With ever rising fuel costs, I coast downhill, I THINK i save fuel, what say you???

Question

I have a renault cabriolet coupe and I do a stop start journey for 50 miles through traffic lights. I read the road in order to slow down or coast early. And if the lights change, I change to gears, Am I saving fuel or what! So many conflicting reports, adn mainly about safety.

I must stress that I read the road ahead and the users behind me to keep with the overall flow of traffic and try to ensure I never have to brake quickly.

|Help - i like the rest of you cant afford this any more....

Answer 1

Can you give us some clue as to where you are in the country.... so that I can keep away from you.  A car out of control is not nice, and a person behind the wheel thinking it's smart too  save fuel, and not their spouses and kids inside a runaway vehicle with no engine braking and relying on brakes..................

See when you get charged with dangerous driving and have spent some time in the jail, then you have to sit an extended driving test ( 70mins) try coasting then, my money says, the examiner will stop the vehicle and make you walk back to the test centre......

Answer 2

Believe it or not, you're actually using MORE fuel if you coast downhill than if you just stick it into top gear and take your foot off the gas! In a modern fuel injected car like your Megane, when you come right off the gas, a device called a fuel cut off valve kicks in and almost entirely cuts the fuel supply to the engine, since it's in gear and running courtesy of gravity anyway. When you select neutral or declutch, the engine has to supply enough fuel to maintain the 800rpm-odd idle speed needed, and even more if you've got the aircon, stereo, lights etc on at the time.

The difference will be small, but there will be a difference.

Answer 3

I would think you are saving. When you say coasting I take it you just take your foot off the pedal and are still in full control of the car.

I find buses are more expensive than driving - same for trains.

Answer 4

I agree with Jay c. Also I think it is illegal to coast downhill because technically you are not in control of your car.

Answer 5

Have the tyres at the correct pressure and never exceed 50mph. This will help you save a little bit of fuel :)

Answer 6

I hope that when you say "coasting" you mean that you are just taking your foot off the gas pedal and not knocking your car out of gear or shutting it off completely.

Answer 7

I think you will find the legally you are not in proper control of your car and that is an offence in UK.

Let me put it this way. The servo on your brakes will not be working.  Your power assisted steering  wil not be working properly. You can not use engine compression to slow down if and when you do brake.

At best you are not being wise.

Answer 8

According to the POLICE

If your coasting, you are technically NOT in charge of the vehicle and could loose control

You may save petrol,  but you may rip the gearbox apart if you forget what gear you should be in for speed when you want to re engage engine + drive

Answer 9

I don't think you are saving enough fuel to justify the time and effort put into it.  I like to save fuel, but this idea that you can gain much with little effort just isn't going to pay off.  Find something bigger if you really care about gas such as carpooling, bus, fewer trips, etc.  You can also measure your gas mileage after doing it for a few days.  I think you will find that the fluctuations in gas mileage are large enough that any gains from what you are doing will be undetectable.

Answer 10

Ah BUT think of the fuel you burn MORE OF every time you turn your engine back on ! LOL