DFCO and Autos - Toyota Yaris Forums

MadMax · 11-08-2008, 11:35 AM

OK, this may have been discussed in the numerous other threads on DFCO and fuel economy; but I was hoping I could get some clarification on how to get DFCO to work with an auto.

In an earlier thread on DFCO, it was believed that you had to tap the brake lightly to get the auto to downshift and engage the DFCO. Is this still the case, or can you simply let off the gas and let it kick in? Or, do you have to manually downshift into 3rd gear to get it to work?

Right now I am "only" getting 35 MPG, but I do have bigger, wider tires (215/45ZR17 Riken Raptor ZRs) which will drop the fuel efficiency a bit; but I drive it very conservatively and mostly at highway speeds, so I was hoping for a little better (and yes, I do adjust my computations for the larger tires). I am hoping that I could utilize the DFCO capability better to improve my mileage.

Cheers! M2

MadMax · 11-08-2008, 02:22 PM

Voodoo

I do add 7% for the added dimension of the larger tire (I had an earlier thread and someone provided a web site that gave me that number), and that is calculated into my figures.

It would seem logical that the DCO would kick in when you let off the gas, but I was wondering if anyone has ever tested it with a ScanGauge II on an auto...

Cheers! M2

PreciousPups4U · 11-08-2008, 03:43 PM

I have an auto and a scangauge. Like voodoo said it kicks in automatically when you take your foot off the gas. DFCO is just a fancy name for coasting seems to me. Course you get the most benefit when going down hill so as not to lose too much speed, but it works when approaching traffic lights and stop signs as well.

I am only averaging 34 mpg by the way with the stock 15" alloys that came with the car. Not much highway driving for me though. Pretty much all city or at least traffic area.

MadMax · 11-08-2008, 06:41 PM

PP4U

Thanks, that's the kind of info I was looking for!

Since I also have a Jeep Wrangler with an auto, so I am always trying to wrangle (pun intended) better mileage out of it. I get 15-16 MPG, another reason I wanted a Yaris to offset it!

Cheers! M2

drummerboy2004 · 11-11-2008, 02:45 AM

DFCO occurs in the auto whenever you are above 1100 RPMs with your foot off of the gas. I have a scanguage, and watch it happen every time. I am not sure about 1st gear though... I never see it happen when I am driving in my neighborhood less than 15 mph. It will read around 50 mpg when I am below 15 foot off the pedal. Hope this helps...
Any other questions feel free to ask.

Matt

MadMax · 11-13-2008, 09:09 AM

OK, I'm a noob...what is FAS and NICE-ON coasting?

Cheers! M2

Revsson · 11-13-2008, 10:37 AM

I had to look them up myself.

Another explaination is at their glossary page:

http://www.cleanmpg.com/forums/glossary.php

FAS = Forced Autostop
ICE = Internal Combustion Engine
NICE-on coasting = Coasting with the car in neutral while ICE running

Whew....learn something new everyday.....hmmm didn't my parent's tell me that?

drummerboy2004 · 11-15-2008, 03:30 PM

Gene,

Thanks for all of the insight. Oh, and I use NICE-ON coasting if I am going downhill or need to coast longer than the DFCO will allow. Yes, DFCO uses less gas, but you cannot glide for that long. There is a section when I am going to school... that if I time it right, I can NICE coast for almost two and a half miles into the school from the main road. DFCO would kill the speed about 3/4 of a mile into it. Then I would have to work my way through the gears again, which uses enough gas. They both have their advantages, and I use both when they are needed. I am not being a smart as when I say thanks for the insight either

... It is people like you that help people get more from their cars, whether it be mileage or life... so thanks

Matt

GeneW · 11-19-2008, 03:44 AM

Quote:

Originally Posted by drummerboy2004

Gene,

Thanks for all of the insight. Oh, and I use NICE-ON coasting if I am going downhill or need to coast longer than the DFCO will allow. Yes, DFCO uses less gas, but you cannot glide for that long. There is a section when I am going to school... that if I time it right, I can NICE coast for almost two and a half miles into the school from the main road. DFCO would kill the speed about 3/4 of a mile into it. Then I would have to work my way through the gears again, which uses enough gas. They both have their advantages, and I use both when they are needed. I am not being a smart as when I say thanks for the insight either

... It is people like you that help people get more from their cars, whether it be mileage or life... so thanks

Matt

You're welcome.

Gene

MadMax · 11-22-2008, 02:54 PM

Here's a question for you automatic owners who have a ScanGauge, is it better to downshift from Drive into 3rd when slowing down to increase the RPMs and therefore keep the DFCO engaged? It may also come into play when slowing down on level surfaces where engine braking is more effective compared with coasting down an decline...

Cheers! M2

*Astroman* · 11-22-2008, 03:17 PM

Mine takes a bit to go into DFCO in D, while a quick shift to 3 and then back makes it immediately go into DFCO.

mark2908 · 11-22-2008, 05:36 PM

Quote:

Originally Posted by MadMax

Here's a question for you automatic owners who have a ScanGauge, is it better to downshift from Drive into 3rd when slowing down to increase the RPMs and therefore keep the DFCO engaged? It may also come into play when slowing down on level surfaces where engine braking is more effective compared with coasting down an decline...

Cheers! M2

It depends on how much "braking" you want. DFCO at lower rpm's is less engine braking than at higher rpm's.
DFCO will stay on as long as forward momentum is maintained, down to about 700 rpm in D. (warm engine) I try to keep in DFCO at the lowest rpm or the highest gear possible.
If I still have room and momentum at 700 rpm in D... I shift to 3rd to stay in DFCO a bit longer. I use DFCO on flat terrain and even uphill approaching stops if momentum and time allows.

Mark

GeneW · 11-22-2008, 08:15 PM

Quote:

Originally Posted by mark2908

It depends on how much "braking" you want. DFCO at lower rpm's is less engine braking than at higher rpm's.
DFCO will stay on as long as forward momentum is maintained, down to about 700 rpm in D. (warm engine) I try to keep in DFCO at the lowest rpm or the highest gear possible.
If I still have room and momentum at 700 rpm in D... I shift to 3rd to stay in DFCO a bit longer. I use DFCO on flat terrain and even uphill approaching stops if momentum and time allows.

Mark

I've seen the same thing. except I try to avoid DFCO approaching a hill. I figure that the momentum is like money in the bank which I did not wish to waste.

Gene

MadMax · 11-22-2008, 07:50 PM

Thanks for the replies. The lack of a tach makes it tougher for me to know what my RPMs are, so I am doing this by the seat of my pants...

Cheers! M2

11-08-2008, 11:35 AM	#1
MadMax Drives: 2008 Yaris Liftback (Sprocket) Join Date: Oct 2008 Location: San Antonio, Texas! Posts: 2,799	DFCO and Autos OK, this may have been discussed in the numerous other threads on DFCO and fuel economy; but I was hoping I could get some clarification on how to get DFCO to work with an auto. In an earlier thread on DFCO, it was believed that you had to tap the brake lightly to get the auto to downshift and engage the DFCO. Is this still the case, or can you simply let off the gas and let it kick in? Or, do you have to manually downshift into 3rd gear to get it to work? Right now I am "only" getting 35 MPG, but I do have bigger, wider tires (215/45ZR17 Riken Raptor ZRs) which will drop the fuel efficiency a bit; but I drive it very conservatively and mostly at highway speeds, so I was hoping for a little better (and yes, I do adjust my computations for the larger tires). I am hoping that I could utilize the DFCO capability better to improve my mileage. Cheers! M2

11-08-2008, 03:43 PM	#3
PreciousPups4U I really LOVE this car!!! View User's Garage Drives: 08 Bayou Blue LB AT Join Date: Oct 2008 Location: Lexington, SC USA Posts: 887	I have an auto and a scangauge. Like voodoo said it kicks in automatically when you take your foot off the gas. DFCO is just a fancy name for coasting seems to me. Course you get the most benefit when going down hill so as not to lose too much speed, but it works when approaching traffic lights and stop signs as well. I am only averaging 34 mpg by the way with the stock 15" alloys that came with the car. Not much highway driving for me though. Pretty much all city or at least traffic area. __________________ Cindy “If there are no dogs in Heaven, then when I die I want to go where they went.” - Will Rogers

11-11-2008, 02:45 AM	#5
drummerboy2004 Drives: 2008 Yaris LB Auto Join Date: Nov 2008 Location: Tampa, Fl Posts: 166	DFCO occurs in the auto whenever you are above 1100 RPMs with your foot off of the gas. I have a scanguage, and watch it happen every time. I am not sure about 1st gear though... I never see it happen when I am driving in my neighborhood less than 15 mph. It will read around 50 mpg when I am below 15 foot off the pedal. Hope this helps... Any other questions feel free to ask. Matt __________________

11-15-2008, 03:30 PM	#8
drummerboy2004 Drives: 2008 Yaris LB Auto Join Date: Nov 2008 Location: Tampa, Fl Posts: 166	Gene, Thanks for all of the insight. Oh, and I use NICE-ON coasting if I am going downhill or need to coast longer than the DFCO will allow. Yes, DFCO uses less gas, but you cannot glide for that long. There is a section when I am going to school... that if I time it right, I can NICE coast for almost two and a half miles into the school from the main road. DFCO would kill the speed about 3/4 of a mile into it. Then I would have to work my way through the gears again, which uses enough gas. They both have their advantages, and I use both when they are needed. I am not being a smart as when I say thanks for the insight either... It is people like you that help people get more from their cars, whether it be mileage or life... so thanks Matt __________________

11-22-2008, 03:17 PM	#11
Astroman Modded Moderator View User's Garage Drives: 07 Toyota Yaris, 71 Galaxie Join Date: Mar 2007 Location: Wenatchee, WA Posts: 3,670	Mine takes a bit to go into DFCO in D, while a quick shift to 3 and then back makes it immediately go into DFCO. __________________ Please visit my online store for computer stuff and Official Yarisworld decals!

11-08-2008, 02:22 PM	#2
MadMax Drives: 2008 Yaris Liftback (Sprocket) Join Date: Oct 2008 Location: San Antonio, Texas! Posts: 2,799	Voodoo I do add 7% for the added dimension of the larger tire (I had an earlier thread and someone provided a web site that gave me that number), and that is calculated into my figures. It would seem logical that the DCO would kick in when you let off the gas, but I was wondering if anyone has ever tested it with a ScanGauge II on an auto... Cheers! M2

11-08-2008, 06:41 PM	#4
MadMax Drives: 2008 Yaris Liftback (Sprocket) Join Date: Oct 2008 Location: San Antonio, Texas! Posts: 2,799	PP4U Thanks, that's the kind of info I was looking for! Since I also have a Jeep Wrangler with an auto, so I am always trying to wrangle (pun intended) better mileage out of it. I get 15-16 MPG, another reason I wanted a Yaris to offset it! Cheers! M2

11-13-2008, 09:09 AM	#6
MadMax Drives: 2008 Yaris Liftback (Sprocket) Join Date: Oct 2008 Location: San Antonio, Texas! Posts: 2,799	OK, I'm a noob...what is FAS and NICE-ON coasting? Cheers! M2

11-13-2008, 10:37 AM	#7
Revsson View User's Garage Drives: 2009 Meteorite Metallic LB MT Join Date: Oct 2008 Location: Southeast Wisconsin Posts: 810	I had to look them up myself. Another explaination is at their glossary page: http://www.cleanmpg.com/forums/glossary.php FAS = Forced Autostop ICE = Internal Combustion Engine NICE-on coasting = Coasting with the car in neutral while ICE running Whew....learn something new everyday.....hmmm didn't my parent's tell me that?

11-22-2008, 02:54 PM	#10
MadMax Drives: 2008 Yaris Liftback (Sprocket) Join Date: Oct 2008 Location: San Antonio, Texas! Posts: 2,799	Here's a question for you automatic owners who have a ScanGauge, is it better to downshift from Drive into 3rd when slowing down to increase the RPMs and therefore keep the DFCO engaged? It may also come into play when slowing down on level surfaces where engine braking is more effective compared with coasting down an decline... Cheers! M2

11-22-2008, 07:50 PM	#14
MadMax Drives: 2008 Yaris Liftback (Sprocket) Join Date: Oct 2008 Location: San Antonio, Texas! Posts: 2,799	Thanks for the replies. The lack of a tach makes it tougher for me to know what my RPMs are, so I am doing this by the seat of my pants... Cheers! M2