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-   -   Eoc (https://www.fuelly.com/forums/f33/eoc-9243.html)

goofy1 07-02-2008 03:37 AM
Eoc
 
i was reading my cars maunal and it says that the car when towed should not be towed with the front wheels on the ground, because of serious damage to the transmission. So i take it that EOC is out of the question so i don't mess up the tranny, right? and if so is there another option besidies pulse & glide in gear?

Jay2TheRescue 07-02-2008 03:43 AM
Quote:
Originally Posted by goofy1 (Post 109155)
i was reading my cars maunal and it says that the car when towed should not be towed with the front wheels on the ground, because of serious damage to the transmission. So i take it that EOC is out of the question so i don't mess up the tranny, right? and if so is there another option besidies pulse & glide in gear?
You can shift into N without shutting off the engine. This keeps the fluid pumps operating in the transmission.

goofy1 07-02-2008 11:35 AM
well i tried that for a week, shifting to n and coast with the engine on and i got worse mpg. so i stopped that.

kamesama980 07-02-2008 11:49 AM
your car is new enough to have DFCO hence the worse mpg.

grey 07-02-2008 01:38 PM
Quote:
Originally Posted by goofy1 (Post 109155)
i was reading my cars maunal and it says that the car when towed should not be towed with the front wheels on the ground, because of serious damage to the transmission. So i take it that EOC is out of the question so i don't mess up the tranny, right? and if so is there another option besidies pulse & glide in gear?

If you have an automatic, then dont coast in Neutral.

I dont know why people on here say it is okay... maybe they are rebuilt transmission salesmen.

palemelanesian 07-02-2008 01:43 PM
Coasting in neutral is FINE if the engine is running. No problem whatsoever. Automatics will frequently do this on their own. Just watch the tachometer drop to idle as you roll up to a stop - that's neutral.

In this case, coasting with the engine off is bad. Just make use of what you can do. I suggest trying engine-on coasting again. It's amazing how little bits of 150mpg will raise your trip average.

You might consider a Scangauge to show you how and when to use this, though.

theholycow 07-02-2008 02:01 PM
Quote:
Originally Posted by goofy1 (Post 109237)
well i tried that for a week, shifting to n and coast with the engine on and i got worse mpg. so i stopped that.
It may be that it won't work for you, or you may not be using the strategy right. It can be a little confusing trying to find right the way to use it.

Quote:
Originally Posted by kamesama980 (Post 109239)
your car is new enough to have DFCO hence the worse mpg.
DFCO is not a substitute for neutral coasting. They're complimentary. DFCO is great if you intend to slow or stop. Neutral coasting is better if you don't.

See, you have a certain amount of kinetic energy stored in the car, and idling uses a certain amount of energy stored in fuel. When you DFCO, you use your stored kinetic energy not only to move the car, but to turn the engine a lot faster than necessary, pumping air past a closed throttle and fighting engine friction. When you neutral coast, you use less energy all total; the amount of gas you spend idling is less than the amount of gas you'd have to spend later if you had chosen DFCO instead.

Quote:
Originally Posted by grey (Post 109260)
If you have an automatic, then dont coast in Neutral.

I dont know why people on here say it is okay... maybe they are rebuilt transmission salesmen.
I don't know where this FUD comes from...maybe from oil salesmen. There is no reason why neutral coasting in an automatic would cause a problem. The issue was thoroughly discussed in another thread:
https://www.gassavers.org/showthread.php?t=8150

Quote:
Originally Posted by PaleMelanesian (Post 109264)
Automatics will frequently do this on their own. Just watch the tachometer drop to idle as you roll up to a stop - that's neutral.
I don't know where this piece of misinformation continually comes from either. Check the same thread I link above. Automatic transmissions do NOT enter neutral unless you shift to N. They remain in gear, and the torque converter unlocks; it still transmits some power, but the fluid coupling allows the car to be stopped while the engine continues running. This is why it saves gas to put it in N while stopped instead of staying in D. I've watched my fuel rate meter in my automatic as I wait at a stop in D and N, and fuel rate definitely goes down in N while RPM stays the same.

Quote:
Originally Posted by PaleMelanesian (Post 109264)
In this case, coasting with the engine off is bad. Just make use of what you can do. I suggest trying engine-on coasting again. It's amazing how little bits of 150mpg will raise your trip average.

You might consider a Scangauge to show you how and when to use this, though.
This part is 100% correct.

palemelanesian 07-02-2008 02:10 PM
Quote:
Originally Posted by theholycow (Post 109268)
it saves gas to put it in N while stopped instead of staying in D. I've watched my fuel rate meter in my automatic as I wait at a stop in D and N, and fuel rate definitely goes down in N while RPM stays the same.
I've seen the same. I was (unclearly, you're right) talking about as you're moving at, say, 20mph. It's not the same as neutral, but the effects are similar. Engine and wheels are moving at different speeds, and the transmission is just fine.

theholycow 07-02-2008 02:23 PM
Quote:
Originally Posted by PaleMelanesian (Post 109271)
I've seen the same. I was (unclearly, you're right) talking about as you're moving at, say, 20mph. It's not the same as neutral, but the effects are similar. Engine and wheels are moving at different speeds, and the transmission is just fine.
Even then, in most vehicles, the engine won't go all the way down to idle. In fact, even in N while at speed many won't go all the way down to idle (due to fluid resistance inside the transmission, I think).

The effect is similar but it doesn't demonstrate the safety of neutral coasting. Nonetheless, neutral coasting is safe in common automatic transmissions. I've never ever heard of anyone for whom it caused a problem.

grey 07-02-2008 02:55 PM
Quote:
Originally Posted by theholycow (Post 109274)
Nonetheless, neutral coasting is safe in common automatic transmissions. I've never ever heard of anyone for whom it caused a problem.
oh well, highly scientific research is hard to dispute...
ask a person who knows, such as a reputable transmission mechanic.

theholycow 07-02-2008 03:30 PM
Quote:
Originally Posted by grey (Post 109278)
oh well, highly scientific research is hard to dispute...
ask a person who knows, such as a reputable transmission mechanic.
What causes the failure? How does it fail?

grey 07-02-2008 08:44 PM
Quote:
Originally Posted by theholycow (Post 109282)
What causes the failure? How does it fail?
as with most transmission failures, HEAT

To be fair I did a search to see why this bit of information is not widely known. This took 14 seconds to find:

action.publicbroadcasting.net/cartalk/posts/list/669010.page
In short, don't do it.

The tranny hydraulic pump is driven by the input shaft from the torque convertor. Therefore if the output shaft is spinning at 50mph and the engine is idling it won't be delivering the required pressure to the tranny. It's the same as running your engine at 3000rpm with an oil pump delivering 1000rpm of oil pressure. The result is increased wear, burnt tranny fluid and a premature visit to the tranny shop.

Plus it's dangerous, vehicle dynamics are balanced around an on load system, when you unload that system - coasting in neutral, the vehicle is inherently unstable. Try a sharp turn in neutral sometime and you'll get the idea.

goofy1 07-03-2008 04:44 AM
i will say this. when i coasted in D for example getting up to 60mph and then coasting until 50-55mph i got 37.5 mpg. thinking that coasting in N since i could go futher, doing the same speed my mpg went down to 36 down more to 33. but with a scangauge or the like to see whats going on. i'm going to have to stay with coasting in D since i know that works. you all can see my gaslog and see it go down

theholycow 07-03-2008 06:49 AM
Quote:
Originally Posted by grey (Post 109326)
To be fair I did a search to see why this bit of information is not widely known. This took 14 seconds to find:

action.publicbroadcasting.net/cartalk/posts/list/669010.page
So? It's just another forum. I can find loads of forum replies saying it's okay in the same 14 seconds, probably using exactly the same search terms.

Quote:
The tranny hydraulic pump is driven by the input shaft from the torque convertor. Therefore if the output shaft is spinning at 50mph and the engine is idling it won't be delivering the required pressure to the tranny.
My automatic has an idiot light that's known to come on in stages as the transmission gets warm. It comes on long before temperatures cause long-term damage, let alone immediate damage. It has never come on during neutral coasting, even at highway speeds on long down slopes.

Anyway, in D with the torque converter unlocked and your foot off the gas, the engine speed goes WAY down. Depending on your road speed, engine may get very close to idle.

Some people with automatics report that their engine does not go completely down to idle when in N. Perhaps their computer is keeping the speed up to keep the tranny cool, that was one proposed explanation (another being fluid resistance in the tranny transmitting small amounts of power).

Can someone with a tranny temp gauge or ScanGauge give us the straight dope on this? Does your tranny temp go up while neutral coasting, and if so, how much? My ELM327 ought to show up soon, so I'll be able to log some data too.

Quote:
Plus it's dangerous, vehicle dynamics are balanced around an on load system, when you unload that system - coasting in neutral, the vehicle is inherently unstable. Try a sharp turn in neutral sometime and you'll get the idea.
Blah blah blah, same old FUD there. I do dozens of sharp turns in neutral every day with my tires complaining so I don't have to waste any energy by braking before a turn. Handling is the same as being off the gas pedal in an automatic (don't forget that at the speeds we're talking about, the torque converter lets the engine down to ALMOST idle). If you're going so fast around the turn that not having the drive wheels* drag slightly is going to upset stability, you are going WAY too fast.

*: BTW, is your idea for front or rear wheel drive? Having the front wheels drag slightly from engine braking will upset the car differently from having the rear wheels do so...and then there's weight distribution, pavement changes, general differences in the car and the driver...

If you're not confident in your safety while coasting in neutral, then you definitely should not do it. Most people who do neutral coasting are fine, we manage to survive without being able to accelerate away from a deer crossing the road or whatever, and do not have handling problems.

Jay2TheRescue 07-03-2008 07:37 AM
Quote:
Originally Posted by theholycow (Post 109387)
So? It's just another forum. I can find loads of forum replies saying it's okay in the same 14 seconds, probably using exactly the same search terms.



My automatic has an idiot light that's known to come on in stages as the transmission gets warm. It comes on long before temperatures cause long-term damage, let alone immediate damage. It has never come on during neutral coasting, even at highway speeds on long down slopes.

Anyway, in D with the torque converter unlocked and your foot off the gas, the engine speed goes WAY down. Depending on your road speed, engine may get very close to idle.

Some people with automatics report that their engine does not go completely down to idle when in N. Perhaps their computer is keeping the speed up to keep the tranny cool, that was one proposed explanation (another being fluid resistance in the tranny transmitting small amounts of power).

Can someone with a tranny temp gauge or ScanGauge give us the straight dope on this? Does your tranny temp go up while neutral coasting, and if so, how much? My ELM327 ought to show up soon, so I'll be able to log some data too.



Blah blah blah, same old FUD there. I do dozens of sharp turns in neutral every day with my tires complaining so I don't have to waste any energy by braking before a turn. Handling is the same as being off the gas pedal in an automatic (don't forget that at the speeds we're talking about, the torque converter lets the engine down to ALMOST idle). If you're going so fast around the turn that not having the drive wheels* drag slightly is going to upset stability, you are going WAY too fast.

*: BTW, is your idea for front or rear wheel drive? Having the front wheels drag slightly from engine braking will upset the car differently from having the rear wheels do so...and then there's weight distribution, pavement changes, general differences in the car and the driver...

If you're not confident in your safety while coasting in neutral, then you definitely should not do it. Most people who do neutral coasting are fine, we manage to survive without being able to accelerate away from a deer crossing the road or whatever, and do not have handling problems.
On the Beast it takes about half a second total for me to extend my right hand from the wheel, shift to D, and wait for the tranny to engauge before hitting the accelerator. If you don't have this 1/2 second you're probably going to hit the deer anyway.

GasSavers_RoadWarrior 07-03-2008 07:49 AM
Quote:
Originally Posted by grey (Post 109326)
as with most transmission failures, HEAT

To be fair I did a search to see why this bit of information is not widely known. This took 14 seconds to find:

action.publicbroadcasting.net/cartalk/posts/list/669010.page
In short, don't do it.

The tranny hydraulic pump is driven by the input shaft from the torque convertor. Therefore if the output shaft is spinning at 50mph and the engine is idling it won't be delivering the required pressure to the tranny. It's the same as running your engine at 3000rpm with an oil pump delivering 1000rpm of oil pressure. The result is increased wear, burnt tranny fluid and a premature visit to the tranny shop.
Ummmm my transmission pump is driven by the OUTPUT shaft.

theholycow 07-03-2008 08:37 AM
Quote:
Originally Posted by RoadWarrior (Post 109399)
Ummmm my transmission pump is driven by the OUTPUT shaft.
AFAIK, that's not a common design, most automatics are pumped by the input shaft. That makes EOC bad for them but engine-on neutral coasting seems to be fine.

dosco 07-03-2008 08:52 AM
Quote:
Originally Posted by grey (Post 109326)
The tranny hydraulic pump is driven by the input shaft from the torque convertor. Therefore if the output shaft is spinning at 50mph and the engine is idling it won't be delivering the required pressure to the tranny.
But there is no load on the transmission, so what difference does it make?


Quote:
Plus it's dangerous, vehicle dynamics are balanced around an on load system, when you unload that system - coasting in neutral, the vehicle is inherently unstable. Try a sharp turn in neutral sometime and you'll get the idea.
Hahahaha. OK. So did you ever go around a turn driving a stick? You drive around turns by mashing the gas pedal? I doubt it.

The 'vehicle is inherently unstable?' Really? I wonder how I didn't notice that while P&Ging and driving around turns in "N." I mean, of the car is 'inherently unstable' it would take an awful lot of work to keep it on the road, right? You don't think I'd notice that? I'm surprised I didn't fling my Camry right off the road with all that unstable-ness.

R.I.D.E. 07-03-2008 10:13 AM
Every auto I have seen the primary pump is driven by flanges off the torque converter, it works whenever the engine is running.

Without the primary pump you are in trouble.

I know it would wreck the early Z trannies to tow them.

regards
gary

SolidLiquidSnake 07-03-2008 12:44 PM
Quote:
Originally Posted by theholycow (Post 109404)
AFAIK, that's not a common design, most automatics are pumped by the input shaft. That makes EOC bad for them but engine-on neutral coasting seems to be fine.
How do you find out about that? I looked in my manual and it says that I can tow my car with the front wheels so does that mean I'm safe to EOC?:confused:

theholycow 07-03-2008 03:21 PM
Quote:
Originally Posted by SolidLiquidSnake (Post 109442)
How do you find out about that? I looked in my manual and it says that I can tow my car with the front wheels so does that mean I'm safe to EOC?:confused:
Your Saturn is front-wheel drive, I'm sure. To clarify, it says you can tow it with all four wheels down, as behind an RV? I'm sure you merely forgot the word "down", but you say "tow my car with the front wheels", which could also mean that the tow truck could lift it by the front wheels.

Anyway, yes, it's good for EOC. AFAIK, Saturn automatic transmissions are more similar to servo-operated manual transmissions than common automatics, due to Saturn's history as a transmission company or something.

Here's the folks who would know:
https://groups.google.com/groups?q=re...vel+saturn+sl2

SolidLiquidSnake 07-03-2008 09:27 PM
Quote:
Originally Posted by theholycow (Post 109465)
Your Saturn is front-wheel drive, I'm sure. To clarify, it says you can tow it with all four wheels down, as behind an RV? I'm sure you merely forgot the word "down", but you say "tow my car with the front wheels", which could also mean that the tow truck could lift it by the front wheels.

Anyway, yes, it's good for EOC. AFAIK, Saturn automatic transmissions are more similar to servo-operated manual transmissions than common automatics, due to Saturn's history as a transmission company or something.

Here's the folks who would know:
https://groups.google.com/groups?q=re...vel+saturn+sl2
Nice, I had the impression that I could, but you clarified the results... Too durnk to be here I can tell..


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