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Old 30th January 2020, 09:05   #736
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Default Re: Ertiga Low Mileage Issue

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Originally Posted by guruji View Post
My ertiga has crossed 1L km recently and i am observing a drop in mileage these days. now I have to go through quite heavy traffic. how low the fuel efficiency can drop? I am seeing 10Km/l
Ten kmpl is not bad mileage for high traffic driving. I presume your AC is on and you are primarily running no higher than 3rd gear.

A good pointer would be to test some other car(eg. DZire/ Swift), running on the same fuel under similar conditions.
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Old 30th January 2020, 09:14   #737
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Default Re: Ertiga Low Mileage Issue

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Originally Posted by guruji View Post
My ertiga has crossed 1L km recently and i am observing a drop in mileage these days. The running pattern also has changed....Can any one please help?
Would love if you could clarify the fuel and type and transmission. Those numbers look okay for a petrol MT or AT. They are marginally low for a diesel.
I’d check:
1. Clutch/Flywheel (if the car has a stick shift)
2. Fuel lines/pumps/injectors
3. Tire pressure (Tire health also)
4. Chauffeurs maybe abusing the clutch by driving in the second gear in crawling traffic
5. Air filter
6. Engine coolant levels
7. Check FE be taking it on a short highway sprint while maintaining a constant speed and measuring FE by tank-to-tank
8. Fill from reputed fuel stations
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Old 30th January 2020, 16:49   #738
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Default How to get best fuel efficiency - by accelerating quickly or slowly?

I was stumbling upon Quora and suddenly this question,

"What burns more gas, accelerating as fast as possible to 60 mph (e.g. 10 seconds) or accelerating slowly (e.g. 30 seconds)?"

caught my attention. I am in the impression that linear acceleration is best to get the maximum fuel efficiency. But to my surprise, if you check out the link and answers there, people are in favor of quick acceleration. This is fairly convincing and extremely debatable.

An excerpt from the comments there:
the quicker you get up to speed the less gas it takes to get there. That's all you have to think about, the longer you take to get up to speed the more gas it takes to do so and that is the whole story to it
It'd really interesting to know what fellow BHP-ians have to say about it.
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Old 30th January 2020, 16:57   #739
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Default Re: How to get best fuel efficiency - by accelerating quickly or slowly?

Both are wrong, accelerating slowly or rapidly.

There is an old classic thread on the topic here (ARTICLE: How to get the maximum Fuel Efficiency), I guess not much to add, just got to be in right gear so that engine is running close to optimum rpm.

Last edited by Thermodynamics : 30th January 2020 at 17:19.
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Old 30th January 2020, 17:58   #740
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Default Re: How to get best fuel efficiency - by accelerating quickly or slowly?

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Both are wrong, accelerating slowly or rapidly.

There is an old classic thread on the topic here (ARTICLE: How to get the maximum Fuel Efficiency), I guess not much to add, just got to be in right gear so that engine is running close to optimum rpm.
I absolutely agree with the points mentioned in the article. (Been a follower of TBHP for a long time).

On contrary to what's written in the answers on Quora, quick acceleration in cities will also result in more frequent deacceleration. Consequently squandering a lot of fuel.

I was intrigued with the answers there. That's why I thought to start a thread.
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Old 30th January 2020, 19:29   #741
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Default Re: How to get best fuel efficiency - by accelerating quickly or slowly?

The Quora article is very different from the TeamBHP thread, I believe.

The latter provides a lot of guidelines on how to drive as fuel efficient as possible.

The Quora article is just a simple debate and subsequent test on how to get up to a speed of 60 km/h in the most efficient way.

So that is a one off, nothing to do with real life driving, let alone driving in busy rural environment.

The point being made is that there is trade off due to time taken to reach that speed. The premises being to accelerate fast, because you get up to 60 mph quickly.

I haven't given it a huge amount of thought, but there is probably some element of truth in there.

To think this through, lets think about the two extremes; Very slow accelerating and very fast aggressive accelerating.

If you accelerate very slowly, it could actually take hours to get up to that speed of 60 km/h. Admittedly, the engine is producing very little power all that time, but it still using fuel for a very long time.

If you accelerate very aggressively, obviously you will get up to 60 mph very quickly. But red lining an engine itself will take a lot of fuel. But only for lets say 10 seconds.

So we have a slow case where we burn a tiny bit of fuel every second, for several hours.

And another case where we burn a lot of fuel per second in only 10 seconds

Gut feeling suggest that the latter one is still more fuel efficient. The most optimum is probably somewhere in between. It is balancing amount of power against time.

Engines run at different efficiencies across their power band. So you need to find a sweet spot, or rather range in the power band that gives the best performance (least absolute fuel burn) to reach 60 mph. It will most likely be different for different cars/engine/transmission, diesel versus petrol etc.

Jeroen
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Old 3rd February 2020, 20:53   #742
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Default Re: ARTICLE: How to get the maximum Fuel Efficiency

^^^
Wide open throttle (reduces pumping losses), but engine turning over slowly (specific fuel consumption figures can pinpoint figures), short shift, or use a cvt! Acceleration will not be brisk, but because of gearing, not throttle position.

Regards
Sutripta
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Old 3rd February 2020, 21:38   #743
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Default Re: Ertiga Low Mileage Issue

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Originally Posted by landcruiser123 View Post
Would love if you could clarify the fuel and type and transmission. Those numbers look okay for a petrol MT or AT. They are marginally low for a diesel.
It's petrol, manual. Thanks for the check points.. I am also now suspecting air filter and spark plugs. Will get them checked first. We recently changed the clutch suspecting that as the issue.
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