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-   -   Coasting in Neutral... what if you can't come to a full stop after? (https://ecomodder.com/forum/showthread.php/coasting-neutral-what-if-you-cant-come-full-5425.html)

Sean T. 10-06-2008 01:19 PM

Coasting in Neutral... what if you can't come to a full stop after?
 
So... today I was traveling down my all-time favorite road.

They just repaved it last weekend... omg. so nice. :D

And it is huge up and down hills. The first hill you can coast down for forever, and then a sharp incline to a stop light. I coast down, but can't shift to neutral because I know I can't make it to the top. (I've tried)

After that, there are some short hills followed by a HUGE valley. I can start coasting way back, reach the decline without losing any speed, then increase speed as I go down and retain 80% of that on the way back up. I can make it far enough to get to the stoplight about 1/4 mile after it starts to level back out.

Today, for the first time, I decided to try going down this hill in neutral because I noticed the light on the other side of the valley had just turned red... bad idea. I was about 10 car lengths away when the light turned green.

While this experience has turned me into a huge believer in Neutral Coasting (as soon as I shifted into N, I sped up by 5mpg, with no change in grade)... it also made me think... because I had heard that you should come to a complete stop before shifting into drive, I found myself abruptly coming to a full stop, so I could hurry up and shift into drive without the cars behind me catching up.

So I supposed my conundrum is... what is the best plan of action when you are coasting in neutral and find yourself in a position that doesn't favor you stopping and shifting back into drive?

My thoughts are put on the hazards and pull off onto the shoulder, shift, then merge back into traffic... well, what if there is a curb on each side of the road? Anybody have any thoughts or suggestions on any of this?

Daox 10-06-2008 01:23 PM

Where did you read that you have to stop to put it back into drive? Just rev match as well as you can and put it back in.

Sean T. 10-06-2008 01:38 PM

really? What do you mean by rev match? match them to what?

Sean T. 10-06-2008 01:39 PM

I thought I read it on here... wherever it was it was a long time ago.

Daox 10-06-2008 02:24 PM

Rev match just means to rev the engine up to match the rpm it will be at once it is in gear. This is always a general guess with an automatic. Really, as long as you don't feel the car jerk as it goes back into gear, you are fine.

HondaHound 10-06-2008 02:39 PM

I've been neutral coasting the last couple weeks in my automatic. I haven't noticed much car jerking going back into drive. There were only a couple small instances of this. I've found it very smooth.

HHINLA

Clev 10-06-2008 03:04 PM

Most cars handle the shift into Drive with no problems. The only one that gave me issues was an '08 Kia Rio. (It had other problems anyway; if you shifted from Reverse into Drive if you were rolling backwards at all, it would lock up the tires. I've never had an auto do that before.)

I'll echo what others have said. If it finds the right gear and goes into Drive relatively smoothly, you're fine.

Matt Herring 10-06-2008 03:22 PM

I always give the car a couple seconds to "rev match" after putting it back into drive...especially when neutral coasting at higher speeds (highway or steep downhills). When going from neutral to drive you can see the rpm's go back up to around 1500 from approx. 500...then use the accelerator to ease back up to speed.

trikkonceptz 10-06-2008 04:09 PM

In my situations, I simply drop it back into neutral, the transmission does its own version of rev matching, it will spike the rpms to lets say 2200 befor lowering back down to 1700. SO basically I shift and wait a couple of seconds before engaging the accelerator again.

4 months in to P&G @ highway speeds, no ill effect or wierd noises.

Ford Man 10-06-2008 04:13 PM

My wife's car is an automatic and anytime I nuetral coast in it I just shift back into drive and it always shifts back into gear smoothly, then I just accelerate as normal.


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