something to ask about fuel consumption..

• kohanson

  15 Jan 05, 17:53

  Let's say i am travelling at 80 km/h...
  
  if i am using 4th gear to travel at that speed, my rpm will be around 2.5k ..
  And if i am using 5th gear at that speed, my rpm will be around 2k..
  
  So, at which gear will i consume more petrol?
  Is it higher rpm = more petrol consumption?
  But if i am at about 60km/h and i engage 5th gear, i need to step on more on the accelerator to have abit more power.. So will this consume more petrol?
• bismarck

  15 Jan 05, 18:07

  Originally posted by kohanson:

  Let's say i am travelling at 80 km/h...
  
  if i am using 4th gear to travel at that speed, my rpm will be around 2.5k ..
  And if i am using 5th gear at that speed, my rpm will be around 2k..
  
  So, at which gear will i consume more petrol?
  Is it higher rpm = more petrol consumption?
  But if i am at about 60km/h and i engage 5th gear, i need to step on more on the accelerator to have abit more power.. So will this consume more petrol?

  i guess lower rpm less petrol used. because yr fuel feeds the rpms.
• nOrmalbOi

  15 Jan 05, 18:09

  Generally speaking.
  
  When the engines does more work it drinks more pretrol. When it is trying harder it drinks more petrol.
• sgboy2004

  15 Jan 05, 18:10

  rpm...wat happens if u go down slope har??
• kohanson

  15 Jan 05, 18:15

  Originally posted by sgboy2004:

  rpm...wat happens if u go down slope har??

  Good question, its using engine braking so maybe minimum petrol being feed in.. This thing until now i still don't understand..
• nOrmalbOi

  15 Jan 05, 18:17

  revs go up when u using engine braking.
  
  revs go up == more petrol burnt.
• wbucket

  15 Jan 05, 20:19

  Originally posted by kohanson:

  Good question, its using engine braking so maybe minimum petrol being feed in.. This thing until now i still don't understand..

  Isn't the fuel got feed proportional to the amount you step on the pedal? So since when down-slope, you don't push as hard, so fuel usage is lessen. However, down-slope should use more fuel than flat ground because the slope is pulling the car down, thus increases the speed and rpm, so the engine will draw more fuel.
  
  I think the reason why at 5th gear, it takes more fuel to accelerate is because of the gear ratio thing. Since it is harder, you push more, so more fuel. If you don't know why harder, imagine starting a mountain bicycle with its front gear at its biggest and the back gear at it smallest.