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Old 08-01-2010, 11:17 AM   #181
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Originally Posted by sickpuppy1 View Post
That being said, I don't know why, but I always wonder if putting it in neutral and coasting is bad on the tranny, any thoughts, remember its an AT
It is not recomended that you put your transmission in neutral if your transmission is automatic. The transmission could overheat because there are no oil moving in the transmission if in neutral. Manual transmission dont have this problem.

If someone could confirm
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Old 08-01-2010, 11:33 AM   #182
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I know you shouldnt if the motor is not running and your coasting, but if memory serves me, the pump is running all the time, even in neutral.
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Old 08-01-2010, 03:20 PM   #183
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Originally Posted by Maxh91 View Post
It is not recomended that you put your transmission in neutral if your transmission is automatic. The transmission could overheat because there are no oil moving in the transmission if in neutral. Manual transmission dont have this problem.

If someone could confirm
I was always taught that moving the transmission from neutral to drive while moving could damage the transmission. The only place to move the tranny is from a dead stop.

Might be urban legend....might be for old trannys that were made by Govt. Motors back in the day....but my Dad taught me this and he was a Mechanical Engineer and I always thought his words were the rule!

So it is my rule!
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Old 08-01-2010, 05:16 PM   #184
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DFCO is not worth giving all the attention people are giving it here. It's just cutting off the tiny bit of idle fuel that cars used to waste while coasting in gear. It's done for emissions control primarily. Nearly every car has it now. No biggie.
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Old 08-01-2010, 09:10 PM   #185
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DFCO is not worth giving all the attention people are giving it here. It's just cutting off the tiny bit of idle fuel that cars used to waste while coasting in gear. It's done for emissions control primarily. Nearly every car has it now. No biggie.
Actually, only around 50% of all cars have it now, and when employed willingly it is a valuable fuel saving tool. I'm surprised to hear you make such a flippant remark regarding something that so easily saves fuel.

Please also remember that for folks that live in hilly areas DFCO is even more useful. For example, when coming down the mountain I can stay in DFCO for several miles at a time. That makes a huge impact over the course of each tank.
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Old 08-02-2010, 11:46 AM   #186
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Originally Posted by BailOut View Post
Actually, only around 50% of all cars have it now, and when employed willingly it is a valuable fuel saving tool. I'm surprised to hear you make such a flippant remark regarding something that so easily saves fuel.

Please also remember that for folks that live in hilly areas DFCO is even more useful. For example, when coming down the mountain I can stay in DFCO for several miles at a time. That makes a huge impact over the course of each tank.
That's a good point. I've seen my average MPG increase when using DFCO downhill.
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Old 08-03-2010, 10:17 AM   #187
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Hi All.

I've been insterestedin DFCO for a while now since Top Gear did a feature on it.
I have adjusted my driving style to encourage the DFCO, but my motives were not to see my MPG improve dramatically and save cash. My view is, if I have a leaky tap, (or fawcet to you guys over the pond :-)), that drips every 20 seconds, it wont add much to my water bill, but why waste the water?

Anyway, I have often wondered if the DFCO can be better used. I have an armchair thoery on utilising it, see what you think. Here is the theory:

Drive at 60mph, let the car engine break down to 50mph in DFCO, gently accellerate back to 60mph. Repeat the cycle.

Now, assuming that the decelleration and accelleration times were equal and on a flat road, would you see an overal improvement in economy, a reduction or no change?
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Old 08-03-2010, 11:25 AM   #188
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Quote:
Originally Posted by Beer Jammer View Post
Hi All.

I've been insterestedin DFCO for a while now since Top Gear did a feature on it.
I have adjusted my driving style to encourage the DFCO, but my motives were not to see my MPG improve dramatically and save cash. My view is, if I have a leaky tap, (or fawcet to you guys over the pond :-)), that drips every 20 seconds, it wont add much to my water bill, but why waste the water?

Anyway, I have often wondered if the DFCO can be better used. I have an armchair thoery on utilising it, see what you think. Here is the theory:

Drive at 60mph, let the car engine break down to 50mph in DFCO, gently accellerate back to 60mph. Repeat the cycle.

Now, assuming that the decelleration and accelleration times were equal and on a flat road, would you see an overal improvement in economy, a reduction or no change?
The theory you described is called pulse and glide (P&G) by hypermilers on CleanMPG. If your target speed is 55 MPH driving from point A to point B using P&G is more fuel efficient than driving at a constant speed on a flat road.
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Old 08-03-2010, 08:31 PM   #189
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Don't you just use the energy you saved "gliding" when "pulsing?" This pulse and glide thing sounds like it defies the laws of conservation of energy, same goes with the mountain driving. Please explain how this is possible.
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Old 08-11-2010, 09:56 PM   #190
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I don't have an RPM gauge.. at what speeds will it be wise to use DFCO? I have been using it, but I'm not sure if it's pointless after I've already slowed.. what speeds are typically above 1100 rpm?
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Old 08-11-2010, 10:25 PM   #191
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In "D" the engine kicks in as high as 30mph, in "3" about 20-25 and in "2" I'm not sure, but it's pretty slow. You can usually feel the engine turn on because all of a sudden you need to apply a little more brake, the car seems to surge.

I love that there's no answer to the laws of conservation of energy, I guess I'll have to raise this little flag here...
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Old 08-11-2010, 10:51 PM   #192
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In "D" the engine kicks in as high as 30mph, in "3" about 20-25 and in "2" I'm not sure, but it's pretty slow. You can usually feel the engine turn on because all of a sudden you need to apply a little more brake, the car seems to surge.

I love that there's no answer to the laws of conservation of energy, I guess I'll have to raise this little flag here...
Assuming all else is equal (average speed etc) I agree with you re. COE however I'm open the possibility that while accelerating the engine is operating at a slightly better average BSFE than when running at the equivalent constant speed. Seems unlikely though and the net benefit needs to be quantified in controlled MPG testing rather than just anecdotal or scanguage feedback before I consider switching off the cruise.
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Old 08-19-2010, 11:49 AM   #193
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Man information is great!
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Old 08-19-2010, 12:03 PM   #194
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Quote:
Originally Posted by Yarisduder View Post
Don't you just use the energy you saved "gliding" when "pulsing?" This pulse and glide thing sounds like it defies the laws of conservation of energy, same goes with the mountain driving. Please explain how this is possible.
When gliding you have an infinite MPG and even though your MPG will drop when slowly accelerating, the average MPG will increase overall compared to driving at a constant speed.

Resources:

http://www.metrompg.com/posts/pulse-and-glide.htm
http://www.greenhybrid.com/discuss/f...se-glide-3700/
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Old 08-26-2010, 12:00 PM   #195
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i have a early 2007 automatic yaris sedan, manufactured in june 2006. can anyone explain what this means, i copied it from the first page of this thread:

"Early versions pf the AT (Including ones sold in the U.S. until around January 2007) can only achieve DFCO with a gear selection lower than (D)rive, i.e. 3 or L, but since half way through the 2007 model year the AT can achieve DFCO in all gears.."

does this mean when i drive around in D that i am never in dfco mode, or does it mean that the dfco only kicks in as the vehicle slows down coasting in a lower gear than D (even though my shifter is still in D)? thanks
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Old 08-26-2010, 02:13 PM   #196
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Hi brg88tx,

Perform the test outlined in the first post to see if yours kicks in DFCO in Drive or if you have to downshift:

Quote:
How can I tell if a vehicle other than the Yaris has DFCO?

Be careful with this test as you may lose Power Steering and Power Brakes during it! Choose the right time and location to perform the test.

On any level or slightly downhill road get up to at least 40 MPH, then start engine braking by keeping the vehicle in gear and letting all the way off the throttle while keeping the clutch disengaged (MT) or keeping the transmission in a gear lower than D (AT). Notice the deceleration force and the sound of the engine.

Now tun off your ignition (This is where you may lose your PS/PB, so be wary!) and watch for any harsher deceleration or change in the pitch of the engine for a few seconds.

If nothing was any different with the ignition turned off then your vehicle uses DFCO. If it decelerated at a different rate or pitch with the ignition off then it does not use DFCO. Do not forget to start your engine back up!
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Old 08-26-2010, 04:15 PM   #197
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As I understand it, it means that DFCO never works when the shifter's in D. But testing it is the only way to be sure for yours. Individual cars often don't match the published specs exactly.
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Old 03-26-2011, 05:19 PM   #198
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dfco

why set cutoff at 21, versus any other figure
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