Coast in gear or in neutral?

[Fat Charlie]

Originally Posted by adam728

My Mazda is a prime example, lift your foot off the gas at 55 and the short gearing engine brakes you to 35 (injectors off the whole time) in the same distance that it would coast down to only 47-48 mph or so in neutral. So I'll actually have to get back on the throttle to make it to the intersection on the way to work, using more gas than an engine off neutral coast would. But that still doesn't mean its burning fuel while coasting down.

That's the way Congress does its accounting. They compare how much a 1000 foot high border fence with frickin' laser beams would cost ($infinite) to how much money their proposal for a 500 foot fence would spend over a holiday weekend ($0) and announce their proposal as a cost cutting measure, ignoring the fact that a 500 foot high fence is still excessive. Your approach to the intersection on the way to work involves the same accounting stunt. You hit the engine brake and say "look Ma, no gas!" right before you have to hit the gas again to make it to your stop. You accomplish a few moments of zero gas being burned at the expense of burning more gas on your trip.

So yes, you are burning gas even if it doesn't look like it at the moment because the way you get the few moments of zero increases the amount of gas you have to burn on the way to your intersection. I worded it exactly the way I meant it.

[dirtydave]

I would say neutral engine off is the best way to travel. Idle in neutral would be second. Slowing down in gear would be next followed by pressing the brake following hitting the gas and brake at the same time.

When you are in gear and off the throttle you are engine breakin.and that's bad. Just don't use the brakes you will slow down the car when you do that. Only do it if you need to slow down.

I think there is like 1000 other threads with the same title. The entire community can't agree but if you are listening to information from a tv show I think you should do some more research. If I'm not mistaken many new cars are throwing out engine braking or dfco in favor of neutral. Audi comes to mind.

I also would like to add my girlfriend has gotten +3mpg in her automatic 2.5l v5 jetta coasting in neutral vs in gear. She is slowly picking up the hypermilling game one technique at a time.