Thread: Fuel consumption

Originally Posted by rangy01

If both vehicles are manual, and you use the same gear, then both engines will have done the same total revolutions.
(subject to any wheel slip etc)
Therefor one wil have the throttle open further to maintain the higher speed so must use more fuel (all things being equal such as wind, day temperature etc).

How did you come to this answer?

Originally Posted by Traveler

How did you come to this answer?

with great ease, the faster vehicle has greater drag, due to pushing throught the air at a greater rate of knots, needing to apply more pedal, reducing engine vacuum, sucking more fuel

If you want economy, buy a vacuum gaufe, but it'll only teach you not to open the throttle and not labour the engine, lesser revs doesn't always better economy

Your maths are incorrect.
The difference between 2000RPM and 1750 RPM is 1.1428571.
Your time difference between 10 minutes and 7 is 1.4285714.
So the times should be 7 minutes and 7.9999997 minutes.
so total Revolutions of the motor are
1750x7.9999997= 13999.999
2000x7= 14000
This is only logical since the distance is the same.
Regards Philip A

Mate, I couldn't give a rat's bum about all this mathematical mumbo jumbo. I'm only interested in the bloody truck starting and getting me to where I want to and back again without a break down. I thought it was common knowledge that the faster you go, the more fuel you use. The slower, the less fuel. This is irrespective if you're driving a European V12 or 1 litre Japanese soap box.

I can't remember where.... maybe a 4x4 mag but they did a test similar to this idea to work out the "best" economy speed. I'm going from memory but... (and using a few differnt types of 4x4 to get an "average"

80 was the most "economical" (for the test dropping the speed lower did not make much of a difference to consumption so was deemed the best speed)

They went in to the maths on it but due to drag etc etc the power required to increase the speed above this takes a steep climb and obviously this means more fuel use. From memory 80-90 wasn't a huge difference but wasn't as economical 90-100 the consumption climbed steeper on the graph and 100-110 it got scary.

Sorry I can't remember the figures. The power required to increase the speed by 10km/h as you got faster was requiring a lot more power than the previous bracket

Sounds like we need mythbusters on this one .

Originally Posted by 001525

Mate, I couldn't give a rat's bum about all this mathematical mumbo jumbo. I'm only interested in the bloody truck starting and getting me to where I want to and back again without a break down. I thought it was common knowledge that the faster you go, the more fuel you use. The slower, the less fuel. This is irrespective if you're driving a European V12 or 1 litre Japanese soap box.

their is always one...

Originally Posted by Traveler

their is always one...

So what's the point in this exercise??