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Old 1st January 2015, 16:32   #4336
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Default What is your Actual Fuel Efficiency?

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Originally Posted by recshenoy View Post
interesting. So early fueling can help in getting better FE? Possibly due to car completing 20K and engine opening up.



By the way how accurate are analog fuel gauges in cars, say 25% indication on fuel gauge always corresponds to X liters of fuel?

I doubt very much that early fueling will improve FE. in fact I would say it makes it worse, because the average weight of the car remains higher. just a little bit but still. Weight always carries a fuel penalty. If the FE has increased it must be due to the other factors mentioned.

Analog gauges can be notoriously unreliable. On my Mercedes and Jaguar the needle wont move hardly at all for the first 100-150 KM after filling up. On my wife's Fiesta it is pretty reliable across the full scale. You just need to try it out and get a feel for it.

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Old 1st January 2015, 17:15   #4337
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Default Re: What is your Actual Fuel Efficiency?

Quote:
Originally Posted by recshenoy View Post
interesting. So early fueling can help in getting better FE? Possibly due to car completing 20K and engine opening up.
Quote:
Originally Posted by Jeroen View Post
I doubt very much that early fueling will improve FE.
I started early filling, after reading that when fuel level is low, the fuel pump has to work hard - not sure about the "how"s.

Quote:
Originally Posted by Jeroen View Post
in fact I would say it makes it worse, because the average weight of the car remains higher. just a little bit but still. Weight always carries a fuel penalty.
The extra weight may be an average of 20KG (assuming a 40L fuel tank), which will not make too much of a difference. 4 extra persons in the car will cause an additional weight of around 200-250KG!

Quote:
Originally Posted by recshenoy View Post
By the way how accurate are analog fuel gauges in cars, say 25% indication on fuel gauge always corresponds to X liters of fuel?
Yes, it may not be that accurate. But I check it during every filling. On an average, it gives me 21-22KMPL now. I follow the following steps to calculate FE:

1.Reset a trip meter to 0 when the fuel needle is at the second position (25% line).
2. Fill 20 liters of Petrol.
3. Drive in a sedate way; trying to make the instant FE figure showing 30KMPL as far as possible
4.Note the trip meter reading when the fuel needle is again back to the second line.
5. Divide distance shown on trip meter by 20.

Last edited by romeomidhun : 1st January 2015 at 17:21.
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Old 1st January 2015, 19:31   #4338
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Originally Posted by romeomidhun View Post
I started early filling, after reading that when fuel level is low, the fuel pump has to work hard - not sure about the "how"s.
.
The effect of a full compared to a low tank on the fuel pump power consumption is negligible.

[quote=romeomidhun;3613818
The extra weight may be an average of 20KG (assuming a 40L fuel tank), which will not make too much of a difference. 4 extra persons in the car will cause an additional weight of around 200-250KG!

Yes, its small, probably negligible, but it is still very real. Whereas increasing FE due to early filling isn't.
Jeroen



.[/QUOTE]
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Old 1st January 2015, 20:12   #4339
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Default Re: What is your Actual Fuel Efficiency?

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Originally Posted by Jeroen View Post
The effect of a full compared to a low tank on the fuel pump power consumption is negligible.
Somehow, it happens!

Source: http://mpg50.com/fuel_saving_tips.php

"One of the most important tips is to fill up when your gas tank is just half full (or half empty). The reason for this is, the more gas you have in your tank the less air occupying its empty space."



Source: http://www.wikihow.com/Increase-Fuel-Mileage-on-a-Car

"When you fill up with gas, fill up halfway and try and keep your tank above one quarter full. If your fuel runs low,you could put stress on the fuel pump."
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Old 1st January 2015, 20:54   #4340
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Quote:
Originally Posted by romeomidhun View Post
Somehow, it happens!

Source: http://mpg50.com/fuel_saving_tips.php

"One of the most important tips is to fill up when your gas tank is just half full (or half empty). The reason for this is, the more gas you have in your tank the less air occupying its empty space."



Source: http://www.wikihow.com/Increase-Fuel-Mileage-on-a-Car

"When you fill up with gas, fill up halfway and try and keep your tank above one quarter full. If your fuel runs low,you could put stress on the fuel pump."

Hogwosh! Don't believe everything you read on the internet. Calculate the difference and you will find it is negligible.
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Old 2nd January 2015, 09:45   #4341
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Quote:
Originally Posted by romeomidhun View Post
I started early filling, after reading that when fuel level is low, the fuel pump has to work hard - not sure about the "how"s.



The extra weight may be an average of 20KG (assuming a 40L fuel tank), which will not make too much of a difference. 4 extra persons in the car will cause an additional weight of around 200-250KG!



Yes, it may not be that accurate. But I check it during every filling. On an average, it gives me 21-22KMPL now. I follow the following steps to calculate FE:

1.Reset a trip meter to 0 when the fuel needle is at the second position (25% line).
2. Fill 20 liters of Petrol.
3. Drive in a sedate way; trying to make the instant FE figure showing 30KMPL as far as possible
4.Note the trip meter reading when the fuel needle is again back to the second line.
5. Divide distance shown on trip meter by 20.
Keep refueling at 25% mark, but do a tank ful 2 consecutive times to calculate FE using the tankful method, the most accurate one. My old shape 1.2 k series Swift gives 13 in city and 15 on highway. Thats it. Yours is just too good.





Quote:
Originally Posted by Jeroen View Post
Hogwosh! Don't believe everything you read on the internet. Calculate the difference and you will find it is negligible.
Romeomidhun is already reporting a difference by refueling early. I too doubt it being the reason, hence advised him to use the tankful method instead, but if somebody is reporting a differnce, I would tend to believe what is written on those webpages.
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Old 2nd January 2015, 09:59   #4342
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Default Re: What is your Actual Fuel Efficiency?

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Originally Posted by me@fiat View Post
Another example of magical FE from my side...

- Model FIAT Grande Punto, emotion pack, 75Hp, Diesel, Sept 2009
- Pune to Panvel Expressway,
- 4 adults + 1 kid on-board
- Packed trunk
- 40% AC
- Cold weather
How much mileage does you Punto give in highway?
My punto gives me only 15kmpl in the highway and my average speed is 120kph. I'm worried because many say that they get atleast 18 kmpl. Wonder if I'm missing anything.
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Old 2nd January 2015, 10:26   #4343
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Default Re: What is your Actual Fuel Efficiency?

Got 18kmpl on my recent drive to Nellore from Hyderabad. (XUV500).

Speed: 80-85kmph
AC: 24 degrees Economy
Two people on board and negligible luggage
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Old 2nd January 2015, 18:33   #4344
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Default Re: What is your Actual Fuel Efficiency?

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Originally Posted by madroxx View Post
How much mileage does you Punto give in highway?
My punto gives me only 15kmpl in the highway and my average speed is 120kph. I'm worried because many say that they get atleast 18 kmpl. Wonder if I'm missing anything.

I guess it is your 120+ speed that eats away the mileage !
I suppose the ideal speed for the maximum FE should be around 80-90 Kmph and anything more shall take its toll on the fuel !
If you maintain these speeds , I am sure the FE shall ascend!
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Old 2nd January 2015, 18:59   #4345
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Quote:
Originally Posted by itsashishsharma View Post

Romeomidhun is already reporting a difference by refueling early. I too doubt it being the reason, hence advised him to use the tankful method instead, but if somebody is reporting a differnce, I would tend to believe what is written on those webpages.

I am willing to learn, but if I dont understand it or can't make sense of it I will challenge it and I would be very happy to learn something new. But the notion about the fuel pump being the cause of poorer FE when the tank level drops is beyond my comprehension of understanding. So unless somebody explains why that would happen I don't buy it.

Jeroen
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Old 3rd January 2015, 08:43   #4346
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Quote:
Originally Posted by Jeroen View Post
I am willing to learn, but if I dont understand it or can't make sense of it I will challenge it and I would be very happy to learn something new. But the notion about the fuel pump being the cause of poorer FE when the tank level drops is beyond my comprehension of understanding. So unless somebody explains why that would happen I don't buy it.

Jeroen
Even I don't get it. But if you are so willing to learn, why did you discard it when he shared those 2 URLs? Did you read the articles? If you didn't, you are not willing to learn. Well, if yiu did, please share with us what do you understand about those. If a fellow teambhpian is reporting something and to support that, even URLs are being shared, one should not just discard, asking for not to believe everything on tge internet.
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Old 3rd January 2015, 15:31   #4347
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Default What is your Actual Fuel Efficiency?

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Originally Posted by itsashishsharma View Post
Even I don't get it. But if you are so willing to learn, why did you discard it when he shared those 2 URLs? Did you read the articles? If you didn't, you are not willing to learn. Well, if yiu did, please share with us what do you understand about those. If a fellow teambhpian is reporting something and to support that, even URLs are being shared, one should not just discard, asking for not to believe everything on tge internet.

Let me put my life on hold as somebody on the internet is wrong!
The tips in those two URLs are fine, except the one about stressing the fuel pump when the level in the tank is low. Just rubbish.

Fuel pumps are positive displacement pumps, mostly placed at the bottom of the tank, or beneath it, so largely gravity fed, and even if they are not, as they are PD pumps it will still work fine.

And my advise not to believe everything you read on the internet is very sincere. Just because you never heard of something, or you see new information you don't understand doesn't make it true.

Last edited by Jeroen : 3rd January 2015 at 15:40.
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Old 3rd January 2015, 18:10   #4348
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Default Re: What is your Actual Fuel Efficiency?

Ford Figo 1.2, fully loaded with 4 adults and luggage.
Highyway trip of 800 Kms with speeds exceeding the ton very rarely and AC running almost whole distance.
FE: 13.2 kmpl
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Old 3rd January 2015, 18:38   #4349
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Chevrolet Beat TCDI 0-1000 kms report.

I drive 90% of the time single and due to winters AC is not required in Delhi-NCR. 70% inner city roads with no super heavy traffic all the time and 40% on highway. Car gives over 20 kmpl easily when driven under 80 kmph. As I was running-in the new engine, didn't push her too hard.
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Old 3rd January 2015, 19:46   #4350
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Default Re: What is your Actual Fuel Efficiency?

Quote:
Originally Posted by romeomidhun View Post
Somehow, it happens!

Source: http://mpg50.com/fuel_saving_tips.php

"One of the most important tips is to fill up when your gas tank is just half full (or half empty). The reason for this is, the more gas you have in your tank the less air occupying its empty space."



Source: http://www.wikihow.com/Increase-Fuel-Mileage-on-a-Car

"When you fill up with gas, fill up halfway and try and keep your tank above one quarter full. If your fuel runs low,you could put stress on the fuel pump."
These have a grain of truth.
. Dirty air filter does decrease FE.
. Colder fuel weighs more, so you are getting more for your money.
. The more air there is in the tank, the faster the fuel evaporates. I have seen similar discussions for the past 50 years, and it is true. During North Indian summer when the temperatures rise above 40 degrees, you may find a significant reduction in FE if you fill fuels after a long period - 10 days+. I have experienced a much lower FE when the car is idle for a couple of weeks in summer.
. Higher tyre air pressure reduces the foot print, which in turn reduces the rlling resistance and increases FE. All vehicles which enter "FE" rallies use thin tyres inflated to extremely high pressure.
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