Fuel economy - Torque vs. Revs

workaccount

So if you are climbing a slight hill. You could hold it in third at higher revs or change to fourth and use that torque but which method uses more fuel?

Marcus.Aurelius

workaccount wrote:

So if you are climbing a slight hill. You could hold it in third at higher revs or change to fourth and use that torque but which method uses more fuel?

If she's struggling, you are probably using more fuel. On a light hill, use the higher gear if it cruises comfortably, if she struggles, drop a gear and accelerate gently.

Hard acceleration in 3rd or 4th on a hill will use a lot of fuel. She will struggle more with the larger cog of 4th and I reckon it will use more fuel than cruising in a more comfortable gear like 3rd. Depends on what you drive to a great extent.

peasant

If the engine actually has to work hard (as opposed to just keep the momentum going) it does so best and most economically at the revs which coincide with maximum torque.

Look it up in your owners handbook, it probably says it somewhwere in the back under technical data ...torque x Nm at Y rpm

Keep your revs in and around that region when going up hills and select the highest gear which still gives you those revs. (i.e if y is 3800 ..you may not reach that in 5th or 4th and have to stay in 3rd) but once you're sitting at the right revs and the car is pulling happily at a reasonable speed, don't stomp the pedal down and try to go faster (unless you really have to) as it will drink fuel then.

When just coasting along you can stay at lower revs/higher gear, as long as you're not labouring the engine

Lord Nikon

Dropping gears if the car is struggling is the best bet. Drop two if need be.
i would risk fuel economy quicker than hurting the engine.