Gas stations with one pump for all grades?

[GTScort]

I've heard that if you go to a station with only 1 pump that distributes all 3 grades of gasoline, that your first gallon or so is whatever the guy before you pumped.

So you could be buying 93 octane, but if the guy before you was pumping 87, you're getting 87 until the lines are 'cleaned' and it starts pumping 93.

Anyone know if this is true? I've been going to this one station because it has 3 separate pumps for each grade. If I'm paying for 93, I want 100% 93.

 

[Reg# 43897]

Oh yes, it's quite true. Nothing you can do about it other than to see what the last guy pumped... or choose another pump. All you can do is finish off your tank by stopping that same pump, re-setting it for regular and starting it again to complete yor fill-up. Pretty anal way to go about it in my opinion. I avoid those stations like the plague. Not so much of an issue with a large tank but it ****** me off with my bike or sled, let me tell you.

John.

 

[k1xv]

This is quite common around here in Vermont, one hose and nozzle, and you press the button for the grade you want.

Also, the Sunoco pumps have always been like this.

At least they don't try to combine gasoline and diesel pumps with one hose!

 

[labman]

Say the hose is 3/4 ID and 10 feet long. 3/8 X 3/8 X 3.14 X 120 = 53 cubic inches. 53 cu in/ 231 cu in/gal = 0.229 gallon. Likely each tank has its own pump with with the selector valves near where the hose connects. Likely the volume is measured with some sort of mass flow sensor in today's electronic pumps. So I would guess that at least the first quart that comes out is the last stuff, and maybe more, about twice as much if the hose is an inch ID. Look at the hose, the ID may be in sixteenths, 12 or 16 as part of the part number. Some stations have separate hose for each grade. Might be a big factor in choosing stations if you use premium.

 

[sifan]

The Chevron gas station in Maryland has this 1 pump setup, too. Since I only use 87 octaine, you mean I might occassionally get extra Techron from the premium gas in this way?

 

[Bryanccfshr]

With that little volume I am not going to stress over it. I have never actually considered it a problem and still do not. If you pump 15 gallons of 93 premium and in a worst case scenario you have a full gallon of 87 grade residual in the hose(that's allot of 3/4" hose) you will end up with an average of 92.6 octane. That is within the normal variance in pump gas anyhow.

 

[Rob Taggs]

Thats the way about half the gas pumps in Kansas are too. Would only bother me if I had a high dollar car that required high octane.

 

[sifan]

GTScort - Yeah, we should get what we pay for especially in today's high gas price. Maybe you can print out a copy of this thread and show it to the owner of the gas station with one pump next time, and ask for a free cup of coffee just to make it up to you.

 

[Jelly]

Sure, your fuel is gonna be somewhat diluted on paper, but is this really that big of a deal?

I used to ride around on a Honda motorcycle that required premium unleaded to run properly. It had a three gallon fuel tank (which means I had a much larger percentage of regular unleaded in my premium in comparison to your car), and even with the "dilution", I had no problems...

 

[TallPaul]

When I was a kid, I remember being nearly out of gas. It was late and we pulled into a closed gas station and drained all the hoses into my tank.

Not sure how much it helped but I got home.

 

[GTScort]

quote:

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Originally posted by TallPaul:

When I was a kid, I remember being nearly out of gas. It was late and we pulled into a closed gas station and drained all the hoses into my tank.

Not sure how much it helped but I got home.

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LOL yup.

actually everytime I put gas in my car, I'll turn the pump off at whatever dollar amount I want, and then squeeze the handle 5-10 times till the hose is clear so I get that extra gas.

If everyone were to do this, the pumps would be clear of the previous fuel and everyone would get the octane they paid for.

 

[Patman]

That's another reason I like using Shell over Esso up here, is that Shell does have a seperate pump for their 91 octane, while all Esso stations have the "three in one" design.