Driving Economically.

thor

So avoiding 4th and 5th in town center with frequent traffic lights is to be generally recommended if it is difficult to get to around 30mph?

Delivery_Driver

It depends on the engine and gearing.Cars with variable valve timing give a much better spread of torque so you can get away with higher gears at lower speeds.Some cars have lower gear ratios than others and pull better too at low speeds.
You'll know if you are in too high a gear as the car won't want to pull without labouring when you are on the throttle.

andygb

thor wrote: »

So avoiding 4th and 5th in town center with frequent traffic lights is to be generally recommended if it is difficult to get to around 30mph?

I generally find, that in towns, with the occasional traffic lights/queues and all the rest, it is possible to use only second and third gears, by anticipating the traffic ahead. Too many people use first gear to trundle along (in a very lumpy fashion), and fourth gear at below 30 mph (and probably below 1500 RPM). Most cars when warm can pull away quite smoothly in second gear.

Strider590

It's really very simple.....

If it's screams, change up. If it's shaking your teeth out, change down.

Labouring the engine in too high gear, is far worse for fuel economy AND engine wear, than thrashing the nuts off it.

grizzly1911

Whilst I accept that max torque = most efficient don't agree that is the most economical in many instances. Speed/drag has already been mentioned.

You may not need all that torque to be delivered to actually move.

You will need a lot more of your torque to move a loaded vehicle or climb hills than you will to travel on the level.

With modern ECUs/injector systems whilst you may be using fuel slightly less efficiently, if you are using less of it full stop to maintain a given speed (without labouring the engine) must be economic than over revving the engine to maintain max torque if it isn't needed.

Lum

I thought the driving at the max torque RPM thing was about accelerating up to speed. Better to accelerate hard and keep in the engine's power band, than to accelerate more gently at a lower RPM and change up early.

Obviously once you are up to your desired speed, you change into the highest appropriate gear and proceed normally.

Joe_Horner

Yeah, trying to stay near max torque at a steady speed isn't economic for steady speed - only for acceleration, where you need excess power and want to produce that excess as efficiently (in engine terms) as possible, for a short time rather than less efficiently and for longer.

surfsister

Some useful tips here!

Just a couple of questions:

Is mph optimimum speed on dual carriageways for mpg as is always suggested?

So basically it's not best to change up to fourth or fifth asap? I always thought it best to get into as higher gear as possible as quickly as possible.

I get 45mph from my peugeut diesel 306 but more would be good.

Also I rarely completely fill up the car as it drives better and has less weight. Don't carry necessary luggage and try to keep tyres inflated.

worried_jim

surfsister wrote: »

I get 45mph from my peugeut diesel 306 but more would be good.

Only 45mph? Take it to the top of a steep hill and treat yourself!:rotfl:

alastairq

at last fill-up, 48.6 mpg's from a 1.3 mpi petrol Skoda Felicia.