If I drive 20miles at 30mph and then drive 20miles at 60mph...?

Question

Which journey will use more petrol?

Answer 1

It will depend which gear you drive in.

You should drive in the highest gear possible for the situation you are in. Higher gears are more fuel efficient.

As you should be able to do 30mph and 60mph both in 5th gear - then you will definitely use more at 60mph, even though you will be driving for a shorter length of time.

Answer 2

the road will be a huge factor...if it was flat..then 30mph in fifth= just over idle...if there were stops from 30-0 or 60-0 says it all..at start up 0-30 or 0-60 says it all again..so though it would in theory seem like thirty..would be best..though journey time would increase...

Answer 3

somewhere in top gear with the revs just above tick over is likely to use least fuel. After that,you have to introduce more variables like "which car", its going to be different for each model but the main rule is "Double your speed, quadruple the power required". Apparently, that near to the truth.

. So i'd say the 30 MPH would be better than 60PMH in a smaller car. If you have a 6 or 7 speed car, 60 would probably be better..

Tow a trailer down the motorway and, despite the one tonne load, you will find you get better MPG than driving with no trailer.

Answer 4

That depends on your car.  Most are tuned to cruise at 50mph and use more petrol going faster or slower.  If you have a small car designed for urban use, it will consume less petrol at 30mph.

Answer 5

In SOME cars, the engine is spinning faster at 30 than at 60, because it's not in the highest possible gear or OD.

Check your cars RPM at both speeds and the speed with the lowest RPM will be the best for fuel economy.

Answer 6

Kind of a trick question there. Without any stops, they should technically use roughly the same ammount (could be slightly different depending on your cars gearing at those speeds). The disparity in use of fuel listed for city/highway is mostly due to having to stop the car & get it moving again within city limits. Acceleration of a vehicle uses more fuel than maintaining speed (laws of inertia and all) & accelerating from a complete stop uses substantially more fuel.

Anyway, here in the U.S. speed limits of under 45mph are usually found within city limits. So by association the practical answer (as opposed to the technical answer previously stated)  would be you'd use more fuel going 20miles at 30mph than you would going 20miles at 60mph, due to standard city traffic.

Answer 7

20 miles at 60mph

Answer 8

Its all about diving smoothly and using as little engine revs as possible.A boy racer in his Corsa1200cc will return an avg of 18mpg .I will get 35mpg in my Lexus 3 ltr.Conditions permitting then its an even situation.

Answer 9

This will depend on other variables other than speed.

Answer 10

Cars are built to drive  well at a decent speed,   driving at 60 mph definitely seems more economical.