When I go and buy a small amount of fuel(high Octane)......using a gallon or 2 size can.
Are we really getting the high octane from the pump?

With the new style pumps now that share the same hose ,you need to select the proper grade before filling? Correct?

If the guy before you bought 87 octane ......Then you come up to the pump after him push your 91 octane and fill your small 1-2 gallon fuel can .................................................. .........Are you getting 91 octane? Your paying for it, But I think it would need to pump at least a gallon or two before it comes from 87 grade to the 91 grade.

Any of you out there install or work on pumps?
I know it a crazy topic but I always thought about this when making a small purchase at the pumps?.........LOL......LOL............Caper...... ......Lets debate...LOL.......

 

Im thinkin it switches over inside the pump... You are getting what is left from what you see of the hose for sure.. probably half a gallon but still.. you are runnin 90 octane when your done =)

 

Never thought of that, come to think of it I've never had any need for super either.

 

I've poured some mud on a few new gas stations and I could clearly see the plumbing coming up out of the ground. It looks as though all the lines come up to a valve/selector which the pump would attach I guess. Pending on which grade you pick would determine the position of the valve. (just a guess) I too wonder if you would have some gas of a different grade in the line prior to pumping. I doubt it would be much.

 

Well if you get the 87 octane from just the hose and nothing else then a 10' 1" fuel hose would put .4 gallons of 87 in your can before you get the 91.

 

So if your topping off your high octance sled or Quad directly at the pumps(drive up and fill your tank)......................Your not getting what you pay for?,,...Correct?
..........Caper...........

 

What if you only want 87 (or if you are here in Co 85) and the guy before you purchased 92 then what?????? LOL Just sayin. Not that big of a deal worry about over .5 to 1gallons worth of fuel and if it is dont buy such a small amount. The more you buy the better off your percentages are going to be!

 

P.S. another option would be to buy the 87 octane then add octane booster yourself!

 

The fuel that is left in the hose is a very minor amount.

How a Island is set up....each tank line comes up into the island, generally 3 grades of gas. Those 3 lines are connected to the pump/selector and each has a individual drain back valve. The line goes to the top of the island.

Once I'm done filling up with say 87...gravity takes any gas that's left in the line and it drains back to the holding tank...except the minor amount that's left in the hanging hose.

Some quick math.

Standard Hose ID = 0.675 inches
Radius = divided by 2 = 0.3375 inches
(12 Inches of standard hose)= 0.3375 x 0.3375 x 12 x 3.1415 = 4.29 cubic inches
1 gal. = 231 cubic inches
4.294/231 = .0186 gallons per foot of hose

A 10' hose contains at most.... 0.186 gallon of fuel.

If a guy is that worried about .186 of a gallon of say 87 octane...it's time to search out a individual high octane pump.

I'd be more concerned with high octane gas sitting in the tank for extended periods of time and lossing octane than I would the amount of fuel left over in the hose.

Wenty

 

Man, I'll tell you what, there is a lot of helpful people and good advice on this forum when you have a problem with your ATV. But Wenty has got his/her act together. Not only did he/she say how the pump works, he/she also gave us the amount of fuel in a hose and how he/she did it. I don't care what ya'll think that is awesome. you can't argue with the numbers.
John