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Xb9er
| | Posted on Saturday, September 04, 2004 - 05:51 pm: | 
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"Take a big tumbler of water... pour it into a gallon jug... fill the rest with milk... bet you could taste the difference between that with the water and a gallon that was not mixed down!"
Just wanted to point out that that is a bad analogy because we are talking about mixing gasoline and gasoline. Maybe skim milk and 2% milk???
Wykedflesh is right about the workings of gas pumps. Plus, pumps with vapor recovery systems suck the extra back up and into the storage tank, don't they? I don't think there is much more than vapors left in that hose unless you go right after someone who didn't wait and let all the liquid dribble out into their tank.
Crip2Nite -
Did there happen to be a tanker truck dropping off a load when you filled up? That can stir things up in that underground storage tank, and combined with a bad filter in the dispenser, you could get "dirty" gas.
If you are worried about lower octane left over in the hose, just let your buddy on the R1 fill up before you do.
Mike. |
BadS1
| | Posted on Saturday, September 04, 2004 - 06:46 pm: |
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Thanks Wycked and Xb9r you guys just explained what I didn't have to thanks guys. |
Crip2nite
| | Posted on Saturday, September 04, 2004 - 06:51 pm: |
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My wife rides a Honda Shadow Deluxe. I'll be a gentleman next time we both ride together and offer her the pump first!! |
Dasbuell
| | Posted on Saturday, September 04, 2004 - 07:25 pm: |
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I wouldn't think it would drain back when you shut the valve at the fill up nozzle. When you close that valve it stops the flow. If it drained back it would seem like that would cause inaccurate dispensing. I see it more like a straw in your soda glass. Put your thumb over the end of the straw and lift it up, and it holds the liquid until the vacuum is released. The valve at the filler nozzle would cause a vacuum and for it to drain back it would have to draw a greater vacuum inside the gas pump housing to pull it back.
Here is my theory as to how the pump works. If someone for a fact... like a gasoline pump tech can say better... this is my thoughts. Inside the big oh gadget that sucks money from my debit card is a system of plumbing feeding three grades of gasoline through a selection valve. To some degree it is always pressurized to keep things from draining down into the storage tank and causing inaccurate reading in the flow meter because of air in the system. Which side of the valve holds the flow meter I would guess is the feed line on each line to the selection valve. I speculate that valve is shut by a back flow preventing valve... or a one way flow valve... this would keep air and things from flowing backwards. Then you have plumbing to the upper part of the pump housing... and it might or might not have an in line filter. Someplace along the outer portion of the hose is a break-away fitting for those morons who drive off with the nozzle in their gas filler. That should only factor in if it is pulled away... and it prevents those cool gas station explosions in the movies. Then there is the fuel hose between there and the filler nozzle and sometimes an in line filter prior to the filler nozzle.
So... for the drain back to work... with the valve closed at the filler nozzle... the pump would have to draw a vacuum or reverse pump the gas back into the selection valve. That just makes no sense.
Next suspected comment or question... "So Das... if that is true... why doesn't gasoline come out of the filler nozzle when the pump is off and someone squeezes the filler valve?" Good question... for one... just like the soda straw example above there is a vacuum... and I bet in addition to that there is a check valve that beyond the filler valve squeeze handle, that actually requires fuel pressure to flow past that valve to prevent gas from draining out if the handle is squeezed and the line not pressurized.
AND... recovery systems of gasoline fumes I would think would not effect what I just speculated... as one is in a gaseous state... and the other is in a liquid state.
I selected water because milk is water based... coulda said skim milk... which in my opinion is not much more than water with white food coloring... LOL... it tastes like "white" water to me!
Any gasoline pump techs out there to factually fill in the blanks or flaws in my theory???
(formerly dasxb9s - still trying to think... and nothing is happening) |
Xb9er
| | Posted on Saturday, September 04, 2004 - 07:30 pm: |
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a gentleman. LOL
I forgot to mention that modern dispensers are designed to have as little fuel as possible left in the hoses above grade level for fire hazard reasons. If you drive off with the nozzle left in your car's tank, the hose is supposed to break away and not have fuel in it. If you plow over a dispenser, there is a breakaway valve below so gas won't spew out and cause a conflagration like in the movies.
An unrelated comment: Anybody see the movie Zoolander? Remember the gas station scene? That is so hilarious!!
Mike. |
Xb9er
| | Posted on Saturday, September 04, 2004 - 07:58 pm: |
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Actually, the mechanism that shuts off the pump when your tank is almost full works because of a vacuum in the dispenser nozzle.
And also, the multigrade blending pumps use only two grades of gasoline to make 3, 4 or 5 different grades of gas at the pump.
Of course there are still old pump systems out there depending on where you live and I am mainly referring to modern gas stations.
Mike. |
Dasbuell
| | Posted on Saturday, September 04, 2004 - 08:04 pm: |
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Is it that... or is there a valve on the hose/nozzle side of the breakaway that contains the gasoline IN the hose so what it STAYS in the hose... all remaining and contained so it can't escape and be a fire threat.. All it would take on the hose/nozzle side of the breakaway is a one way check valve that only allows flow under pressure toward the filler pump. The hose is supposed to break away and not LEAK fuel. There are many safety features in these system to prevent the movie type pyrotechnics.
Another thought to argue the fuel always stays in the lines (protected by check valves and one way flow valves to prevent movie like disasters). A flow meter designed to accurately measure a liquid... in this case gasoline... could not accurately deal with any air in the system... as air can be compressed and liquids can't... so any air that would be in the system at time would be compressed more than other times... and I think pumps do not work as well when there is air in the system... another reason to keep the liquid captured in the hose, plumbing and valving systems.
directional flow check valves make more sense than the gas pumped back into the system from the hose.
(formerly dasxb9s - my head still hurts from trying to think) |
Dasbuell
| | Posted on Saturday, September 04, 2004 - 08:12 pm: |
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I always thought it was because of back pressure being created my the air being expelled from your fuel tank... I don't see how there would be a vacuum when there is pressure pushing fuel out of the filler nozzle, and air being pushed out of the fuel tank as it is filled with the liquid.
(formerly dasxb9s - still have a gas problem) |
Wyckedflesh
| | Posted on Saturday, September 04, 2004 - 08:50 pm: |
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Das if you cut down on the beans your gas problem might go away.
OLDER pumps worked the way you mentioned. And if you recall the moment you started the pump and put pressure on the handle, fuel would flow. Have you noticed that now adays, you have to wait for the pressure to build in the hose BEFORE it will put pressure on the handle? Hmmm, if the fuel was remaining in the hose, then why wasn't there pressure already in the handle? |
Dasbuell
| | Posted on Saturday, September 04, 2004 - 09:22 pm: |
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There is some pressure always trapped between check valves... at a pressure below the minimum threshold of the check valve flow pressure... I would think... but not enough to over come the check valve that I would think works with the manual valve at the nozzle valve you squeeze... and the delay could be the system pressurizing from the flow pump building the pressure required to over come the one way flow check valve at the nozzle, after the display resets while I am stupidly standing next to my bike squeezing the handle and nothing happening... or at least what my thoughts would be.
What I have noticed... if I immediately squeeze the nozzle valve before all the displays reset... there was a delay before fuel flow. However... when I don't get in a hurry and don't squeeze the valve until the display resets... and I see the hose stiffen a bit from being pressurized... it flows immediately. Or so I seem to recall... ain't sittin at a pump right not to confirm my recollection!!!
(formerly dasxb9s - still full of beans) |
Dasbuell
| | Posted on Saturday, September 04, 2004 - 09:31 pm: |
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"Das... how can there be pressure between the check valves if you stated that only air compresses... and not liquid?" That is a good question.
The composite hose will stretch and the pressure is from the walls of the hose trying to return to the memory point before the pressure was applied. Much like brake hoses stretching under pressure to make the brake lever feel squishy... and how that happens less when metal braided brake line is used... less stretch of the brake line... therefore a more solid feeling brake lever. A liquid pushed at pressure... flexible composite hoses stretch under pressure.
(formerly dasxb9s - still my head hurts) |
Deerhunter17
| | Posted on Saturday, September 04, 2004 - 10:12 pm: |
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fuel pumps.. fuel pumps .. fuel pumps... Bull.... It ain't the pumps. Hot weather, and pis poor design. These bikes ping! Air cooled tech, new EPA standards, and "Technicians" who could care less... I am becoming less and less gratified with my HD powered Buell with each engine knock...I love the bike, I wish it had Engine technology that equaled its design. I can say that the HD product that my wife was looking to purchase just flew west!! |
Opto
| | Posted on Sunday, September 05, 2004 - 05:27 am: |
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All I can say is XB's ping when it's hot, and if someone reckons they don't, then they're not riding very hard, or it's not hot. I was disappointed to own a pinging Buell after head design and re-design going on since 1986. I retarded the timing approx 5 degrees from standard and the bike didn't like it very much at all, I'll put it back 2 or 3 and see what happens. Bottom line is the spark curve appears to be far from optimum. |
BadS1
| | Posted on Sunday, September 05, 2004 - 07:53 am: |
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Opto sorry bud but mine don't.And mine gets hot and it gets ridden hard enough. |
Dasbuell
| | Posted on Sunday, September 05, 2004 - 09:12 am: |
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My XB doesn't ping either... never has... and I don't baby it... in traffic I always have the engine around 5K... and take it up to the edge of the rev limiter on most shifts... never pings. Last summer it was 100+ several days of riding... did the same thing... and never a ping! A small portion of the time I will keep the revs down as not to disturb the normal people... still never a ping.
One last posting about my "30 oz theory" ya all have wore me out. AND this is ONLY to the point of mixing grades lowering octane.
Someone posted... to counter an earlier posting of mine... "Take a big tumbler of water... pour it into a gallon jug... fill the rest with milk... bet you could taste the difference between that with the water and a gallon that was not mixed down!
Just wanted to point out that that is a bad analogy because we are talking about mixing gasoline and gasoline. Maybe skim milk and 2% milk"
Here is a better one... try this and see if the difference can be noticed... by taste or color.
Take a big tumbler of chocolate milk... pour it into a gallon jug... fill the rest with white milk...
I am stopping now before I start getting hate mail from those bored with this aspect of thread hijacking!
(formerly dasxb9s - still a slow learner) |
Crip2nite
| | Posted on Monday, September 06, 2004 - 11:06 am: |
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3 days, over 600 miles...No more ping!!...Stopped using shared nozzles....I'm a believer!!! |
Opto
| | Posted on Tuesday, September 07, 2004 - 03:05 am: |
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OK, I should have stated "my XB12 pings with standard ignition timing, stock ecm, Drummer, K&N and snorkel removed, when it's hot and I get on it a bit between 3k and 4.5k rpm". It's much worse with the race ecm. |
