engine speed versus fuel consumption

[Thunderchild]

ok so am about to get a car. now obviously I know that to be as economical as possible I need to get into 5th gear as much as possible but I also know that the engine is more powerful at higher revs so basically say 5 gear at 1800 rpm is that going to be more costly than 4th at 1800 and not labouring the engine sorry if I'm bad at explaning.

[Dassie]

Basically the higher the revs, the more fuel you'll use and the bigger the engine, the more fuel you'll use. The manufacturer of each car you are considering should have average fuel consumtion figures for that engine.

[Thunderchild]

right so labouring an engine does mean it will use more fuel ?

[clancyblob]

Different engines give their optimum performance at different engine speeds. If you know the revs where you car gives optimum power, then use the rev counter to keep in that band as much as possible. Also don't push that right foot down too hard! Buld up speed gradually. You will soon get a sense of when the engine is running lightly. This is probably the revs where the engine is most efficient.

A good economy and safety tip is to look well ahead so you don't have to be braking hard. It's cost petrol to get to that high speed that you've had to lose through braking. Motorist in a line of traffic who accelerate, and then brake all the time are a menace and waste petrol.

[Thunderchild]

yes I have always been thoughtful of what is ahead and have never over accelerated (I did have a car in Italy by first I meant in England) my last car had its highest output at 4600 revs what I am saying is ok the faster the engine the more consumption because for every turn you need x amount of petrol but do I understand correctly that at peak power output it is goig to use less petrol than say a little slower or being pushed harder say I did the same miles at 3000 revs and 4600 revs at which speed will I use less petrol (in the same gear) ? same number of total revs to get there just done slower or faster