Fuel Tank Capacity - Version 2
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From: Colorado Rocky Mtns.
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From: Westchester County, NY
'11 E550 4MATIC, '07 Suzuki SV1000S
Where did the extra gas go?
Found this on the web somewhere - don't know if it would account for a 1+ gallon loss but it is interesting reading. I definitely know from my work as an auditor - I had an oil co as a client - doing inventory it very important to note the temperature of the fuel in the storage tanks at the bottom, middle and top of the tanks, as well as measure the amount of water in the tanks...it all gets calculated to determine how many gallons are in the tank...on any given day it could swing by quite a bit - with no movement of inventory - just shifts in tempaerature.
Vapour recovery, (removing petrol vapour from your tank as you fill) does reduce the amount of fuel you have bought. We commissioned one of the first filling stations with vapour recovery, (installed mainly to passify local residents who didn't want the smell of petrol) after four weeks we switched the vapour recovery off to see if the locals would notice the difference. They didn't but surprisingly the tank gauge leak alarms went off on all tanks because they weren't getting the input from the condensed fuel vapour and so showed a loss!
We had one operator who had a couple of hundred filling stations, he always made fuel deliveries in the hottest part of the day and within hours we had to attend to see where several gallons of fuel had gone to. The site operator had dipped the underground tank before and after the delivery and dipped the road tanker before the drop but immediately noticed that the underground tank dip didn't show the same amount of fuel after the delivery. The loss was due to cooling when the warm delivered fuel mixed with the cold product in the ground. The fuel in the underground tank will continue to shrink in volume for a few hours after a delivery so keep your eyes open when looking to fill up your car.
'Splash fills', where the fuel hits the fuel in the underground tank pushing a pipe full of air immediately stirs up the sediment and causes masses of bubbles in the tank which turn to vapour. You can actually see the vapour pouring out of the vent stack when this happens so the same thing obviously occurs in your car tank.
Not opening the nozzle fully takes longer but does give you more fuel! When carrying out measure checks on the pumps we always did fast and slow 40 litre measures. Some flow meters leak a tiny amount of fuel past the piston under pressure so a slow flow gives the proper measure of fuel and a small bit of leakage. If you open the nozzle to full flow the meter seals are under minimum pressure so you get exact measure and the rush of fuel into your petrol tank will raise maximum amounts of vapour which will escape into the atmosphere or be sucked back to the underground tank by the vapour recovery system - 'thank-you very much'. It usually pays to always use the pumps nearest the kiosk. They get most useage so their meter seals wear fastest.
Flow meters are set at exact measure then a seal is fitted to stop any tampering with the setting. Unfortunately some meters then wear in and start to give reduced measures after a few weeks. Other meters will start to give fuel away after a few weeks so it pays to shop arround and note where you get the best volume/mileage results. The difference between meters can be as much as 5 litres on a full tank!
Not many people are aware that there are Winter and Summer grade fuels. The difference can be sufficient to prevent the Winter unleaded fuel being pumped from the underground tank in warm weather. Believe me this has happened. We tried everything from a replacement petrol pump to fitting temporary above-ground suction pipes without success. Finally we dropped a few thousand gallons of Summer grade unleaded into the tank and the tanker was then able to extract the mix and take it away for treatment. In very hot weather when pipes run just below the forecourt surface the fuel can cavitate and comes out of the nozzle in fits and starts. The air separator in the pump should remove the gas but might let some through.
Another legal 'tweak' I have seen is with blended fuels. Usually the 2* and 4* fuels, when mixed 50/50% give a legal octane rated 3*. If the 4* fuel has a high octane level then you can alter the mix to give as much as 75% of 2* and still stay legal!
In Conclusion:
Petrol is very volatile and will evaporate away rapidly especially if you heat it or stir it up, the rate of loss will increase dramatically. So think carefully when you handle it - its too valuable to waste.
Vapour recovery, (removing petrol vapour from your tank as you fill) does reduce the amount of fuel you have bought. We commissioned one of the first filling stations with vapour recovery, (installed mainly to passify local residents who didn't want the smell of petrol) after four weeks we switched the vapour recovery off to see if the locals would notice the difference. They didn't but surprisingly the tank gauge leak alarms went off on all tanks because they weren't getting the input from the condensed fuel vapour and so showed a loss!
We had one operator who had a couple of hundred filling stations, he always made fuel deliveries in the hottest part of the day and within hours we had to attend to see where several gallons of fuel had gone to. The site operator had dipped the underground tank before and after the delivery and dipped the road tanker before the drop but immediately noticed that the underground tank dip didn't show the same amount of fuel after the delivery. The loss was due to cooling when the warm delivered fuel mixed with the cold product in the ground. The fuel in the underground tank will continue to shrink in volume for a few hours after a delivery so keep your eyes open when looking to fill up your car.
'Splash fills', where the fuel hits the fuel in the underground tank pushing a pipe full of air immediately stirs up the sediment and causes masses of bubbles in the tank which turn to vapour. You can actually see the vapour pouring out of the vent stack when this happens so the same thing obviously occurs in your car tank.
Not opening the nozzle fully takes longer but does give you more fuel! When carrying out measure checks on the pumps we always did fast and slow 40 litre measures. Some flow meters leak a tiny amount of fuel past the piston under pressure so a slow flow gives the proper measure of fuel and a small bit of leakage. If you open the nozzle to full flow the meter seals are under minimum pressure so you get exact measure and the rush of fuel into your petrol tank will raise maximum amounts of vapour which will escape into the atmosphere or be sucked back to the underground tank by the vapour recovery system - 'thank-you very much'. It usually pays to always use the pumps nearest the kiosk. They get most useage so their meter seals wear fastest.
Flow meters are set at exact measure then a seal is fitted to stop any tampering with the setting. Unfortunately some meters then wear in and start to give reduced measures after a few weeks. Other meters will start to give fuel away after a few weeks so it pays to shop arround and note where you get the best volume/mileage results. The difference between meters can be as much as 5 litres on a full tank!
Not many people are aware that there are Winter and Summer grade fuels. The difference can be sufficient to prevent the Winter unleaded fuel being pumped from the underground tank in warm weather. Believe me this has happened. We tried everything from a replacement petrol pump to fitting temporary above-ground suction pipes without success. Finally we dropped a few thousand gallons of Summer grade unleaded into the tank and the tanker was then able to extract the mix and take it away for treatment. In very hot weather when pipes run just below the forecourt surface the fuel can cavitate and comes out of the nozzle in fits and starts. The air separator in the pump should remove the gas but might let some through.
Another legal 'tweak' I have seen is with blended fuels. Usually the 2* and 4* fuels, when mixed 50/50% give a legal octane rated 3*. If the 4* fuel has a high octane level then you can alter the mix to give as much as 75% of 2* and still stay legal!
In Conclusion:
Petrol is very volatile and will evaporate away rapidly especially if you heat it or stir it up, the rate of loss will increase dramatically. So think carefully when you handle it - its too valuable to waste.
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Hey Jack... great to see that you still lurk here. Hope you are doing well too.
I think Valero's pumps are okay. I know that I was running on fumes. I have never been so glad to see a gas station in my life. In addition, I had never seen the fuel guage actually go completely horizontal at the empty mark.
I think Valero's pumps are okay. I know that I was running on fumes. I have never been so glad to see a gas station in my life. In addition, I had never seen the fuel guage actually go completely horizontal at the empty mark.
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From: Scottsdale, AZ
2004 RX330, 2008 Scion xB, 2001 Honda Insight Hybrid, 2010 Toyot Prius v ATP
No, I was not trying to out-do anyone. And it's the second time it's been this high, from completely different locations, so it's not a malfunction. Oh, and the needle was on "E" but not way below it or 100 miles past the fill-er-up icon on the "range" screen. So, using Kent's filling technique, you can put one hell of a lot of kerosene in these puppies, even on a hot day.
STP
STP
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Mercedes Gas Tanks are Blivits
Putting 30 gallons of gas (or kerosene) into a tank with a capacity of 28 gallons means MB is providing Blivits for their gas tanks.
FYI, a Blivit is a term used in the Navy which describes the feat of loading 2 pounds of S*** in a 1 pound bag....
FYI, a Blivit is a term used in the Navy which describes the feat of loading 2 pounds of S*** in a 1 pound bag....
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From: NW corner of CONUS
2008 GL 320 CDI, 2004 VW V10 Touareg TDI
And is that what was on my porch when the doorbell rang the other day?
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2011 E350 Cabriolet..White and Almond Mocha
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From: Scottsdale, AZ
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From: Omaha, Nebraska
'08 GL 320 CDI (scheduled delivery 3/20/08)
29.1 gallons....while on my way to California filled up in Denver, CO and made it all the way through Las Vegas, NV. 761 miles with about 35 minutes of nail biting towards the end while visions of the flat-bed tow truck were flashing before my eyes while trying to find a diesel station.
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From: Scottsdale, AZ
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I have my truck back and I just did another fill up with about 1/16th of a tank, of over 30 gallons. (PS Safeway about four miles from me had the dark stuff at $2.88/gal, and with their loyalty card it was $2.85/gal - around my house it's going from $3.05-$3.15!)
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I fill to the first stop (provided it appears to have filled at least near what I expect it to do), then wait for about 10 seconds. Then I sqeeze the nozzle on as slow a setting as I can manage. It'll foam up, and as it approaches the top you have to stop and wait a bit. There will come a point where a very light squeeze will keep the level about where you can see it but stopping lets the level drop. I actually either hold the nozzle against the top of the filler or touch the rim on the outside to feel when the vibrations/bubbling stops. When it does, I go back to the super-slow fill until I either get foam again or fluid again. If it's fluid, I usually stop at that point. It adds about 3 minutes to the fill-up, and between 3-4.5 gallons (US) to the tank.
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From: NW corner of CONUS
2008 GL 320 CDI, 2004 VW V10 Touareg TDI
I've seen drawings of the diesel fuel tank for the 320s. The tank has three 'turrets' that trap air when you are filling. Each of the three has a vent tube at the top that is connected to the main filler tube a few inches below the top. You will notice that, in addition to the foam in the filler neck, you will see a 'bubbling' when the liquid level gets above the vent tube connection. When that bubbling stops and you can see the liquid level, all the air and foam in the turrets has gone away. At that point the liquid level in the filler tube will drop very slowly if at all. When that happens you are done.
I have noticed 3-4 gallons difference between first click off and absolute full.
I have noticed 3-4 gallons difference between first click off and absolute full.
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15 GL550
STP and Fourdiesel, thanks for the info. I get a free tank up to 30 gallons about every third fill up at the Grocery owned station. If I can figure this out without spilling diesel down the side of my GL I'll save a few extra bucks when I cash in my Fuelperks.
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From: NW corner of CONUS
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