I'm saving gas!

[DivideBYZero]

I KID I KID!



EDIT: PSA this is a homage to the 11ty bn threads of type that have appeared in OT in the past.

 

[Don Vito Corleone]

I'm proud to have started the rating of this topic with zero stars.

 

[Zenmervolt]

*first in line for the lynch mob.



ZV

 

[Capt Caveman]

0

 

[MrPickins]

Awww, I came in here hoping to see a newb getting schooled.

(obviously I didn't look at the OP's name before I clicked)

 

[Gillbot]

Joking aside,

With many modern cars, coasting in neutral does nothing. Many cars now have DFCO or Deceleration Fuel Cut Off which removes the fuel supply when the throttle blade is closed and the car is "coasting".

 

[91TTZ]

I once coasted onto a treadmill. I hit the gas, the treadmill started moving to match my speed and I have no idea what happened after that.

 

[Zenmervolt]

Originally posted by: Gillbot
Joking aside,

With many modern cars, coasting in neutral does nothing. Many cars now have DFCO or Deceleration Fuel Cut Off which removes the fuel supply when the throttle blade is closed and the car is "coasting".

We've established that in many threads. In neutral the engine uses gasoline to idle. In gear and coasting the engine uses no fuel.

ZV

 

[exdeath]

if ( RPM > IDLE_RPM && TPS <= EPSILON ) PULSEWIDTH = 0;

 

[DivideBYZero]

Originally posted by: Zenmervolt

Originally posted by: Gillbot
Joking aside,

With many modern cars, coasting in neutral does nothing. Many cars now have DFCO or Deceleration Fuel Cut Off which removes the fuel supply when the throttle blade is closed and the car is "coasting".

We've established that in many threads. In neutral the engine uses gasoline to idle. In gear and coasting the engine uses no fuel.

ZV

DUH! Is the engine turning? Then you're using gas!

 

[Aikouka]

Actually, I do save gas while in neutral in my car and I've mentioned that. One of the two roads that I'll go down in neutral is a decline the entire way (in one direction of course), but the problem is, the CVT in my car locks up at 26mph so at any speed over that, my car is more "like a manual" and if I let it go, it will end up slowing down. So to get it to keep the same speed or more, I have to use the gas. But popping it in neutral will easily get me 60mph+ on this 35mph road .

So in other words, for me to at least go the speed limit on this road coasting in gear vs in neutral, neutral I can let the engine idle and coast, but it's impossible to coast in gear and maintain the speed limit.

Although it's also illegal to coast in neutral in some (if not all?) states.

 

[Demon-Xanth]

Originally posted by: 91TTZ
I once coasted onto a treadmill. I hit the gas, the treadmill started moving to match my speed and I have no idea what happened after that.

I tried that with my truck once. I ended up running over a baby seal. I'm still not sure how though, but someone slashed my tires and carved "FOR THE ENVIRON?" into my paint.

 

[Kirby]

I'll go out on a limb and ask a question, and hopefully you guys won't tear me a new one.


When slowing down, is it better to down shift, in relation to back pressure and hotspot(?don't remember the word) places on the clutch? I know you won't save gas by putting it in neutral, but I was just wondering about the other effects.

 

[Gillbot]

Originally posted by: DivideBYZero

Originally posted by: Zenmervolt

Originally posted by: Gillbot
Joking aside,

With many modern cars, coasting in neutral does nothing. Many cars now have DFCO or Deceleration Fuel Cut Off which removes the fuel supply when the throttle blade is closed and the car is "coasting".

We've established that in many threads. In neutral the engine uses gasoline to idle. In gear and coasting the engine uses no fuel.

ZV

DUH! Is the engine turning? Then you're using gas!

Actually, no. If the throttle blade is closed and the car is moving IN GEAR, the fuel supply is turned off and the momentum of the car keeps the engine turning over.

 

[imported_Truenofan]

your much better off just coasting, than putting it in a lower gear and using engine compression(aka engine braking) puts a little stress on the drivetrain. only on things like a downhill where you cant use coasting because you would accelerate you shouldnt downshift and use that.

 

[Kirby]

Originally posted by: Truenofan
your much better off just coasting, than putting it in a lower gear and using engine compression(aka engine braking) puts a little stress on the drivetrain. only on things like a downhill where you cant use coasting because you would accelerate you shouldnt downshift and use that.

Thanks! :thumbsup:

 

[imported_Truenofan]

http://www.dailyfueleconomytip.com/?p=53
http://www.eriksmartt.com/blog/archives/174
http://www.cartalk.com/content/features/fueleconomy/
http://everything2.com/index.pl?node=engine%20braking

fact of the matter is, you do use fuel when engine braking, its just spraying the idle amount of fuel into the engine.

 

[Zenmervolt]

Originally posted by: Truenofan
http://www.dailyfueleconomytip.com/?p=53
http://www.eriksmartt.com/blog/archives/174
http://www.cartalk.com/content/features/fueleconomy/
http://everything2.com/index.pl?node=engine%20braking

fact of the matter is, you do use fuel when engine braking, its just spraying the idle amount of fuel into the engine.

Wrong. Modern EFI engines turn off ALL fuel injection when engine braking regardless of RPM.

Your first link is clearly from some someone who doesn't understand how a modern EFI engine works.
The second link specifically says, "The engine may even use less fuel under engine braking then it does when coasting in neutral."
The third and fourth links don't mention a single thing about fuel use under engine braking.

Next time, maybe you should make sure that you're posting links both from reputable sources (hint: among mechanics CarTalk is a joke) and from sources that support the argument you're trying to make. As it is, you've managed to derail your own position.

ZV

 

[DivideBYZero]

Originally posted by: Gillbot

Originally posted by: DivideBYZero

Originally posted by: Zenmervolt

Originally posted by: Gillbot
Joking aside,

With many modern cars, coasting in neutral does nothing. Many cars now have DFCO or Deceleration Fuel Cut Off which removes the fuel supply when the throttle blade is closed and the car is "coasting".

We've established that in many threads. In neutral the engine uses gasoline to idle. In gear and coasting the engine uses no fuel.

ZV

DUH! Is the engine turning? Then you're using gas! <----------------------------OI!

Actually, no. If the throttle blade is closed and the car is moving IN GEAR, the fuel supply is turned off and the momentum of the car keeps the engine turning over.

Umm, I left a stronger clue for you...

 

[nakedfrog]

Aw, man, I was hoping this was the original monstrosity resurrected and moved to the Garage

 

[Oceandevi]

Originally posted by: Demon-Xanth

Originally posted by: 91TTZ
I once coasted onto a treadmill. I hit the gas, the treadmill started moving to match my speed and I have no idea what happened after that.

I tried that with my truck once. I ended up running over a baby seal. I'm still not sure how though, but someone slashed my tires and carved "FOR THE ENVIRON?" into my paint.

Ever seen a grown man naked?

 

[Rubycon]

Here's another question for you knowledgeable car folk:

If going up a grade the driver presses down on the gas but the engine speed does not increase much does the ecu increase the spark power?

I say this because I notice the popping over the AM radio gets noticeably sharper but does not increase in frequency (which is dependent on crankshaft rpm).

 

[Zenmervolt]

Originally posted by: Rubycon
Here's another question for you knowledgeable car folk:

If going up a grade the driver presses down on the gas but the engine speed does not increase much does the ecu increase the spark power?

I say this because I notice the popping over the AM radio gets noticeably sharper but does not increase in frequency (which is dependent on crankshaft rpm).

Spark power is fixed. It is not load or RPM dependent.

What you're hearing through the AM radio is not from the spark, but rather the injector pulses. These will increase as the injector duty cycle is increased to supply extra fuel as the throttle is opened.

ZV

 

[Rubycon]

Originally posted by: Zenmervolt

Spark power is fixed. It is not load or RPM dependent.

What you're hearing through the AM radio is not from the spark, but rather the injector pulses. These will increase as the injector duty cycle is increased to supply extra fuel as the throttle is opened.

ZV

Ok that makes sense as I was wondering what increasing spark power would really do. (I'm not up on cars)

What kind of signal do the injectors get?

 

[imported_Truenofan]

Zenmervolt, give me, what you call a "reputable" source, and enlighten me, instead of stating that im wrong.(it helps when you can prove what you say, instead of saying it, i dont know who you are, if you have any kind of degree's in anything at all. so unless you can prove it, im taking what you say with a grain of salt.)

edit: btw, i know my car still uses gas when im engine braking, im also going to go for automotive repair/tuning when i go to school when i get out.(i plan on doing my own tuning on a standalone system on my car.)