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Author Topic: Anyone shifting to neutral on downhill to save gas ? Back to Topics
Vibe03
Veteran Author
Toronto

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Message Posted: Jul 21, 2010 9:12:55 AM

When it is not steep downhill and you don't need to brake the car to slow it down, coasting down around 55 mph at idling gives the engine a rest also save gas. Just not sure if the vacuum and other stuff are operating at normal level
REPLIES (newest first) Post a Reply
HideMKE
Champion Author Milwaukee

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Message Posted: Mar 4, 2015 12:31:46 PM

never
carinthuist
Champion Author San Francisco

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Message Posted: Mar 4, 2015 7:30:11 AM

no
BCNU
Champion Author British Columbia

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Message Posted: Mar 4, 2015 5:52:28 AM

Time yo sell the car if you're thinking along those lines.
dontuknowOH
Champion Author Ohio

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Message Posted: Mar 3, 2015 12:15:24 PM

What's really "Funny " is that most people labeled as "cheap-skates" they most always often have the extra fuel saved money then to spend on other tangible merchandise that lasts longer then tail-pipe fumes. I Love that benefit... Stay Happy! I drive automatics.... and still extend motion!
JCM54
Veteran Author Los Angeles

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Message Posted: Mar 2, 2015 10:54:04 PM

You gotta have a manual transmission car and be true cheapskate.
StArrow68
Champion Author Oakland

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Message Posted: Mar 2, 2015 9:13:44 PM

Old wives tales just won't die. Not stupid for anyone who knows what they are doing and not hard on a manual transmission since being in neutral is something they are designed for. Be specific but read back through the thread before posting common wisdom that has very little merit in the real world.
twt
Champion Author Virginia Beach

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Message Posted: Mar 2, 2015 3:40:33 PM

Stupid. Hard on the transmission.
poetdog73
Champion Author Toledo

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Message Posted: Mar 2, 2015 9:43:17 AM

not me...flatlander!
b899
Champion Author Connecticut

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Message Posted: Mar 2, 2015 7:49:11 AM

no
BCNU
Champion Author British Columbia

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Message Posted: Feb 28, 2015 1:26:14 AM

hahaha
b899
Champion Author Connecticut

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Message Posted: Feb 27, 2015 8:18:40 AM

no
jitsu
Rookie Author New York

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Message Posted: Feb 27, 2015 6:56:13 AM

No way!
dontuknowOH
Champion Author Ohio

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Message Posted: Feb 27, 2015 6:28:50 AM

My DEFCO circuits probably do go into effect during a release of the go pedal on only some down-grades. With an AWD small size engine it depends on what the tranny is doing in the down-shift-ing of the automatic function of the governor tranny control/ECM monitors/engine rpms, then dropping.

The EFI system is always controlled by the ECM to keep tail-pipe emissions in check, still a 4 cylinder uses very little idle fuel when operating at normal hot on warm days.

I just remember that My vehicle's engine has a near 3:1 advantage to compression brake/kill off momentum speed, when in drive mode, along with drive-train final gearing friction >>> = a fuel disadvantage to ground coverage in mileage. As opposed to a free gravity event(99 MPG. readings) on the FEC indicator @ near 850 RPMs with engine relaxed..... but not Snoring! The alternator also has an somewhat load advantage near 3:1 ratio to decelerate the motion also. A necessary energy(fuel eater) now/then!
Mikeyy1960
All-Star Author Cape Coral

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Message Posted: Feb 26, 2015 2:46:02 PM

yes
StArrow68
Champion Author Oakland

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Message Posted: Feb 26, 2015 2:19:33 PM

The theory that removing your foot from the throttle will shut off the gas is subject to some questions. My instant mpg reading when I'm in neutral at 65mph going down a slight off ramp climbs all the way to 99mpg, while when I just take my foot off the gas the reading only gets up into the mid 80's mpg. Some how the engineer that programmed the system doesn't seem to think that the gas flow is shut off when decelerating in gear. But then again I'm not an engineer.
Enjoy what you drive.
b899
Champion Author Connecticut

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Message Posted: Feb 26, 2015 8:45:14 AM

no
b899
Champion Author Connecticut

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Message Posted: Feb 23, 2015 9:08:33 AM

no
BCNU
Champion Author British Columbia

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Message Posted: Feb 22, 2015 4:12:39 AM

no
redfish67
Champion Author Dallas

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Message Posted: Feb 20, 2015 1:20:00 PM

no
ggg452
Champion Author Manitoba

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Message Posted: Feb 20, 2015 11:53:42 AM

No...driver control?????
Gabilondo
Champion Author New Mexico

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Message Posted: Feb 20, 2015 10:58:41 AM

I do.
b899
Champion Author Connecticut

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Message Posted: Feb 20, 2015 9:26:50 AM

no
b899
Champion Author Connecticut

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Message Posted: Feb 19, 2015 9:09:00 AM

no
SRT8TX
Champion Author Dallas

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Message Posted: Feb 19, 2015 3:02:44 AM

No
Newfoundlander
Champion Author Newfoundland

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Message Posted: Feb 18, 2015 9:00:12 PM

nope
JohnCur
All-Star Author New Jersey

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Message Posted: Feb 18, 2015 11:49:13 AM

no
Vin63
Champion Author San Bernardino

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Message Posted: Feb 18, 2015 10:44:39 AM

No, my common rail fuel injection stops injecting fuel when in gear going downhill. Shifting to neutral sets the fuel system to idle and burns fuel.
MustangGas1964
Rookie Author California

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Message Posted: Feb 17, 2015 2:22:56 PM

they say it is bad for auto. trans.
carinthuist
Champion Author San Francisco

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Message Posted: Feb 17, 2015 11:30:16 AM

no
WEDDY
Champion Author Phoenix

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Message Posted: Feb 17, 2015 9:05:48 AM

No
b899
Champion Author Connecticut

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Message Posted: Feb 17, 2015 8:54:23 AM

no
BCNU
Champion Author British Columbia

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Message Posted: Feb 17, 2015 4:29:26 AM

no
eyegotgas2
Champion Author British Columbia

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Message Posted: Feb 15, 2015 8:13:13 AM

no
JoeKing
Champion Author Manitoba

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Message Posted: Feb 14, 2015 3:48:17 AM

no
dontuknowOH
Champion Author Ohio

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Message Posted: Feb 13, 2015 5:09:41 PM

No hills lately,few down-grades, Happy with that, and BRrrrr..... weather!
hyeglenn
Champion Author Fresno

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Message Posted: Feb 13, 2015 1:57:43 AM

NO.
PaylessKY
Champion Author Kentucky

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Message Posted: Feb 12, 2015 4:35:58 PM

No
b899
Champion Author Connecticut

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Message Posted: Feb 12, 2015 8:55:21 AM

no
b899
Champion Author Connecticut

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Message Posted: Feb 12, 2015 8:50:40 AM

no
xmstr
Rookie Author Michigan

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Message Posted: Feb 9, 2015 8:02:55 AM

I drive a car with a manual transmission and I tried this for a couple weeks when gas prices were nearing $4/gallon a couple years ago. I never really noticed any increase in mileage. Not worth it IMHO.
RalphHightower
Champion Author South Carolina

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Message Posted: Feb 9, 2015 6:05:48 AM

no
redfish67
Champion Author Dallas

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Message Posted: Feb 8, 2015 10:37:14 AM

no
b899
Champion Author Connecticut

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Message Posted: Feb 8, 2015 8:45:47 AM

no
weddy11
Champion Author Phoenix

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Message Posted: Feb 7, 2015 9:10:01 AM

No
dontuknowOH
Champion Author Ohio

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Message Posted: Feb 7, 2015 9:07:50 AM

I can agree with the vehicle engine acting like a compressor resisting/killing the vehicle's momentum. That momentum which was just previously put into use by a fuel energy cost, a required cost, tail-pipe energy gone when the go pedal was released. Saves brakes.

My vehicles do the same as designed, but when in N... mode travel much farther in mileage per any partial idle minimum cost during compression braking left in drive mode. Repeat resuming momenyum..... = costs.

The much older Over-Drive trannies of the "50's" released the compression drag down effect, that was used in std. transmissions then. Momentum back then was sustained while fuel was near $.17 per gal. I think the common new developed bicycle coaster brake system was a clue for saving fuel. It worked as good as the Water Wheel.
b899
Champion Author Connecticut

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Message Posted: Feb 6, 2015 9:08:17 AM

no
Calavera
Rookie Author Indiana

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Message Posted: Feb 4, 2015 4:21:29 PM

Nope, I don't think it is good to do that with an automatic transmission. I will let my foot off the gas or give it a very slight amount of gas to gain extra speed so I don't have to give it much or any pedal to make it back uphill
speedfreek
Rookie Author Edmonton

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Message Posted: Feb 4, 2015 11:49:08 AM

If you have an automatic with electronic fuel injection, rolling downhill should put the ecm into 100% fuel trim so you're not using any fuel and the engine is acting as a compressor...
Skyjunky
All-Star Author Portland

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Message Posted: Feb 4, 2015 6:22:41 AM

nope
hoopitup2000
Champion Author Virginia

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Message Posted: Feb 4, 2015 6:16:28 AM

Rarely. Would rather DFCO when possible.
sparrowfan
Veteran Author Long Island

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Message Posted: Feb 4, 2015 5:32:09 AM

lots of times, but not to save the gas
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