Neutral coasting vs In-Gear coasting

[Netherby]

Hello all,

I'm somewhat curious as to what people have found with coasting in neutral vs in-gear. For example if you travel down a fairly steep hill, putting the clutch in actually lets the car build up more momentum than having it in gear with no throttle. But is the car actually using more fuel while in neutral than it is when the tires are moving faster than the idle speed of the engine?

Which leads to a follow on from that, if you need to come to a stop is it better to cycle down the gears (engine braking) than to coast in neutral and use the brake?

Cheers!

[NeilBlanchard]

Hello & welcome,

Which way you should coast depends on the situation: if you can carry all your momentum to go as far as possible, then coast in neutral. It does burn some gas this way, but the momentum you gain will carry you farther/longer and so overall it has a higher MPG.

OTOH, if you have to stop at the bottom of the hill, then you should probably use the engine to brake; especially if your vehicle shuts off the fuel while the wheels are spinning the engine (above a minimum RPM). In this situation, you will get higher MPG by using the engine as a brake.