Premium gas have more additive than regular gas!

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This is my long team observation that I discover unconscious.
Gas station that I use are Shell and Philips.

I have a 95 Toyota Camry that I bought a little bit more than 2 year ago. When I bought it, it had 93000 miles.
I only use 93 because I have good result on Subaru Legacy and Mazda Miata, so I do the same to this Camry. Recently the gas is so ridiculous high, so I decide to degrade to 87. I find little to no difference how the car run. I think this car is just a waste to run 93, but I find that my fuel gauge know the difference...

When I used to pump 93 to a full tank, the needle is always over the full line (every tank, no exception). After I switched to 87, the needle no longer move that far, usually sit on the full line. If I use a bottle of Regene, that tank of gas will make the needle over the full line, and continuous for couple tanks more.
From this observation, I think the only explanation is premium gas should have more additive. At least apply to Shell and Philips because I only go to 2 shell gas station and 1 Philips gas station whoever is cheaper. I think I read somewhere about Shell Premium have 5X additive than EPA standard, regular have 2X additive than EPA standard. I feel this sentence is so true...

A side note, I put Lucas UCL today and the needle did move over the full line, so I think there might be some cleaning additive. If I find something worth to post about the UCL, I will post it later.
 
93 octane is a waste of money unless owners manual calls for it...my 07 focus owners manual says to only run 87 octane period, with no aftermarket additives...i try to run mobil as much as possible...shell is good too...93 is a more controlled burn for hi performance motors
 
Are you filling up with the two fuels in exactly the same spot? If not then the way the car sits when you fill up is probably causing the difference. Additive concentrations are extremely low to begin with and the gauge itself relies on just a simple float. Hard to imagine it would float differently no matter what you filled the tank with.

If your manual calls for regular then you should see no difference running higher octane unless you have carbon build-up that is raising the compression ratio. In that case you need to use a combustion chamber cleaner to correct the problem. That would go for all your cars, not just the Camry.
 
Maybe the premium makes the float rise higher?
LOL.gif
 
Shell's web site clearly states the more additives for the premium here... It has the friction modifiers and detergents. I consider the octane number a side effect.
 
I wonder actually how much additive is added in a load of fuel?

Seems all the gasoline in this area comes from two tank farms one in the Florida Panhandle and other other east of us in Georgia.
 
Originally Posted By: Kitto
This is my long team observation that I discover unconscious.
I think this car is just a waste to run 93, but I find that my fuel gauge know the difference...

When I used to pump 93 to a full tank, the needle is always over the full line (every tank, no exception). After I switched to 87, the needle no longer move that far, usually sit on the full line. From this observation, I think the only explanation is premium gas should have more additive. A side note, I put Lucas UCL today and the needle did move over the full line, so I think there might be some cleaning additive.


I agree with your first statement, that you were unconscious when you "discovered" this amazing relationship.

It doesn't matter if you filled up with Spring Water or Premium Gasoline or Olive oil. If you fill it all the way to the top, the fuel gauge will read exactly the same....
 
I'm sure the float reaches the same height regardless of fuel but I guess it's possible something in the fuel could be interfering or adding resistance to the fuel level sensor (potentiometer)
Shell had lots of problems fouling fuel level sensors a few years ago
 
Originally Posted By: Rabbler
I'm sure the float reaches the same height regardless of fuel but I guess it's possible something in the fuel could be interfering or adding resistance to the fuel level sensor (potentiometer)


The potentiometer is encapsulated. Hard to belive something in the fuel is effecting the resistance one way or the other.

Sounds more like a goofy dash gauge, or trapped air inside the fuel vapor recovery system if, indeed, its a legit problem.
 
Encapsulated as in a sealed unit?
Not in my experience. Over 90% of the cars I've worked on the sending unit potentiometer was out in the open exposed to whatever was in the fuel tank. Most had obvious deposits or discolouration on them but still worked fine.
 
Much more plausible reason is that the fluid in the tank simply isn't being filled exactly the same each time.

Let's don't make this harder than it is.
 
When I interviewed the lab guys from the major oil companies several years ago about the level of detergent additives in their different grades of gasoline, since the advertising sometimes suggested a difference, each and every lab guy told me there was no significant difference between their various grades. This is from the horse's mouth. I can't speak about Shell's latest promotion on this subject.
 
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Originally Posted By: dwendt44
Maybe the premium makes the float rise higher?
LOL.gif



boing!!!
 
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