Is it ok to brake after coasting towards a stop?

[SilverCrown9701]

Originally Posted by XYZ

Two comments: Sailing through a stop sign at 15-20 MPH may get you a summons someday. You might save 5 cents worth of fuel, but on the day there is a waiting cop who is stealthier than you that you didn't notice, it may not be worth the fine incurred.

No automatic transmission will be damaged by coasting in neutral to a stop or a "near stop". That means you can safely re-engage into drive in first gear, at under 10 MPH. Rev matching at higher speeds may or may not be detrimental. There is usually no way to tell with absolute certainty. You may not realize it until your transmission needs to be rebuilt. The amount of $ you saved on fuel in coasting will seem a pittance compared to the cost of an A/T rebuild.

I rarely coast through stop signs anymore, it's just not worth the risk.

I will try coasting in neutral and report my findings on my next fill up.

[SilverCrown9701]

Originally Posted by XYZ

Pulse and glide with an A/T basically means getting it up to speed so as to get it into a higher gear, then taking your foot off the gas pedal completely, until you need to accelerate again. It amounts to "coasting" while still in "Drive".

Ah ok! I already do this, so I have been P&Ging all along and never knew it. Awesome!

[niky]

Coasting in Drive or Neutral... I personally don't see much difference in wear, as long as you don't get much slippage or stress on the clutch packs when getting back in gear... like XYZ says, from a stop, it's probably no big deal.

I drove a new MINI last month... in "Green" mode, it automatically goes into neutral when you let off the gas any time you're above 30 km/h. Kind of thumbs its nose at people who declare you will die a horrible death if you coast in neutral at highway speeds!

[Xist]

Originally Posted by niky

I drove a new MINI last month... in "Green" mode, it automatically goes into neutral when you let off the gas any time you're above 30 km/h. Kind of thumbs its nose at people who declare you will die a horrible death if you coast in neutral at highway speeds!

Yes, but in most places in the United States, it is illegal if you do this manually. Also, it sounds like engaging DFCO is quite an achievement.

[niky]

In Sport Mode, it stays in gear. In Normal, it depends... it's less eager to go into neutral... but it seems like it still does.

I also seem to recall manual shifting or small prods of the accelerator or brake make it re-engage the clutch.

[serialk11r]

Originally Posted by Xist

Yes, but in most places in the United States, it is illegal if you do this manually.

Who the hell cares. Seriously. Every time I press the clutch for more than a second I must be breaking the law.

[dirtydave]

How would they even know anyway? Yeah they wouldn't, no one would. My friends riding with me didn't even know I did it until I told them and they were in the car.
"Why do you keep going 60 to 45 over and over again?!"
"Its called Pulse and glide It saves fuel"
"Isn't it better to just go 50??"
"And have my engine on burning fuel the entire time I'm driving?? Hell NO"

[Xist]

I certainly do not encourage anyone to break the law, but this one makes as much sense to me as anything from You Can Get Arrested for That!?.

I was happy to read http://ecomodder.com/forum/showthrea...-mn-29077.html, although that law specifies that it is illegal to coast in neutral down a hill.

[PaleMelanesian]

Originally Posted by XYZ

Pulse and glide with an A/T basically means getting it up to speed so as to get it into a higher gear, then taking your foot off the gas pedal completely, until you need to accelerate again. It amounts to "coasting" while still in "Drive".

In some cases, but not always. For example, Honda automatics will hold it in gear and engine-brake if you leave it in D. That's not coasting. When I drive the Odyssey, I'm constantly shifting D-N-D-N to get any real coasting.

Some vehicles' transmissions are programmed to go into a nearly neutral state automatically, like what you're describing. GM trucks come to mind from my experience.

[XYZ]

Originally Posted by PaleMelanesian

In some cases, but not always. For example, Honda automatics will hold it in gear and engine-brake if you leave it in D. That's not coasting. When I drive the Odyssey, I'm constantly shifting D-N-D-N to get any real coasting.

Some vehicles' transmissions are programmed to go into a nearly neutral state automatically, like what you're describing. GM trucks come to mind from my experience.

Absolutely true. It depends on the design of the transmission, how rudimentary or advanced it is, and how the electronic programs (on more recent years) are monitoring and controlling what it does. Unfortunately, there is no practical way to discover all the subtleties of an automatic transmission until after you have purchased a vehicle and experiment with driving it.

I also agree that it is confusing to call coasting while in Drive "coasting" at all. But compared to driving with your foot constantly on the gas pedal, it probably is somewhat more beneficial.