On social media, there are a few theories relating to refuelling a car. One of the more popular ones is that when fuel is pumped at a fast rate – when the handle on a fuel nozzle is depressed completely – you’ll actually get less fuel than what you paid for.
This theory arose due to the claim that petrol more easily vaporises and is “lost” into the air when pumped at a fast rate. As such, it’s been suggested that pumping petrol at a slower rate minimises this loss, but is this fact or fiction? Are people wasting more of their time and of others by refuelling slowly at the pumps?
To put the theory to the test, Shell Malaysia Trading managing director Shairan Huzani Husain, who is also known affectionately as “Pak Cik Shell,” uploaded a video to his personal Instagram account featuring a self-made experiment.
In the video, Shairan used a volume gauge to measure the amount of petrol coming out of a fuel pump, which was set to deliver 10 litres of RON 95 petrol. The experiment involved first pumping the fuel at a slow rate, followed by another round at a much faster rate. On both occasions, the end result was the same, with the gauge showing 10 litres delivered.
However, it should be noted that fuel evaporation when refuelling can be affected by temperature and weather factors, although the difference in volume is miniscule. Based on the experiment, it looks like there’s no real benefit to refuelling slowly, especially when others are waiting for their turn.
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You can use the clip on the trigger instead.
Not slow enough for some…
Fully depressing the handle on a fuel nozzle made no difference.
But fully depressing the fuel throttle , got big difference.
Can we also have another video from Pakcik Shell to debunk the stupidity from down south that rocking the car would allow for more fuel to go in?
good point bro
For EV, rocking the car would allow for more karan to go in.
If you pump a full tank of fuel at a fast flow rate, the process will create little air pocket in your fuel tank which will take some time to dissipate out (this doesn’t mean you are getting less fuel from the pump), rocking the car will help to remove these air pocket, thus having little extra space to fill up more fuel.
Why would you want to pump fuel in a full tank? Full ardy mah, stop the pump, pay your money and go lah, long Q at the back waiting for you to finish. Aiyooo…
Copy paste: “However, it should be noted that fuel evaporation when refuelling can be affected by temperature and weather factors, although the difference in volume is miniscule. Based on the experiment, it looks like there’s no real benefit to refuelling slowly, especially when others are waiting for their turn.”
There’s really no need to fill up until the brim of the filler neck to get a full tank because the fuel will then occupy the space in the filler pipe between the neck & the actual tank. Usually when the dispenser pump nozzle stops automatically, that would mean the tank itself is already full.
Do you know how teh tarik got the signature foam at the top?
Singaporeans do this a lot.
I have to fuel slowly cos the Merc A Class has a complicated piping which overflows easily if i depressed fully at full speed.
Anyone else experience this ?
If you see a guy holding the nozzle at the fuel pump beside a merc than please know its because the cars fault
Not for GLC tho. Pumped as fast as i can
My persona is having the same issue..Kancil also suffer from this..Might be the filler neck design is slightly out. however the Persona is slightly better..
my 1996 toyota has the same issue with some pumps when I pump fast. Looks like the ‘neck’ is too small to let it flow in fast.
Same bro. Owns a 2014 A200. Turns out the problem is the charcoal canister of the tank (mechanic replace that, I didn’t really understand how it works), can pump like normal now after replacement of the said item.
Not for my s class and all BMW. Yours defect. Go check up.
So folks, refuel your vehicle and get tf outta there ASAP especially during peak periods.
Malaysians are gullible lot for anything, even unbelievable fantastical but empty promises. I’m not surprised they’d willing to sacrifice their first born son for riches if the internet sez so.
Shell’s pump no much different when you depress it full or not, I think they set the pressure higher and their pumps are really quick if you are on a rush. Most of the time I go to Caltex or Petronas which I felt the pumps are lower in pressure and pump slower. Personally I felt that Shell’s fuel does not last very long in my tank as well, perhaps I drive old car lah.
You are right. I felt the same and I was amused by the same feeling. Now that you mentioned it, I feel like what is going on!
Well, guess it’s just science and placebo.
Like someone said, the faster you pump the more air bubbles formed. So if you pump full pressure then you would think you have a full tank but actually is air. So perasan cepat habis.
But the video is not conclusive…they didn’t show the amount dispensed by the pump. So maybe tipu gak pakcik shell ni!
The bubbles do not affect how the machine measures fuel volume. The metering system does not work with gases. Even if half – in volume – of what you pump is air, then the machine would simply have to pump twice as long to deliver the correct amount of liquid fuel.
During the 80’s kiosk with old type of pump gauge, not yet digital. That kind of pump when you depress lightly fuel will dispense but the dial remain still.
Used to work at this kind of pumps and making money every day untill boss found out why those bike take longer time to fillup. Haahaa…free ride everyday.
Ustaz melarang kami mengambil hak orang lain …
I would prefer to hear from an automobile engineer on this as they would know the difference between the two. Not sure if the tank is designed to have a wider depth at filling pipe end than at the opposite end creating more head space for air to escape through filler pipe.
According to 1 engineer there should not be any difference as pump metering system are certified by regulators. Evaporation is minimal as fuel nozzles are inserted into the inlet pipes during filling so less exposure to atmosphere. Car fuel tanks have breather pipes to vent air above inflowing fuel so chances of air traps is nil. I stand to be corrected!
For me, the best person to answer this question is mechanical engineer who specialize on calculation of liquid flowrate.
Even if there is air pockets in the fuel system when fueling fast, is your time worth so little that you would waste it? Assuming 1% is air, and you pump $100. That is only Rm1 lost. Is your time and effort really worth so little?
Can you do debunking of this guy with so called hand held ron tester going around testing 97 in plastic bottles?