Fuel Economy

[zamtresco]

I went to Singapore from Kemaman recently for buss trip. On our way back to Kemaman, I top up to full tank at JB. The scenario is like below. Driver A He drove from Shell Petrol Station at Stulang to Machap. Approx around 70 kms. Average speed was 150km/h Driver B (myself)1) Frm machap r&r to yong peng exit.Approx 30 kms.Avg speed was 200 km/h 2) Frm Yong Peng (U) exit to Segamat town. Approx 100 kms. Avg speed 100 kmh 3) From Segamat to Muadzam Shah, Approx 70 kms. Avg speed 170 km/h Driver CFrom Muadzam to Kemaman, Approx 150 kms. Average speed - no idea. slept all the way to kemaman. What surprised me was, when I arrived kemaman, the trip meter clocked 420 kms but the fuel meter is only at half tank! Normally, although am using highway like Lebuhraya Pantai TImur, no matter how gentle i am with the accelarator pedal, the most i can get is 360 +/- kms for half tank.This is like average speed of 100 km/h all the way to KL from Kemaman. But this time, although using old trunk road, but yet I still can get 420 kms for half tank. Mind that I am using Shell petrol all these while and never change to any brand. So it cant be the petrol. No recent service done to my car before the trip. So definitely not bcos of new engine oil. Or is it outside temp that have contributing factor to fuel economy. It was raining heavily that evening and I took off from JB around 10 PM and arrive Kemaman around 3:30 am. So my question now, what else can be the contributing factor to fuel economy?

 

[jarance]

did you forget to mentione that there was a fat lady sitting behind?? lol

 

[rookie]

Lower temp would definitely have an effect since lower temp air will have more O2 compared to higher temp air, which means more uhmmppphh. Other factors could be traffic, number of lorries to overtake, etc

 

[535i]

1) Low external temp
2) New lighter paint
3) Less 'xtra baggage'

 

[anaksarawak]

I went to Singapore from Kemaman recently for buss trip. On our way back to Kemaman, I top up to full tank at JB. The scenario is like below.

Driver A

He drove from Shell Petrol Station at Stulang to Machap. Approx around 70 kms. Average speed was 150km/h

Driver B (myself)

1) Frm machap r&r to yong peng exit.Approx 30 kms.Avg speed was 200 km/h

2) Frm Yong Peng (U) exit to Segamat town. Approx 100 kms. Avg speed 100 kmh

3) From Segamat to Muadzam Shah, Approx 70 kms. Avg speed 170 km/h

Driver C

From Muadzam to Kemaman, Approx 150 kms. Average speed - no idea. slept all the way to kemaman.

What surprised me was, when I arrived kemaman, the trip meter clocked 420 kms but the fuel meter is only at half tank!

Normally, although am using highway like Lebuhraya Pantai TImur, no matter how gentle i am with the accelarator pedal, the most i can get is 360 +/- kms for half tank.This is like average speed of 100 km/h all the way to KL from Kemaman.

But this time, although using old trunk road, but yet I still can get 420 kms for half tank.

Mind that I am using Shell petrol all these while and never change to any brand. So it cant be the petrol. No recent service done to my car before the trip. So definitely not bcos of new engine oil.

Or is it outside temp that have contributing factor to fuel economy. It was raining heavily that evening and I took off from JB around 10 PM and arrive Kemaman around 3:30 am.

So my question now, what else can be the contributing factor to fuel economy?

I always believe cooler air will help the engine to run better..

Some say, driving slow (80-100km/h) might not help in FC.. If our right foot is active.

My most recent experience of FC and shocked to find there a lot of diff between using cruise control and our right foot on northsouth higway.

From Sri Petaling to Johor Bharu - without cruise control RM58 or 331km but for return with Cruise Control on for 80% of the time RM43 or 326KM

Average speed 120-160km on highway.

My cousin's ride is E46 320 year 2002, 16' rims and with 2 passengers (sunny hot day with aircon on)

Imight be wrong...but I hope this help... I am sure many other will help you too.



Cheers

 

[M30]

i belive it is the lower out side temp, coz with the lower external temp not only would you have more power from the engine but the air condition compressor kicks in less time and run shorter compare to a afternoon drive or a normal night drive from what i notice on my E23.

 

[Zoggee]

I believe your petrol gauge wiring is fautly.

 

[syahruln]

Best way to measure is to fill it up before your trip and reset your odometer. When you have reached your destination, fill it up again to see how much petrol you've used and check the odometer to see how far you have travelled with that amount of money/petrol. I definitely have to do it this way coz my petrol gauge is only accurate when it's full or when it's empty

 

[doink]

as far as i know...if u travel more on highway with constant speed...higher cc engine tends to drink much more less fuel compared to lower cc engines...the power required to move the car at constant speed is very low...plus bigger engine has more torque at low rpm...

 

[Lee36328]

Here are some contributing factors to fuel economy that i can remember.

1. quality of fuel
2. efficiency of engine
3. air intake, intake manifold, etc - no leaks
4. exractors/headers, exhaust, etc - no leaks, no blockage
5. 02 sensors, intake temperatur sensors, all sensors in general - in good shape
6. tires, treads, balancing, and alignment (zero toe is best for fc)
7. temperature of the air, which affects air density
8. elevation above sea level, air density again
9. load on the engine - air cond, bagage, passenger, YOU, overall weight
10. gearbox - in good shape?
11. drive shaft - everything as tight as it should be?
12. spark plugs
13. engine oil - lighter oil is better for fc but maybe less protection, esp for older engines
14. fuel mapping - how you have been driving for the last x (forgot how many) kms
15. any other mods or add-ons which may help or hinder fc
16. speed of driving - there is an optimum rpm and speed for fc
17. style of driving - smooth or sudden surge/stops

FC is a reflection of efficiency.
1. usage - drive at the most efficient power band of the engine as much as possible.
2. condition - maintain every aspect of the car to keep it in good condition
3. fuel and air - good quality fuel and cool dense air
4. load - minimize load as much as you can

 

[ALBundy]

Here are some contributing factors to fuel economy that i can remember.

1. quality of fuel
2. efficiency of engine
3. air intake, intake manifold, etc - no leaks
4. exractors/headers, exhaust, etc - no leaks, no blockage
5. 02 sensors, intake temperatur sensors, all sensors in general - in good shape
6. tires, treads, balancing, and alignment (zero toe is best for fc)
7. temperature of the air, which affects air density
8. elevation above sea level, air density again
9. load on the engine - air cond, bagage, passenger, YOU, overall weight
10. gearbox - in good shape?
11. drive shaft - everything as tight as it should be?
12. spark plugs
13. engine oil - lighter oil is better for fc but maybe less protection, esp for older engines
14. fuel mapping - how you have been driving for the last x (forgot how many) kms
15. any other mods or add-ons which may help or hinder fc
16. speed of driving - there is an optimum rpm and speed for fc
17. style of driving - smooth or sudden surge/stops

FC is a reflection of efficiency.
1. usage - drive at the most efficient power band of the engine as much as possible.
2. condition - maintain every aspect of the car to keep it in good condition
3. fuel and air - good quality fuel and cool dense air
4. load - minimize load as much as you can

Mr. Lee ah, voltage stabiliser can help FC anot? I want to fix 4 in my car, since its a four pot

 

[JoeYazid]

Zam,

That comparison cannot be use for you because you are flying not driving further more yr car gor 2 power stabalizer. hahahahaha

 

[sesat88]

if u campur the angpows from the michael jacksons, ya won't be getting any good FC anyhow... especially on highway travel.

 

[rubes72]

hey zam, the cooler air doesn't only give you better fuel economy, but when outside temp is low, the fuel tank retains more fuel. when temp is high, the fuel in your tank changes to vapor and is vented out. it also helps when you fuel up, that the ambient temp is not extreme. you lose a few mils there,and when you do fuel up, try not to pull the pump trigger fully. halfway gives you more fuel. the explanation is that though the delivery of fuel is the same, but with high pressure fueling causes molecular vibrations, which translates to vapor. plus the pumps measures delivery at 23ms and is verified by 3 sensors, therefore if fueling is faster than 23ms per ml, then you might lose a few mili-litres.

 

[E46Fanatic]

Although colder and denser air will give you better power, I would think that you'll burn more fuel. Air/fuel mixture is controlled by the ECU, more air = more fuel as well? I distinctly remember that my FC of my car sux big time during winter in the US vs. summer. Anyone can concur their experience with me?

Then again, when its very hot, usually the A/C works harder using more energy, and if its too hot the ECU richens the fuel mixture to keep the engine cool.

Also when its raining heavilly, there is much more rolling resistance of the tyre splashing its way through standing water. Bad news for FC.

 

[flash]

You did mention you were asleep... are you sure your driver did not stop halfway before Kemaman to top up????

 

[zamtresco]

Hahahahaha... definitely not... if not he was, for sure will wake me up to pay the petrol!!! hahahahaha

 

[mohdrozali]

You are lucky. Did what Syahruln advice but concluded that my 5-series is doing less than 8km/liter travelling at average speed of 140km/ph. Any suggestion on what I should do?

 

[Lee36328]

You are lucky. Did what Syahruln advice but concluded that my 5-series is doing less than 8km/liter travelling at average speed of 140km/ph. Any suggestion on what I should do?

Hard to say for sure what the problem is without more information, but a general approach which makes sense to me is this.

Try to restore the car to its optimum running condition in order to get closed to optimum efficiency.

As our cars age, the initial efficiency degrades with time and wear and tear. So, regular maintenance to reduce the wear and tear would help. So would replacement of any worn parts, anything from the engine all the way to the tires via the driveline.

Also, remove any excess weight from the car. How empty is your boot? :wink:

What is the mileage of your car. Any rebuild done to the engine? Time to rebuild?

How is the condition of your gearbox?

Etc, etc.

 

[Lee36328]

Although colder and denser air will give you better power, I would think that you'll burn more fuel. Air/fuel mixture is controlled by the ECU, more air = more fuel as well? I distinctly remember that my FC of my car sux big time during winter in the US vs. summer. Anyone can concur their experience with me?

Then again, when its very hot, usually the A/C works harder using more energy, and if its too hot the ECU richens the fuel mixture to keep the engine cool.

Also when its raining heavilly, there is much more rolling resistance of the tyre splashing its way through standing water. Bad news for FC.

Cooler air, denser, more O2, more efficient combustion. Up to a certain range, not winter temperature (you're right about winter), which is too cold for efficient combustion.