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Old 23rd April 2011, 00:23   #496
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Default Re: ARTICLE: How to get the maximum Fuel Efficiency

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Originally Posted by rlakhanpal View Post
I do have a question on it though - given the claimed benefits of engine maintenance through the use of these premium fuels, does it help to use these once every 3-4 fills or should one rather use additives during each service?
The only benefit to engines from Premium fuels in cars with compression ratio that is below 9.4 or 9.6 is cleansing of the injector nozzles. This claim is also suspect. It would be worth your while if you used specialty additives instead.

Super plugs and super fuels in normal engines are just a hype with negatives impact on power and fuel efficiency.
Please read up on making of a fat spark and also on the inherent energy in premium fuels compared to normal 87 octane petrol.

I ain't talking of super diesels here as they are a strict no no for all main injection pumps of CRDI engines.
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Old 23rd April 2011, 08:39   #497
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Default Re: ARTICLE: How to get the maximum Fuel Efficiency

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Originally Posted by kgkaran View Post
Do the extra octane fuels like Xtra Premium and Xtra Mile have any real impact on fuel efficiency? Especially given the price difference... for example Xtra Mile comes for a 15% price hike, so does it give a 15% better mileage?
I have no idea about diesel fuel brands, but all the premium petrols are of the same octane as regular petrol - 91 RON. Xtra Premium from IOC, Power from HP, Speed from BP and Shell Super belong to this category. The difference is they contain some additives to keep the engine/injectors clean.

The lone exception is Speed 97 from BP, which is the ONLY high octane (97 RON) petrol available in India to my knowledge.

Last edited by Gansan : 23rd April 2011 at 08:42.
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Old 23rd April 2011, 15:30   #498
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Default Re: ARTICLE: How to get the maximum Fuel Efficiency

My two paisa on improving FE - http://www.team-bhp.com/forum/test-d...ml#post2314158 (Medium Grey Tank - New Palio Stile 1.3 MJD)

This should be helpful particularly to 1.3 MJD owners (vista diesel, linea 1.3, manza 1.3, swift diesel, palio stile 1.3 MJD)
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Old 5th May 2011, 00:30   #499
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Default Re: ARTICLE: How to get the maximum Fuel Efficiency

My Beat was initially chauffeur driven all through the run-in period. The car was rashly driven at RPMs well above 2.5 and 3k even. No matter how sanely I drive the car now, I hardly get around 12.1/12.2 kmpl. which is bad. I am planning to due an ECU re-amp on the next service, which will improve the FE and also provide an increased torque output.
Could experts suggest some other ways to improve the FE?
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Old 5th May 2011, 09:41   #500
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Default Re: ARTICLE: How to get the maximum Fuel Efficiency

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Originally Posted by Skye1592 View Post
My Beat was initially chauffeur driven all through the run-in period. The car was rashly driven at RPMs well above 2.5 and 3k even. No matter how sanely I drive the car now, I hardly get around 12.1/12.2 kmpl. which is bad. I am planning to due an ECU re-amp on the next service, which will improve the FE and also provide an increased torque output.
Could experts suggest some other ways to improve the FE?
How much do you think you should be getting?

Also, you should be driving at least above 2k rpm and gear change should happen closer to 3k rpm.

How old is the car btw? Have a good service record, keep the tyre pressure correct; guess that should give you optimum FE.
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Old 5th May 2011, 09:58   #501
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Default Re: ARTICLE: How to get the maximum Fuel Efficiency

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Originally Posted by libranof1987 View Post
How much do you think you should be getting?

Also, you should be driving at least above 2k rpm and gear change should happen closer to 3k rpm.

How old is the car btw? Have a good service record, keep the tyre pressure correct; guess that should give you optimum FE.
I think I should be getting around 15 kmpl in the city. The car is an year old. It was BADLY driven for the first 5,000 kms or so. I maintain the recommended 32 psi in all tires.
I thought the optimum RPM to do the gear change is at 1.5 to 2k? I always up-shift before the RPM meter hits 2.5 k.

Thanks!
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Old 5th May 2011, 10:07   #502
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Default Re: ARTICLE: How to get the maximum Fuel Efficiency

I am sorry, but my Car gives terrible FE inside city confines.

Out on the highway, the FE hovers around ~20 something despite the revs being kept around 3K. (the fuel needle doesn't budge)

I haven't calculated my city & highway FE separately, but its 16kpl thereabouts (combined) since I bought the Car.

The climate control always works and tire pressure is ideally maintained. I try not to lug & minimize the use of clutch.

Is 16kpl a good FE in a combined circle with 100% a/c?
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Old 5th May 2011, 10:10   #503
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Default Re: ARTICLE: How to get the maximum Fuel Efficiency

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Originally Posted by Skye1592 View Post
I think I should be getting around 15 kmpl in the city.
Thanks!
That is the kind of mileage the M800 and Alto 800 may return, not the Beat. I think your mileage is OK.
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Old 5th May 2011, 10:16   #504
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Default Re: ARTICLE: How to get the maximum Fuel Efficiency

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Originally Posted by Sheel View Post
I am sorry, but my Car gives terrible FE inside city confines.

Out on the highway, the FE hovers around ~20 something despite the revs being kept around 3K. (the fuel needle doesn't budge)

I haven't calculated my city & highway FE separately, but its 16kpl thereabouts (combined) since I bought the Car.

The climate control always works and tire pressure is ideally maintained. I try not to lug & minimize the use of clutch.

Is 16kpl a good FE in a combined circle with 100% a/c?
Again, which car is this? But 16kmpl with 100% a/c sounds really good!

You cannot expect more than 15-16kmpl in the city with 100% a/c because of the amount of idling time, traffic jams and start-stop situations.

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Originally Posted by Skye1592 View Post
I think I should be getting around 15 kmpl in the city. The car is an year old. It was BADLY driven for the first 5,000 kms or so. I maintain the recommended 32 psi in all tires.
I thought the optimum RPM to do the gear change is at 1.5 to 2k? I always up-shift before the RPM meter hits 2.5 k.

Thanks!
No; if you're upshifting before 1 to 2k, you're depriving the engine of some fuel. Eventually, there'll be engine-knocking and you're FE will drop further.

Try driving with upshifts between 2.5-3k; FE should improve.
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Old 5th May 2011, 10:21   #505
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Default Re: ARTICLE: How to get the maximum Fuel Efficiency

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Originally Posted by libranof1987 View Post
Again, which car is this? But 16kmpl with 100% a/c sounds really good!

You cannot expect more than 15-16kmpl in the city with 100% a/c because of the amount of idling time, traffic jams and start-stop situations.
Ford Figo TDCi

Seems I need not worry. Though I don't really commute inside city and of the 4,500 kms the Car has done, not even 500 would have been inside city confines.
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Old 5th May 2011, 10:26   #506
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Default Re: ARTICLE: How to get the maximum Fuel Efficiency

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Originally Posted by Gansan View Post
That is the kind of mileage the M800 and Alto 800 may return, not the Beat. I think your mileage is OK.
I have contacts with two other friends who own the beat, and they get around 15.4 to 16 kmpl within the city and 18 in the highway. Whereas I get only around 14 kmpl on the highway. You understand my skepticism.

Thanks!

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Originally Posted by libranof1987 View Post
No; if you're upshifting before 1 to 2k, you're depriving the engine of some fuel. Eventually, there'll be engine-knocking and you're FE will drop further.

Try driving with upshifts between 2.5-3k; FE should improve.
Didn't experience engine knock till now. Thanks, will try that!
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Old 5th May 2011, 11:19   #507
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Default Re: ARTICLE: How to get the maximum Fuel Efficiency

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Originally Posted by libranof1987 View Post

No; if you're upshifting before 1 to 2k, you're depriving the engine of some fuel. Eventually, there'll be engine-knocking and you're FE will drop further.

Try driving with upshifts between 2.5-3k; FE should improve.
I always thought upshifting was to be done at 2k rpm. Is this thumb rule valid for all all cars? I mean for hatchbacks as well as sedans? In order to get better FE I constantly look at the rpm meter so that I can change gears perfectly. This makes driving less fun. SOmetimes I think whether its worth being so much careful with gear changes. I shall rather work hard and earn a little more ( or spend somewhere else less) to put more fuel. I will certainly try the change gears at 2.5k rpm now. What is engine knocking?
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Old 5th May 2011, 11:35   #508
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Default Re: ARTICLE: How to get the maximum Fuel Efficiency

You never feel the knock due to the knock sensor. When the sensor detects the know to compensate the knocking it will increase the fuel. Hence in mpfi engines if you lug the engine by switching to high gears it will NOT give mileage. If you have driven two wheeler you can easily identify knock. Its like pinging in the cylinders kat-kat noise results in improper fuel burning and vibrations.
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Old 5th May 2011, 12:23   #509
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Default Re: ARTICLE: How to get the maximum Fuel Efficiency

^
I do have a theoretical knowledge of engine knocking. I don't know how I would detect one though. I've driven two wheelers and not experienced knocking. What you are saying is the sensor counter-acts the knocks? And so we don't have to bother about knocking ever occurring?
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Old 5th May 2011, 13:08   #510
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Default Re: ARTICLE: How to get the maximum Fuel Efficiency

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Originally Posted by Saanil View Post
I always thought upshifting was to be done at 2k rpm. Is this thumb rule valid for all all cars? I mean for hatchbacks as well as sedans? In order to get better FE I constantly look at the rpm meter so that I can change gears perfectly. This makes driving less fun. SOmetimes I think whether its worth being so much careful with gear changes. I shall rather work hard and earn a little more ( or spend somewhere else less) to put more fuel. I will certainly try the change gears at 2.5k rpm now. What is engine knocking?
It is valid for all vehicles. Gear change should happen between 2.5k -3k rpm for optimum engine performance and FE. (of course, you can be on the 5th gear at 30 km/hr or 100 km/hr on the 3rd at the cost of the engine and FE).


Engine knocking is what you hear when the engine is in high gear and it is not getting enough fuel. You don't necessarily hear it all the time as the in current mpfi engines, the fuel flow is adjusted.

As vijay pointed out, try it on a 2-wheeler; switch to 4th at 20 km/hr, you will hear the engine whining "tak-tak" and if you don't "raise", it will eventually die.

Quote:
Originally Posted by Skye1592 View Post
^
I do have a theoretical knowledge of engine knocking. I don't know how I would detect one though. I've driven two wheelers and not experienced knocking. What you are saying is the sensor counter-acts the knocks? And so we don't have to bother about knocking ever occurring?
You have to! Upshift at proper rpm; else engine will suffer damage.
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