Engine Off Coasting (EOC) – What is it, when to do it and when not to!

Engine off coasting refers to a method used by “hypermiliers” to increase there miles per gallon (MPG) by shutting off the car while rolling.  Basically let the miles spin while the car is off.

Before you run out find a hill and start coasting, you must be ready to.

Warning: Engine Off Coasting (EOC) is an Advanced Hypermiling Method, do not do this if you don’t know how and are not prepared.  Additionally I will not be held liable for anyone getting hurt or any damage.

Secondly please check your state laws.  Some states permit it, some permit it with restrictions, and others do not permit it at all.

Thirdly, automatic transmissions and EOC do not work well together.  So this is only recommended if you have a manual transmission.

Lastly, if you have power brakes, they will not be as effective when your car is off, so please be careful and pay attention to the traffic in front of you.

OK now that’s out of the way.  Let’s look at a few different methods to employing this method of gas saving madness.

Shut Off

Obviously the first thing we need to do is turn off the car, but before you turn off the car, you need to determine if you should.  It is not going to save much (or any) gas for that matter if you shut off your vehicle and have to turn it back on 5 seconds later.

The most common method used to turn off the car is a quick turn back off the key, before doing so, make sure either the clutch is in or you are in neutral, or both.  Now after you turn off the car, you’ll need to turn the key to the ACC slot on your ignition, this will allow your computer (ECU) to be switched on and most electronics of your car to turn on.  But more importantly it will allow for your odometer to turn! (That’s how you know you are in the right spot)  If it doesn’t turn you’ll still be saving gas, but you won’t be able to track it.

Another method used to turn off your car, is a switch, this can be done many different ways, but most commonly this is done by switching off the fuel pump until the motor dies.  Using this method does not require you to touch the key, as it will still be in the Run position.

Next coast…. and smile!

Turn it on!

OK now what?  Oh yea we have to turn the darn thing back on!  There are two different ways, and there are many opinions on which way is best.  The first and most obvious way is turning the key, which wears the starter.  The second method is what I call “bump starting” which is throwing the car is (5th) gear then pop the clutch out for a second (which can cause wear on the clutch, transmission and sometimes your patience), but if done properly will start your vehicle, rather quickly.

Now for obvious reasons, the first can be done at any time, the second can only be done with a reasonable amount of speed, at least 5MPH, or more depending on your vehicle and your skills.

So that’s it a quick breakdown of EOC (Engine Off Coasting).  Feel free to leave comments, though I must warn you I am no expert, but learning as I go.