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-   -   ARTICLE: How to get the maximum Fuel Efficiency (https://www.team-bhp.com/forum/owning-car/17748-article-how-get-maximum-fuel-efficiency-32.html)

I genuinely beleive that Fuel efficiency is an over rated topic in our country.I'm surprised that a lot of our fellow citizens harp on "mileage" rather than safety and driving pleasure.
Having said that,if we follow the basic rules of driving,it will automatically result in better fuel efficiency.
Avoid Clutch driving,dont over speed,reduce the usage of hard braking.
I make it a point to turn of my engine at signals..Believe me,it helps.

I have never turned off my engine at a red light. Weird fear of not being able to start again..... I am not sure how much i get from the Palio since the odo stopped working at 3 K. But Rs. 500/- worth of "extra premium" gets me from Belapur to Fort, Gateway, Worli Seaface through Marine Drive and Peddar Road and back with the AC on all the way. So I am guessing its doing okay.

Anyway, I was driving the linea (Petrol) and noticed something peculiar - The instant consumption which normally shows between 12 mpl to 15 mpl at 2k rpm to 3k rpm had jumped up to around 18-20 mpl at speeds around 160 km/h. Can't remember exact rpm. This was on the expressway. I can't figure out whether driving at excessively high rpm gives better FE, or whether the display was selling me snake oil.

Can anyone confirm this phenomenon and the accuracy of the "Instant Consumption" figure?

I have a question that relates to fuel efficiency with respect to air conditioning. Does vaying blower speeds increases/decreses fuel efficiency when the AC is on? Also, does increasing or decreasing the amount of cooling (the blue meter on AC console) has any impact on fuel efficiency?
Or there are just two standards. AC on and AC off?

You got that last statement right, there are only two standards, off and on which keeps the compressor running or not !

The blue meter on AC console is the temperature thermostat. If you set it to extreme left i.e. completely turned to blue side, the compressor will operate for longer duration as you have set lower temperature and vice-versa. Even when the AC switch is ON, it is not necessary that compressor will operate continuously. It automatically turns off and on depending on temperature set.

Good point bluevolt, I should have additionally mentioned that in my post above !

There is no thermostat/temperature setting in the lower end cars such as Alto or Santro. The compressor cuts off when a certain level of ice build-up is detected, that is all. Similarly, when we set a higher temperature level, temperature is maintained just by operating the heater concurrently with the Ac.

The FE advantage gained in my Alto with the AC on/off is just 2 KMPL in city and 1 KMPL on the highways.

@Gansan, how much does your Alto give in city and highway with AC on ?
My friend says his Alto gives 14 and 19 respectively. The city FE being on lower side, but I noticed that he keeps shifting gears continously, which could be a reason.

I have noticed with many readings over many months, it is 14/16 in the city and 21/22 on the highway.

I would say the highway figures are more accurate, as the calculation is done in a single day (Pondy and back). They have been consistent over five - six trips. I fill the tank while starting out, and will top-up in the same nozzle in the same Shell station on my way back.

There may be some evaporation loss in the city readings as I take the car out only once or twice a week, and rest of the time it is parked OTS though with a cover on. I calculate once a month when I top-up the tank, and take the average of 4 - 5 readings.

But most of my city drives take place in smooth moving, not bumper to bumper, traffic. I can drive at least in fourth, if not fifth, gear.

Edit:The figures indicate FE with ac on/off. And yes, I also shift through the gears liberally to keep in the power band, a practice carried over from using the Splendor!

My car is giving an average of just 9-10Km/lit.

I recently got 2007 1.4 Ford Fiesta, 53000KM (Pre-owned)
Previous owner was a car enthusiastic & keep this car like his baby.

1st I got the car serviced at ford & changed all the fluids.
- Synthetic Engine Oil Mobil
- Flushed & refiled coolant, steering oil & brake oil
- New Air filters
- Serviced AC, new gas, compressor oil etc.
- New tyres Michelin XM1 +

Still I am getting really low mileage when compared to other fiesta ( some reported 16km/lit on highway). I have not plugged in any diagnostic cable to check for any malfunction. Most of my driving is on open roads, but more or less I get the same mileage in traffic.

Can we suspect spark plugs, clutch or is it something else?
Please advice.

Mileage will vary depending on a lot of factors like driving style, traffic conditions, engine/car conditions etc.

Did you try calculating the FE on a highway (to compare with the 16 kmpl that you have heard from people)?

Just have a check at the fuel filter in case it is clogged. Is the air pressure correct?

I'd suggest you have an open run on a highway and use a different fuel station and check.

If the 16 kmpl that you have found is correct, the difference is way too drastic.

Is this a petrol or diesel?

Thanks libranof1987,

I agree about the style & other conditions, I have done like 600kms till now with 1000k refill each time. I drove in traffic & open roads the difference is not much, 16lit last me just 150-160kms.

16km/lit is the max I have heard, I don't mind even if I achieve 12-14.
Air pressure is optimal, I was thinking of checking my spark plugs & fuel filter.

@kiku007 Mine is Petrol.

@Siddharth, the Fiesta never came in 1.4 petrol. Either you have a 1.4 Diesel or a 1.6 petrol. If it is a petrol, then the FE is okay-ish. If diesel, then it is on the lower side.

1. Check where you get you diesel from. Try another bunk.
2. Check air pressure in your tyres. Very likely cause of lower FE. Try increasing it by 1-2 psi.
3. Correct way to measure FE in cars : top-up to top-up. Fill it all the way to top where you can see the fuel in the tank inlet, drive around, and again fill up to the same point.

From what I have seen and heard from friends its usually around +2 kmpl without A/C in most cars. Very true for most marutis.