shifting from 'D'to 'N'
#1
shifting from 'D'to 'N'
i heard from somebody that u can save gas by shifting from DRIVE to NEUTRAL when yer goin downhill or approaching a stop sign/red light. basically when u take yer foot off the acceleration. i thought about it for a while and it didnt relly make alot of sense soi decided to search online. some people on other forums say that it relly doesnt save a noticeable amount of gas and that its actually bad for the tranny. other people said that its actually worth it and the damage to the tranny is barely any or none at all. i was just wondering wat u guys think bout this.
#4
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Well, there's been plenty of discussion on it, and people tend to have one of two opinions:
Camp A - Shifting into N is good for the tranny. It lowers the RPMs while you're coasting.
Camp B - Keeping it in gear is better. When the car is in gear and decelerating, the engine is being turned by the wheels, and although it is at a higher RPM, the fuel is being cut off.
Camp A - Shifting into N is good for the tranny. It lowers the RPMs while you're coasting.
Camp B - Keeping it in gear is better. When the car is in gear and decelerating, the engine is being turned by the wheels, and although it is at a higher RPM, the fuel is being cut off.
#5
why would shifting in and out of drive cause transmission problems, unless you go WOT in neutral and dump it into drive?
either way, i really doubt it is going to save that much gas
#6
If your car is engine braking, then you're not saving any gas at all basically. So just leave it in drive. Think about it, while in neutral, your car is basically burning as much gas as at idle. When the car is in gear and engine braking, you're using even less gas because the wheels are causing your engine to cycle and your injectors don't have to fire.
i heard from somebody that u can save gas by shifting from DRIVE to NEUTRAL when yer goin downhill or approaching a stop sign/red light. basically when u take yer foot off the acceleration. i thought about it for a while and it didnt relly make alot of sense soi decided to search online. some people on other forums say that it relly doesnt save a noticeable amount of gas and that its actually bad for the tranny. other people said that its actually worth it and the damage to the tranny is barely any or none at all. i was just wondering wat u guys think bout this.
#7
If your car is engine braking, then you're not saving any gas at all basically. So just leave it in drive. Think about it, while in neutral, your car is basically burning as much gas as at idle. When the car is in gear and engine braking, you're using even less gas because the wheels are causing your engine to cycle and your injectors don't have to fire.
i haven't heard a single car go silent when braking (not taking hybrids into account)
#8
Wide band measures Air / Fuel Ratio... during Decel you are reading off the chart... 25+ when normally you read around 14 - 15 A/F... the sensor basically cuts off because no fuel is being burned...
#9
Go install a wide band and look at the readings while decelerating in gear... the car still makes noise yes, but you are not burning gas...
Wide band measures Air / Fuel Ratio... during Decel you are reading off the chart... 25+ when normally you read around 14 - 15 A/F... the sensor basically cuts off because no fuel is being burned...
Wide band measures Air / Fuel Ratio... during Decel you are reading off the chart... 25+ when normally you read around 14 - 15 A/F... the sensor basically cuts off because no fuel is being burned...
#10
Engine is still cycling so there is still an exhaust note. There was a big debate about this on the Lexus forums and some of the techs basically confirmed this.
On hybrids, doesn't the gas engine totally shut down when the electric motor takes over? As in it is no longer turning?
On hybrids, doesn't the gas engine totally shut down when the electric motor takes over? As in it is no longer turning?
#11
Engine is still cycling so there is still an exhaust note. There was a big debate about this on the Lexus forums and some of the techs basically confirmed this.
On hybrids, doesn't the gas engine totally shut down when the electric motor takes over? As in it is no longer turning?
On hybrids, doesn't the gas engine totally shut down when the electric motor takes over? As in it is no longer turning?
#12
FWIW GM has a system on the new astra that automatically shifts it into neutral when at a stop in order to save gas. yes it is only a .5 savings, but in the interest of CAFE they did it.
#13
#14
At idle, yes it would make a difference. Because on an auto; at idle in drive, the engine is loading against the transmission and brakes. ie, the only thing keeping you from moving is your foot on the brake. But in neutral, there isn't a load on the engine so it would burn less gas. But while coasting downhill, the engine wouldn't be loaded while in D.
#15
there are some computer programs (depending on they type of car you have) that have a Decel Fuel Cut Off (DFCO) feature, but most actually have decel fuel maps
#16
According to the FSM on my IS350, if you release the gas pedal all the way and the engine is turning faster than 2500 rpm, fuel is cut entirely. Fuel turns back on once rpm's drop below 1000. This is the same way for most other modern cars due to emissions, not CAFE. And it's not a new method, some cars since the 1980's have done it. I guess someone could check the Maxima FSM and see if it holds true.
#17
Nissan's (A32/33) don't cut fuel entirely, but the IPW is VERY small, my wideband goes offscale when decelerating like Merlyn's.
http://forums.maxima.org/showpost.ph...2&postcount=32
http://forums.maxima.org/showpost.ph...2&postcount=32
#19
It easier to look at it this way. Think of the engine as a large air compressor. On an air compressor, most of the noise you hear is the movement and compression of air. The engine is the same. Fuel/combustion does play a part in the noise, usually it intensifies the sound. So yes the motor will sound like it's still running, but it doesn't need fuel to make that noise.
I also agree that it's best not to put it in neutral. You really don't save much of anything unless you're coasting down a hill that is like 10 miles long, and even then, it's a very small savings.
S
I also agree that it's best not to put it in neutral. You really don't save much of anything unless you're coasting down a hill that is like 10 miles long, and even then, it's a very small savings.
S
#22
#23
Stop complaining!! You think you're being hit hard by petrol prices. I own two Maximas and I fill them both up once a fortnight. It costs me around $92 for each car because I use 98 octane fuel.
In Australia, in my home city Townsville, I saw at the pump this morning for REGULAR (same as your 88/89) $1.57 a litre. That's $5.95 per US gallon.
Little old New Zealand is $2.10 a litre.. yes that's right.. that's equivalent to $7.96 per US gallon. That's double what you're paying.
How do these people do it? We just do. If we can't afford it we bike, bus, walk.. you name it.
That's the global oil crisis. It's very real people and pretty soon you'll be joining the rest of us.
In Australia, in my home city Townsville, I saw at the pump this morning for REGULAR (same as your 88/89) $1.57 a litre. That's $5.95 per US gallon.
Little old New Zealand is $2.10 a litre.. yes that's right.. that's equivalent to $7.96 per US gallon. That's double what you're paying.
How do these people do it? We just do. If we can't afford it we bike, bus, walk.. you name it.
That's the global oil crisis. It's very real people and pretty soon you'll be joining the rest of us.
Last edited by jordandalley; 06-24-2008 at 03:22 PM.
#24
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