my gas, is time I will never get back.

 

Not exactly sure what your post is showing but barometric pressure is defined as the force exerted by an air mass per unit surface area. That equals air pressure. Pressure is force per unit area. Regardless if it's air, your hand or a cannonball hitting a pirate ship. Force over an area is pressure.

 

Oh I get that, I thought you were saying that pressure is the same regardless of elevation, I must've misunderstood...

 

For the sake of sounding ignorant, what is SC? Besides South Carolina, Sports Center, etc? Thanks!

 

SC is supercharger..

 

Bringing this back up.. Colorado guys, what do you fill up with? I understand the difference that altitude makes. But the manual also says use 87 which largely you can’t find at pumps here.. is 85 what everyone is using? Just trying to treat the new truck the best I can. Let me know!

 

I find 87 pretty much everywhere in CO. I prefer Maverick pure dino, no ethanol 87 otherwise Shell 87 with up to 10% ethanol. I only see crappy 10% ethanol added 85 at Sam's Club or Costco for the most part.

 

maybe that’s my problem. I typically only fill up at sams or Costco haha. So 87 and if not available 91?

 

Yep. Get a Maverick rewards card. You can save 6 cents a gallon and use pure gas if you want. I try to avoid 10% ethanol gas but sometimes there is no choice. I go to Sam's Club a lot but never buy gas there because of no 87.

 

Actually most gas stations have 85 here too. I've never bought 85. Not sure why Sam's and Costco only have 85 and 91

 

Yeah at least it isn’t e85

 

Late to this party, but THIS right here ^^^^, is the real winner, and truly info from the inside.

 

It's a lot cheaper for a gas station to only utilize two underground tanks to store regular and premium gas and then simply "splash"mix the two grades into "mid". Pointless to mix regular and premium gas and then store in a third tank. Technically you could manually "splash' mix your own midgrade by pumping 50% of 85 and then 50% of 89 to make 87 for example. I've seen people do this. Cheaper than actually selecting midgrade sometimes or when there is no midgrade available like Sam's Club or Costco..

 

Wait!...What? I don't think that would be legal in Texas, "splash mixing" at the pump.