Recent Topics
Vortec 8.1L Oil Pressure/Filter question
by Burbman
16 minutes 30 seconds ago
1991 Miata Coolant for it?
by tezzzas
29 minutes 12 seconds ago
new obd2 readers
by WhyMe
Today at 11:02 AM
Costco Fell out with Amex
by DBMaster
Today at 10:59 AM
Gasoline vs Diesel Direct Injection
by SVTCobra
Today at 10:30 AM
Picking a different brand of gear oil.
by BrianF
Today at 10:19 AM
Bibi
by salesrep
Today at 10:09 AM
koenigsegg regara, 15000 hp, no gearbox!!!!
by Jeffy_D
Today at 09:55 AM
Clean and/or soak piston rings. Inline honda 4cyl?
by t1snwrbrdr12
Today at 08:46 AM
Observation with DI engine
by Swift101
Today at 08:43 AM
Any a.m. coffee drinkers ever quit ... not easy.
by LoneRanger
Today at 08:28 AM
Friction Modifier needed if track lock defective?
by OlDirty
Today at 07:17 AM
Newest Members
Burbman, Mrmead, JoeStang, mabon, ZPA6
53016 Registered Users
Who's Online
115 registered (29662, Al, Andrei, 1 FMF, AandPDan, Anduril, 5 invisible), 1734 Guests and 284 Spiders online.
Key: Admin, Global Mod, Mod
Forum Stats
53016 Members
66 Forums
227466 Topics
3628623 Posts

Max Online: 2862 @ 07/07/14 03:10 PM
Donate to BITOG
Page 1 of 4 1 2 3 4 >
Topic Options
#3211826 - 12/09/13 11:13 PM Are my habits harmful to this CVT?
gr8gatzby Offline


Registered: 11/22/05
Posts: 590
Loc: Charlotte, NC
My mother drives a 2012 Murano with a super sweet CVT. I've never met a CVT I liked, so for me to say this surprises me. Prior to this she drove a 2004 Murano with a [censored] arse piece-o-garbage how-i-loathed-thee CVT. The mannerisms and personality between these two are night and day, and I am amazed how much can change in a generation.

There is a single negative characteristic that has carried over to the current Nissan CVT: it will not "downshift" when going down hills. For example, I'm travelling 70mph at 2k rpm and approach a 1mi decline, revs stay at 2k rpm for the downward run. Being the engineer nerd that I am, I throw the gearbox to neutral to save this wasted energy and add the extra .0000001 miles to the tank of gas.

A regular geared automatic will drop to near-idle revs when the energy is not needed on a downhill slope. On my stick shift Volvo I drop it in neutral as well.

I am curious, is this shifting to and from neutral at speed doing any long term harm to the transmission? Can my OCD regarding wasted energy be justified? Thanks.


Edited by gr8gatzby (12/09/13 11:14 PM)
_________________________
'95 Ford F150 | 4x4 | 5.8 | 13MPG
'96 Volvo 850 Wagon | I5 | 5SP | 24MPG

Top
#3211828 - 12/09/13 11:14 PM Re: Are my habits harmful to this CVT? [Re: gr8gatzby]
Rand Online   content


Registered: 08/20/03
Posts: 8403
Loc: Barberton,Ohio
you will actually use more gas by putting it in neutral.
_________________________
2015 Forester I-Premium 6MT w/Blizzak ws-80's

Top
#3211832 - 12/09/13 11:18 PM Re: Are my habits harmful to this CVT? [Re: gr8gatzby]
gr8gatzby Offline


Registered: 11/22/05
Posts: 590
Loc: Charlotte, NC
How so? 500rpm vs 2000rpm over 1 mile = less gas.


Edited by gr8gatzby (12/09/13 11:18 PM)
_________________________
'95 Ford F150 | 4x4 | 5.8 | 13MPG
'96 Volvo 850 Wagon | I5 | 5SP | 24MPG

Top
#3211834 - 12/09/13 11:20 PM Re: Are my habits harmful to this CVT? [Re: gr8gatzby]
Shannow Offline


Registered: 12/12/02
Posts: 28038
Loc: a prisoner island
You are, in all likelihood running fuel cut-off on downhill...dropping it into neutral, the engine will be idling, and using fuel.

You will also have some additional load on the brakes which will be costing you money over time (cents likely).

Top
#3211836 - 12/09/13 11:21 PM Re: Are my habits harmful to this CVT? [Re: Rand]
JHZR2 Offline



Registered: 12/14/02
Posts: 35060
Loc: New Jersey
Originally Posted By: Rand
you will actually use more gas by putting it in neutral.



Thats arguable. In theory, yes, you will because the PWM on the injectors will be re-enabled to maintain idle, as opposed to turned off when closed throttle coasting in gear.

However, if at the end of the slope maximum momentum is required, going in neutral will save the pumping losses which effectively act as a brake.

My concern in any AT type vehicle is that the transmission may not be circulating lubricant properly if the pump is on the input shaft, thus causing increased wear. IIRC, only AT vehicles with a pump on the output side can be suitably pulled/coasted without potential for damage.

Top
#3211841 - 12/09/13 11:27 PM Re: Are my habits harmful to this CVT? [Re: gr8gatzby]
gregk24 Offline


Registered: 04/13/13
Posts: 3348
Loc: FL, USA
Doing more harm than good.
_________________________
2006 Honda Accord 2.4 128K
M1 AFE 0w20
Fram Ultra

2005 Chevy Uplander 3.5 122K
VML SB 5w30
Fram Ultra

1991 Buick Park Avenue 3.8 115K
QSD 10w30
Fram TG

Top
#3211856 - 12/09/13 11:49 PM Re: Are my habits harmful to this CVT? [Re: gr8gatzby]
daves87rs Offline


Registered: 02/23/09
Posts: 13962
Loc: Michigan
Honestly can't see it helping much....
_________________________
“The Only Thing Necessary for the Triumph of Evil is that Good Men Do Nothing.”

Top
#3211861 - 12/09/13 11:55 PM Re: Are my habits harmful to this CVT? [Re: gr8gatzby]
CHARLIEBRONSON21 Offline


Registered: 08/28/13
Posts: 557
Loc: MEMPHIS, TN
No "L" slot? My fusion has that...
_________________________
'10 Fusion Hybrid: 5w20 Edge EP/ FU
'15 Civic Si: 0W20 HGMO
'13 Fusion Hybrid: 5w20 PUP/ MC
'14 Odyssey: 0w20 HGMO/ FU
'93 Civic: 5W30 PYB/P1

Top
#3211864 - 12/09/13 11:58 PM Re: Are my habits harmful to this CVT? [Re: gr8gatzby]
actionstan Offline


Registered: 05/22/13
Posts: 475
Loc: Ohio
Originally Posted By: gr8gatzby
How so? 500rpm vs 2000rpm over 1 mile = less gas.


RPM isn't always equal to fuel usage. The computer will call for less fuel usage when rolling down a hill, as there is less strain on the engine. I feel like this is doing more harm than good, and you are better off staying in gear 100% of the time, until you are parking the car.
_________________________
1999 Saturn SL1
2013 KIA Forte

Top
#3211868 - 12/10/13 12:02 AM Re: Are my habits harmful to this CVT? [Re: JHZR2]
bvance554 Offline


Registered: 09/24/12
Posts: 1070
Loc: VA
Originally Posted By: JHZR2
Originally Posted By: Rand
you will actually use more gas by putting it in neutral.



Thats arguable. In theory, yes, you will because the PWM on the injectors will be re-enabled to maintain idle, as opposed to turned off when closed throttle coasting in gear.

However, if at the end of the slope maximum momentum is required, going in neutral will save the pumping losses which effectively act as a brake.

My concern in any AT type vehicle is that the transmission may not be circulating lubricant properly if the pump is on the input shaft, thus causing increased wear. IIRC, only AT vehicles with a pump on the output side can be suitably pulled/coasted without potential for damage.


Its not arguable. Leaving it in gear and coasting you will use zero gas, versus coasting neutral and using a minimal amount of gas. Given that, there is absolutely no reason to coast down hill in neutral. Maybe even a little dumb and unsafe.

Top
#3211876 - 12/10/13 12:09 AM Re: Are my habits harmful to this CVT? [Re: JHZR2]
Shannow Offline


Registered: 12/12/02
Posts: 28038
Loc: a prisoner island
Originally Posted By: JHZR2
My concern in any AT type vehicle is that the transmission may not be circulating lubricant properly if the pump is on the input shaft, thus causing increased wear. IIRC, only AT vehicles with a pump on the output side can be suitably pulled/coasted without potential for damage.


Been through that in my head with the 4L60E in my caprice.

In neutral and idling, the pump is still pumping. On over-run, the power flow might be reversed, but the pump is still spinning and pumping normally...even with the ignition off (or a dead fuel pump), as long as you were coming from an operational state in drive, the pump is still turning and pumping.

All scenarios are different from rolling it down a hill with the engine off from the start.

Only ever seen a couple of powerglides and an old humber that could be push started.

Top
#3211877 - 12/10/13 12:09 AM Re: Are my habits harmful to this CVT? [Re: bvance554]
gr8gatzby Offline


Registered: 11/22/05
Posts: 590
Loc: Charlotte, NC
Quote:
Maybe even a little dumb and unsafe.


I agree that it is dumb and unsafe. That is not my quandary.

If I am doing no harm to the CVT by shifting to and from neutral while in motion in an effort to prevent unnecessary revs to the engine, and willing to accept the risks to the safety of myself and my passengers, why not do it?
_________________________
'95 Ford F150 | 4x4 | 5.8 | 13MPG
'96 Volvo 850 Wagon | I5 | 5SP | 24MPG

Top
#3211878 - 12/10/13 12:10 AM Re: Are my habits harmful to this CVT? [Re: gr8gatzby]
Shannow Offline


Registered: 12/12/02
Posts: 28038
Loc: a prisoner island
Because you get a $180 ticket if the cop thinks you are coasting in neutral (in either an auto or manual) in my state.

Top
#3211880 - 12/10/13 12:11 AM Re: Are my habits harmful to this CVT? [Re: Shannow]
gr8gatzby Offline


Registered: 11/22/05
Posts: 590
Loc: Charlotte, NC
Originally Posted By: Shannow
Because you get a $180 ticket if the cop thinks you are coasting in neutral (in either an auto or manual) in my state.


You live in the state of North Korea?
_________________________
'95 Ford F150 | 4x4 | 5.8 | 13MPG
'96 Volvo 850 Wagon | I5 | 5SP | 24MPG

Top
#3211882 - 12/10/13 12:15 AM Re: Are my habits harmful to this CVT? [Re: Shannow]
Kuato Offline


Registered: 10/23/05
Posts: 3457
Loc: Houston TX for the moment
Originally Posted By: Shannow
Because you get a $180 ticket if the cop thinks you are coasting in neutral (in either an auto or manual) in my state.


It's illegal lots of places in the US also.

/hijack
_________________________
Amsoil


04 Jeep Wrangler 2.4 MT 186k
F150 stolen, Subaru Outback Premium arrives mid March


Top
Page 1 of 4 1 2 3 4 >