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

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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
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jl1rp
Champion Author New Hampshire

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Message Posted: Dec 20, 2014 9:21:21 PM

no
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redfish67
Champion Author Dallas

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Message Posted: Dec 19, 2014 11:31:30 AM

no
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litesong
Rookie Author Gary

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Message Posted: Dec 19, 2014 10:43:41 AM

My recent car is automatic & I do use my old manual tranny experience to save fuel(presently am averaging 38+mpg, while most drivers of my car get 30mpg). The problems are on steeper hills & my automatic has 6 gears(some auto trannies now have 9 gears). With a manual tranny, you can shift from your traveling gear, directly to the gear needed to get good compression braking. However, with an auto tranny, you have to shift thru every gear to finally get to a gear that gives good compression braking. Its too much shifting. Use your brakes & change your brake pads more often.


[Edited by: litesong at 12/19/2014 10:46:37 AM EST]
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vabites
Champion Author Florida

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Message Posted: Dec 19, 2014 9:28:34 AM

yep, been doing it for decades.
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b899
Champion Author Connecticut

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Message Posted: Dec 19, 2014 9:18:46 AM

no
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StArrow68
Champion Author Oakland

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Message Posted: Dec 17, 2014 12:28:37 PM

My only experience is in a manual shift, no big deal if you know what you're doing and the conditions are correct. Never tried it in an automatic and probably never will.

[Edited by: StArrow68 at 12/17/2014 12:29:18 PM EST]
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JoeKing
Champion Author Manitoba

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Message Posted: Dec 17, 2014 11:04:55 AM

no
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JohnCur
Veteran Author New Jersey

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Message Posted: Dec 17, 2014 12:25:29 AM

Not a good idea with automatic
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StArrow68
Champion Author Oakland

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Message Posted: Dec 16, 2014 7:58:45 PM

Fairly uninformed statement, read below and learn a few things.
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redfish67
Champion Author Dallas

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Message Posted: Dec 16, 2014 10:21:12 AM

stupid idea and it doesn't save any gas
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Jackson126
All-Star Author Virginia

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Message Posted: Dec 16, 2014 7:41:02 AM

no
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JoeKing
Champion Author Manitoba

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Message Posted: Dec 16, 2014 6:25:33 AM

no
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twt
Champion Author Virginia Beach

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Message Posted: Dec 15, 2014 3:05:49 AM

Another BAD idea.
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hoofharted
Champion Author Wyoming

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Message Posted: Dec 15, 2014 1:50:36 AM

no
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b899
Champion Author Connecticut

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Message Posted: Dec 14, 2014 9:14:38 AM

no
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contiki
Champion Author Ontario

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Message Posted: Dec 14, 2014 7:19:23 AM

never..........
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Vibe03
Veteran Author Toronto

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Message Posted: Dec 13, 2014 5:37:51 PM

Never expected such response

I learnt a lot after posting this thread. Of course there are different schools of thoughts but I am just taking the good ones

Hats off to [ dontuknowOH Champion Author Ohio ] for all the interesting stuffs

My Vibe will soon reach 300,000 km and so far only regular maintenance, 4th sets of tires, changed shocks and spring once and 2nd replacement battery coming up soon !

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dontuknowOH
Champion Author Ohio

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Message Posted: Dec 13, 2014 11:00:25 AM

Anytime I can extend My vehicles momentum by taking advantage from a free converted energy source then becomes a benefit. Same goes for a tailwind boost, that will reduce the required amount of fuel use to My engine's duties to propel the vehicle.

Those economy vehicles are aerodynamic, most anyway, have smaller engines that use less idle fuel. The extra ground covered distance, by extending the down-grade momentum travel distance exceeds the small amount of any idle fuel being used, coolant fan E..load energy often is released by relaxing the engines work load on down-grades, all fluids are still in circulation/lubing, and driveline components are free of any extra friction torque loads.

Any brake use at all (not)is minimal including brake lamp energy use and if the tires are inflated proper that becomes a benefit to momentum traveled intervals.

I often only must watch for the other faster travelers that will always be passing Me as a "slower poke" running with the zoned limits + or - 5 MPH. usually! Other stuff including the Wife remains normal, latter does get noisy sometimes like the radio. That radio is "Blessed" with an OFF Button.....
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hoopitup2000
Champion Author Virginia

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Message Posted: Dec 13, 2014 9:54:16 AM

Of course, it's a manual.
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b899
Champion Author Connecticut

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Message Posted: Dec 13, 2014 8:40:16 AM

no
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StArrow68
Champion Author Oakland

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Message Posted: Dec 10, 2014 2:35:09 PM

Now I know that some may dispute that GM engineers know their stuff but in the Corvette if I release the gas pedal on a given down slope the instant mpg reading may get up into the 80s, if however I shift into neutral on the same slope doing the same 65 mph the reading goes to 99.9mpg. Somehow the engineer who programmed the system seems to think the car is getting better mpg.
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Phildog
Champion Author Akron

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Message Posted: Dec 9, 2014 8:22:13 AM

doesn't save gas
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b899
Champion Author Connecticut

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Message Posted: Dec 9, 2014 7:48:36 AM

no
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b899
Champion Author Connecticut

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Message Posted: Dec 8, 2014 8:16:55 AM

no
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Jackson126
All-Star Author Virginia

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Message Posted: Dec 7, 2014 7:53:58 AM

no
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SmoknFord
Champion Author British Columbia

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Message Posted: Dec 6, 2014 11:20:21 PM

never
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Boyrr
Champion Author Allentown

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Message Posted: Dec 6, 2014 11:38:47 AM

nope, a dumb and dumber idea
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dontuknowOH
Champion Author Ohio

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Message Posted: Dec 6, 2014 9:44:41 AM

My car manual reads, approaching steep down grades to manually down-shift the tranny to use E C Braking to control My vehicle with-out excessive brake use.

The driver must make that decision on the speed V/S engine RPM range, whether to go for second or low gear range to hold back their speed. Don't use reverse like some riding lawn cutters drivers/riders do!

Same goes for park when in motion, often shifting the mode lever to the opposite direction (while moving) in the other, places a shock on the tranny's system. Stop first! Hold! one second!

It doesn't always need to be an emergency to down-shift if the owner watches the speed relative with engine RPMs. Cruise must be off!!! Dry roads preferred, wet/slick are risky with-out ABS brakes.

Learn the low range of your engine/tranny travel speed being compatible, KNOW what those speeds are before ever choosing manually selecting LOW RANGE, probably (12 MPH or less than 15 MPH).
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PaylessKY
Champion Author Kentucky

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Message Posted: Dec 6, 2014 8:49:56 AM

No. Its best to never shift an automatic while the vehicle is moving, except in an emergency.
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Garwoodv6
Rookie Author Houston

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Message Posted: Dec 5, 2014 11:11:58 AM

don't worry- the vacuum and other power assist functions work fine as long as the engine is running, even at idle.
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Garwoodv6
Rookie Author Houston

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Message Posted: Dec 5, 2014 11:09:30 AM

Yes.
I also keep an eye out far ahead and coast to traffic lights that will be red or traffic that will force me to slow down or stop. every little bit helps!
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b899
Champion Author Connecticut

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Message Posted: Dec 5, 2014 7:58:50 AM

no
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contiki
Champion Author Ontario

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Message Posted: Dec 5, 2014 6:14:54 AM

Never......
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HideMKE
Champion Author Milwaukee

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Message Posted: Dec 4, 2014 11:57:17 AM

no
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FocusSVT
Champion Author Toronto

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Message Posted: Dec 4, 2014 10:29:40 AM

StArrow68

Agree 100+% what you mentioned. I learnt a lot from this thread and saved
a quite a bit of gas in the last couple years and the engine is running smooth as ever. Over 260,000 km already and so far 2 brake jobs, replace shocks, spark plugs and one battery. No surprise repairs

Have to understand the car though
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b899
Champion Author Connecticut

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Message Posted: Dec 4, 2014 8:44:25 AM

no
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JohnCur
Veteran Author New Jersey

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Message Posted: Dec 4, 2014 12:06:40 AM

ok if stick, not so auto
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redfish67
Champion Author Dallas

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Message Posted: Dec 3, 2014 2:09:56 PM

no
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b899
Champion Author Connecticut

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Message Posted: Dec 3, 2014 8:34:24 AM

no
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captainjoey
Champion Author Maryland

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Message Posted: Nov 30, 2014 10:06:22 AM

I stopped doing that two decades ago.
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Jackson126
All-Star Author Virginia

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Message Posted: Nov 30, 2014 9:37:19 AM

no
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b899
Champion Author Connecticut

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Message Posted: Nov 30, 2014 9:07:19 AM

no
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cv
Champion Author Raleigh

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Message Posted: Nov 29, 2014 6:31:24 AM

I never do that.
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StArrow68
Champion Author Oakland

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Message Posted: Nov 28, 2014 9:28:46 PM

The amount of nonsense here is amazing. Hard on the brakes? Why? There are down slopes where the car will slow under engine braking but will maintain a steady speed when the manual is shifted to neutral, no wear on the brakes at all. Hard on the transmission? Why? With a manual you shift to neutral all the time, especially at idle,
on a down slope you shift to neutral and the engine is at idle, no impact on the tranny. Think about what you are saying.
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dontuknowOH
Champion Author Ohio

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Message Posted: Nov 28, 2014 9:20:23 AM

Never taken time to check the T... gender, believe it's a 6 speed that down-shifts often, has O-Drive (automatic & T/C lock-up, and maybe mech/elect. governors. The O-drive sets-in as low as 30 MPH. but lock-up takes more, varies with engine energy loading.

Any gas saving is over a long time interval, and not a quick realization. Momentum on any down-grade is also affected by total vehicle weight also.
The heavier weight in motion is a factor for heavier duty brake systems.

Most late model vehicles save fuel in drive de-celling when the go pedal is released, and the multi-speed trannies offer less E C braking due to better ECM monitoring/gear selection.
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twt
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Message Posted: Nov 28, 2014 3:03:20 AM

Hard, on the transmission.
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nickless
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Message Posted: Nov 28, 2014 2:25:18 AM

no
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Boyrr
Champion Author Allentown

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Message Posted: Nov 27, 2014 2:23:45 PM

just a bad idea
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jay93LA
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Message Posted: Nov 27, 2014 8:49:51 AM

no
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b899
Champion Author Connecticut

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Message Posted: Nov 27, 2014 8:36:22 AM

no
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b899
Champion Author Connecticut

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Message Posted: Nov 26, 2014 10:00:02 AM

no
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