Does speed effect your gas milage?

Question

My spouse and I have been having (not arguement) but debate on when a car eats more gas. I drove from denver to trinidad and back doing between 45 in parts of cities passing through and 85 on interstate. I ate a whole tank of gas and half on my round trip. I did atleast 400 miles on that trip. He says the faster you go you dont burn as much gas but I thought the faster you go when accelerating you burn more gas. My spouse drives a suzuki up to his job in the mountains and eats a whole tank of gas a week but if he drove my Chrysler sebring to work in less then a week he would eat all the gas up. Unlike me I can travel to work in my chrysler and use a whole tank in two weeks. So my question is do you eat more gas when your higher speeds or when your stopping and going at lights but doing only like 35 - 45. Someone help us figure out the debate please! :)

Answer 1

Fuel economy goes down when you're in a stop and go type of situation versus a constant higher speed, which is why a car's city mpg rating is lower than its highway mpg rating

Answer 2

When your driving a steady speed on the freeway of 55-60 mph and keep it there you use less gas, but when you do 85 mph your making the engine run faster which is where rpms come into the equation, say you can do 55-60 running 2000 rpms, when you doing 85 mph your engine will be doing 3000 rpms maybe 3500 rpms which will burn more gas.  But driving city will decrease gas mileage a lot the reason for this is stop and go which also increases wear and tear, but the other problem with city driving is your always changing speed your engine also changes speed which the faster that engine goes the more it uses gas. For example your driving and you need to get over but there's no space to go except in front of the first car, so you jump on the gas to pass them the transmission shifts down the engine speeds up to 4500-5000 rpms and holds those rpms for a few seconds you get over in front of the other cars you think you win right, well you still lose the reason is you just burned a lot of gas pulling that little stunt to be able to get over.  Anyway doing the city driving will use more gas because of the stop and go, and highway driving if staying to a speed will always use less gas.  Just so you know rpms is how you measure the engines speed and rpm stands for revolutions per minute in case you didn't know.  Good luck though settling that debate.

Answer 3

Yes, cars burn much more gas on accelerating than cruising so stop and go will burn more gas on any similar car.  Every vehicle has an optimal cruising speed which is typically around 50 - 60 mph where you can get optimal mpg.  The higher you go over that, you mpg will decrease exponentially.

Answer 4

The faster you drive, the higher the engine revs. Engine revolutions are not free. It takes more gas to make the engine run at 2,000 RPM than at 1,000RPM. So driving 85 uses a lot more gas than driving 55. However steady speed driving on the highway doesn't use as much gas as constant start stop driving around town. Getting up to a certain speed uses more gas than just maintaining it does. And idling at a light burns gas but gets you nowhere, therefore it equals zero miles per gallon.

Answer 5

the ideal speed for the most gas efficiency is between 55 and 65 miles an hour.  the more you go above or below that the worse the gas mileage you get

Answer 6

City driving uses the most gas per mile.

However, if you are not stopping regularly, then ideal speed is 55 mph or so.  Faster than that, your fuel economy will go down.  That is why Congress imposed a national speed limit of 55 during the oil embargo.

Answer 7

Technically, around 55 is optimal for mpg. Of course, keeping a steady speed also helps. So, doing the same speed, even if its higher or lower, would get you better gas milage than speeding up and slowing down repeatedly, which is one reason why so many people like cruise control.

Answer 8

The way to get the best gas mileage is to follow the speed limit such as 65mph. Your car burns more gas when you stop and go because you may travel at slower speeds, but your car still uses gas when you are sitting at a stop light. When you look at stickers on new cars, the city mpg is always less than highway mpg.