ARTICLE: How to get the maximum Fuel Efficiency

gpa · 3rd July 2009, 14:43

Quote:

Originally Posted by Roy.S

Well, I intend to drive with a heavy foot until the fuel prices go up.

With petrol prices up by Rs. 4 per litre, guess, its back to sedate driving now, eh?

coolboy007 · 3rd July 2009, 17:12

This is what am doing with my LINEA as an experiment for 2-3 weeks to see max mileage and the result is my car in delhi traffic (Linea 1.4 petrol) has delivered max FE till now of 12.20 in city with AC on. I find it too good as some 1.2 i10 owners get less FE than me

1. Have reduced my gearshifts RPM limit from 3000 to 2500, i know its very tough for me to hold but just a matter of few weeks to see how much i can reduce fuel consumption.

2. As soon as cabin gets cool i switch off the ACC (24 degress) using compressore button (only in evenings and not afternoon with 45 degrees) , i know its stupid as ACC is there not to be fiddled with but am ok with a little less cool air for 1 min and it gives me immense joy when i get 12 + fe in a petrol Linea.

3. Not doing sudden gear changes to 2nd from 3rd to get that intiitial pickup from the car. My car never knocks even if i touch 25-30 km/h in 5th gear.

So 3000 kms will be completed, car will be run in nicely and after that i will again start flooring accelerator. With 4 re hike i must use above 3 steps to reduce fuel bills.
All 3 steps looked silly to me but when FE increased from 10.5-11 to 12.2 i say heck who cares.

janitha · 3rd July 2009, 18:19

Quote:

Originally Posted by arjyamaj

So you really dont have to have a maximum idle time of 2 minutes. My guess is that 10-15 secs should be enough to turn off your engine and restart again.

What if the vehicle has a turbo engine and the driver is to switch off for 10-15 seconds at the red light. He has to idle for one minute before switching off and after starting! What will be his fate?

arjyamaj · 4th July 2009, 11:07

Quote:

Originally Posted by janitha

What if the vehicle has a turbo engine and the driver is to switch off for 10-15 seconds at the red light. He has to idle for one minute before switching off and after starting! What will be his fate?

Ah well, diesel is cheaper than petrol isnt it?

And isnt it an established rule that what you gain in performance, you lose in efficiency?

gpa · 4th July 2009, 11:57

Quote:

Originally Posted by coolboy007

My car never knocks even if i touch 25-30 km/h in 5th gear.

coolboy007,

This is not a good way to increase your FE. Lugging your engine (5'th gear at 25-30 kmph), puts immense amounts of strain on your engine and driveshaft. What you save in terms of fuel, you will loose in terms of damage to your engine.

A simple way to understand the stresses on your engine, would be to start pedalling a bicycle in a high gear on a flat road or gradient. You will have to use immense power of your muscles to get the bike moving than if you were to start pedalling on a low gear like gear 1.

Your car's manual will have recommended shift speeds mentioned and it is best you stick to that to achieve optimum FE.

Cheers,
gpa

coolboy007 · 4th July 2009, 13:43

Quote:

Originally Posted by gpa

coolboy007,

This is not a good way to increase your FE. Lugging your engine (5'th gear at 25-30 kmph), puts immense amounts of strain on your engine and driveshaft.

Thanks for your concern. I am sorry if i didnt explain properly, this was just a test to see how much can my car go in 5th gear without knocking and later came to know that its a robotised fire engine and it wont knock

If i go till 25 -30 in 5th gear and i press the accl pedal fully the car doesnt even budge, its a petrol Linea and have to make quick shifts to pick up.
If i move in 25-30 in 5th gear and then expect pick up from my car, it will take ages and delhi people will kill me.

Anyways, Linea's manual hasnt mentioned anything regarding Desired gear and relative speeds. Strange but true.
I use 5th gear as soon as i hit 45-50 when am in a sedate driving mood, my car doesnt complaint and i hope i am not killing my engine if i use 5th at 45-50 km/h.

janitha · 4th July 2009, 13:55

Quote:

Originally Posted by arjyamaj

Ah well, diesel is cheaper than petrol isnt it?

And isnt it an established rule that what you gain in performance, you lose in efficiency?

What I wanted to highlight was the need to idle for one minute after starting and before switching off, that too at a signal where vehicles are waiting in front of and behind you.

gpa · 4th July 2009, 21:55

Quote:

Originally Posted by coolboy007

Anyways, Linea's manual hasnt mentioned anything regarding Desired gear and relative speeds. Strange but true.
I use 5th gear as soon as i hit 45-50 when am in a sedate driving mood, my car doesnt complaint and i hope i am not killing my engine if i use 5th at 45-50 km/h.

coolboy007,

It is very strange indeed that your manual doesn't mention shift speeds/rpms. Shifting to 5'th gear at 45-50 kmph is fine and will have no adverse affects on your engine.

Cheers,
gpa

Roy.S · 4th July 2009, 23:54

Quote:

Originally Posted by gpa

With petrol prices up by Rs. 4 per litre, guess, its back to sedate driving now, eh?

Actually I figured that ever since quit smoking, I'm saving about Rs. 2k a month anyway, so it continues to be pedal to metal!

gpa · 5th July 2009, 20:20

Quote:

Originally Posted by Roy.S

Actually I figured that ever since quit smoking, I'm saving about Rs. 2k a month anyway, so it continues to be pedal to metal!

This is just brilliant!

msetlur · 14th July 2009, 22:37

There is some "play" with my clutch pedal (I don't know how else to word that) and I have the habit of keeping my foot on the pedal even when not changing gears. I was under the impression that this does not actually cause the clutch to 'engage'.

Please do let me know if I am wrong. I find it a little to take the foot off and put it back on the clutch in the heavy bumper to bumper traffic in B'lore, but I will change my driving style if it is in the interest of FE

ImmortalZ · 15th July 2009, 01:33

You need to change your driving style for the sake of your clutch before FE. Placing your foot on the clutch while driving will cause the clutch to start slipping and cause premature wear and low FE.

msetlur · 15th July 2009, 07:47

Thank you ImmortalZ. I will ensure that my foot is not parked on the clutch unless I am changing gears.

9216 · 25th July 2009, 23:54

Hello all,

I agree that a lot have been discussed about fuel efficiency. I would, however, like Gurus in this forum to clarify this:

(1) Is there an accurate method to measure fuel consumption in ordinary cars (I mean relatively inexpensive cars) other than fill-to-fill. ("fill" varies from fill to fill, because of air space in tanks).

In old carb days, it was easy to attach a tube to fuel pump inlet and run from a bottle of measured quantity of fuel ( for an occasional test, at least).

(2) Will there be any adverse effects in running the car till tank is empty and engine stops? I mean, is "empty to empty" a more accurate method? (accepting the associated inconveniences, of course)

Thanks for any possible inputs.

Prasad.

Takumi-san · 26th July 2009, 06:50

Empty to Empty is not a more accurate method. Besides I am quite sure that its not good news for your fuel pump which is desperately trying to pump vapours.

The fill will not vary because you are supposed to use the auto-cutoff on the pump. This will remain the same (at the same pump, same temperature etc). Try to fill up again on the same day or the next and in similar weather. Speaking of which, there is an interesting thread here which claims that temperature may be responsible for differing fuel efficiency , in which case your experiment may need to be repeated every few months for a year

3rd July 2009, 17:12	#317
coolboy007 Senior - BHPian Join Date: Mar 2009 Location: New Delhi Posts: 1,852 Thanked: 2,137 Times	This is what am doing with my LINEA as an experiment for 2-3 weeks to see max mileage and the result is my car in delhi traffic (Linea 1.4 petrol) has delivered max FE till now of 12.20 in city with AC on. I find it too good as some 1.2 i10 owners get less FE than me 1. Have reduced my gearshifts RPM limit from 3000 to 2500, i know its very tough for me to hold but just a matter of few weeks to see how much i can reduce fuel consumption. 2. As soon as cabin gets cool i switch off the ACC (24 degress) using compressore button (only in evenings and not afternoon with 45 degrees) , i know its stupid as ACC is there not to be fiddled with but am ok with a little less cool air for 1 min and it gives me immense joy when i get 12 + fe in a petrol Linea. 3. Not doing sudden gear changes to 2nd from 3rd to get that intiitial pickup from the car. My car never knocks even if i touch 25-30 km/h in 5th gear. So 3000 kms will be completed, car will be run in nicely and after that i will again start flooring accelerator. With 4 re hike i must use above 3 steps to reduce fuel bills. All 3 steps looked silly to me but when FE increased from 10.5-11 to 12.2 i say heck who cares.
	() Thanks

14th July 2009, 22:37	#326
msetlur BHPian Join Date: Jul 2009 Location: Bangalore Posts: 37 Thanked: 2 Times	There is some "play" with my clutch pedal (I don't know how else to word that) and I have the habit of keeping my foot on the pedal even when not changing gears. I was under the impression that this does not actually cause the clutch to 'engage'. Please do let me know if I am wrong. I find it a little to take the foot off and put it back on the clutch in the heavy bumper to bumper traffic in B'lore, but I will change my driving style if it is in the interest of FE
	() Thanks

15th July 2009, 01:33	#327
ImmortalZ Senior - BHPian Join Date: Jan 2008 Location: Trivandrum Posts: 2,179 Thanked: 488 Times View My Garage	You need to change your driving style for the sake of your clutch before FE. Placing your foot on the clutch while driving will cause the clutch to start slipping and cause premature wear and low FE.
	() Thanks

15th July 2009, 07:47	#328
msetlur BHPian Join Date: Jul 2009 Location: Bangalore Posts: 37 Thanked: 2 Times	Thank you ImmortalZ. I will ensure that my foot is not parked on the clutch unless I am changing gears.
	() Thanks

25th July 2009, 23:54	#329
9216 BHPian Join Date: Mar 2009 Location: Palakkad Posts: 61 Thanked: 170 Times	About FE once again Hello all, I agree that a lot have been discussed about fuel efficiency. I would, however, like Gurus in this forum to clarify this: (1) Is there an accurate method to measure fuel consumption in ordinary cars (I mean relatively inexpensive cars) other than fill-to-fill. ("fill" varies from fill to fill, because of air space in tanks). In old carb days, it was easy to attach a tube to fuel pump inlet and run from a bottle of measured quantity of fuel ( for an occasional test, at least). (2) Will there be any adverse effects in running the car till tank is empty and engine stops? I mean, is "empty to empty" a more accurate method? (accepting the associated inconveniences, of course) Thanks for any possible inputs. Prasad.
	() Thanks

26th July 2009, 06:50	#330
Takumi-san BHPian Join Date: Apr 2009 Location: Melbourne Posts: 368 Thanked: 121 Times View My Garage	Empty to Empty is not a more accurate method. Besides I am quite sure that its not good news for your fuel pump which is desperately trying to pump vapours. The fill will not vary because you are supposed to use the auto-cutoff on the pump. This will remain the same (at the same pump, same temperature etc). Try to fill up again on the same day or the next and in similar weather. Speaking of which, there is an interesting thread here which claims that temperature may be responsible for differing fuel efficiency , in which case your experiment may need to be repeated every few months for a year
	() Thanks