Petrol prices, and driveing sloooooow

[ozwinner]

Hi dudes.

I have noticed with the increase of fuel prices that ppl are driveing slower.

Does driveing slower actually save you money.

I figure. ( but I am a dill )

Weight of vehicle X distance travelled X rpm X time = fuel used.

So if you go slower it takes longer to use the same fuel for the journey.
But your fuel cost for the journey is the same.

If you travel faster ( Im talking of 100 kms ) you get there useing the same ammount of fuel as someone traveing at 70 kms, but faster.

I know there would be wind resistences etc.

But all these ppl travelling at 70 kms, are they saveing fuel??

Al :confused:

[DavidG]

Yes.
Air resistance is a square law.
Double the speed, four times the energy required to overcome the air.
Dropping the speed does improve fuel economy.
Try riding a motor bike to check out the air resistance.

[Gra]

I cant claim any real knowledge just some research and personal experience, having lived around cars fanatics all my life. You wont save much fuel by travelling slower in most cars, the only time being slower really can save you fuel is in the take off. The only real way to save fuel is to keep a constant speed at all times. Let the car do the slowing for you. On take off gently, gently until you are up to speed. so these 5 changes of speed limit in 5 K's really screws with that.

Thats my 2c anyway.

[Ianab]

You are probably thinking right Al

Each car will have a 'most efficient' speed.
What that is depends on the engine design, gearing, body aerodynamics etc.
The speed is probably somewhere between 70 and 110 ks, but to work it out you need a trip computer. 2 cars I've driven that had one were an Audi 100, and that showed least fuel used at 110 kph :eek: The other was an old 1300cc Mitsi mirage, and even that got best economy at ~100kph. (and 70kph was about the same as 115kph)

So I guess they say your mileage may vary :confused:

Cheers

Ian

[MathewA]

With highway driving I've found I get around 150kms per litre if I drive at 90kph instead of 100kph or more.

[ozwinner]

With highway driving I've found I get around 150kms per litre if I drive at 90kph instead of 100kph or more.

Thats some lean vehicle you drive Matt.
I get 16l per 100 kms out of mine.

Al

[MathewA]

I think I need to re-write that. I get an extra 150km per fill up if I keep the speed at around 90kph than if I drive at 100kph. About 750km/42litres

[ozwinner]

MPG is far easier to work out isnt it?

Took me ages to figure out this metric rubbish.

Al

[Grunt]

Accelerating quickly also uses more petrol. How fast can you get to 60kph?

[ozwinner]

I know accelerating quickly uses more fuel, I assume all you old buggers drive smoothly and calmly.

No harse accelerating, braking. etc.

Al

[JDarvall]

Maybe, the day will come where petrol will become so expensive we'll be cutting holes under the pedals and just run our cars to and from work ,,, Fred Flinstone style.

Be good for the environment, wouldn't it ?

[ozwinner]

Maybe, the day will come where petrol will become so expensive we'll be cutting holes under the pedals and just run our cars to and from work ,,, Fred Flinstone style.

Be good for the environment, wouldn't it ?

Yabba dabbaa doooo!!!!!

Fred

[Cliff Rogers]

Just be happy that ya car doesn't run on ottled water or Coke.

[Gumby]

High petrol prices have increased the cost of lots of things delivered by road, Bread, milk, vegies, meat....I'm wondering if the price of petrol also increases the price of petrol. It's delivered by road too ?

[Grunt]

High petrol prices have increased the cost of lots of things delivered by road, Bread, milk, vegies, meat....I'm wondering if the price of petrol also increases the price of petrol. It's delivered by road too ?

Quite so, Gumby. It's a vicious cycle. The price of petrol increases the cost of delivering petrol which in turn increases the price of petrol which in turn …

Expect the price to be $10 per litre next week