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11-08-2008, 11:35 AM | #1 |
Drives: 2008 Yaris Liftback (Sprocket) Join Date: Oct 2008
Location: San Antonio, Texas!
Posts: 2,799
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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, 02:03 PM | #2 |
Drives: Yaris Sedan (auto) Join Date: Jun 2007
Location: Toronto, Ontario
Posts: 545
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Keep in mind that your new tire circumference will also affect your numbers. If your Yaris came with 15" rims you'll be getting numbers 3.7% lower when calculating your FE, but if your Yaris came with 14" tires your FE readings will be 7.2% off.
If you haven't taken this into account and your Yaris came with 14" rims your 35mpg is actually 37.5mpg. I don't know how much of a hit, but add that initial inaccuracy in calculations on top of the affect of your much bigger tires and rims and you could easily be hurting yourself by reduced FE b/c of the plus size setup and miscalculations by over 10%. On DFCO; from what I've read; it engages as soon as you take your foot off the gas and your engine remains above 1100 rpms or thereabouts... |
11-08-2008, 02:22 PM | #3 |
Drives: 2008 Yaris Liftback (Sprocket) Join Date: Oct 2008
Location: San Antonio, Texas!
Posts: 2,799
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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, 03:43 PM | #4 |
I really LOVE this car!!!
Drives: 08 Bayou Blue LB AT Join Date: Oct 2008
Location: Lexington, SC USA
Posts: 887
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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. |
11-08-2008, 06:41 PM | #5 |
Drives: 2008 Yaris Liftback (Sprocket) Join Date: Oct 2008
Location: San Antonio, Texas!
Posts: 2,799
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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 |
11-11-2008, 02:45 AM | #6 |
Drives: 2008 Yaris LB Auto Join Date: Nov 2008
Location: Tampa, Fl
Posts: 166
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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
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11-11-2008, 07:13 AM | #7 |
Drives: Yaris Sedan (auto) Join Date: Jun 2007
Location: Toronto, Ontario
Posts: 545
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Thanks for the feedback about pedal off and slow moving scanguage numbers. I was wondering it foot off the gas and slowly rolling in parking lots and towards stop signs was worth it.
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11-11-2008, 01:08 PM | #8 | |
Drives: 2008 Yaris LB Auto Join Date: Nov 2008
Location: Tampa, Fl
Posts: 166
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Quote:
Matt
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11-11-2008, 01:38 PM | #9 |
Drives: Yaris Sedan (auto) Join Date: Jun 2007
Location: Toronto, Ontario
Posts: 545
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That's an amazing example about how much of a difference effort can make. Way to go.
I've started FASing to my parking space since I start work before nearly everyone. It's kind of fun when you screw it up a little and end up just crawling into your spot. |
11-11-2008, 01:45 PM | #10 | |
Drives: 2008 Yaris LB Auto Join Date: Nov 2008
Location: Tampa, Fl
Posts: 166
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Quote:
Matt
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11-12-2008, 02:55 PM | #11 | |
Banned
Drives: 2008 Yaris Join Date: Oct 2008
Location: Pennsylvania
Posts: 1,034
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Quote:
Gene |
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11-12-2008, 05:02 PM | #12 | |
Drives: 2008 Yaris LB Auto Join Date: Nov 2008
Location: Tampa, Fl
Posts: 166
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Quote:
Thanks, Matt
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11-13-2008, 06:56 AM | #13 | |
Drives: Yaris Sedan (auto) Join Date: Jun 2007
Location: Toronto, Ontario
Posts: 545
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Quote:
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11-13-2008, 06:59 AM | #14 | |
Drives: Yaris Sedan (auto) Join Date: Jun 2007
Location: Toronto, Ontario
Posts: 545
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Quote:
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11-13-2008, 08:30 AM | #15 | |
Drives: 2008 Yaris LB Auto Join Date: Nov 2008
Location: Tampa, Fl
Posts: 166
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Quote:
Matt
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11-13-2008, 09:09 AM | #16 |
Drives: 2008 Yaris Liftback (Sprocket) Join Date: Oct 2008
Location: San Antonio, Texas!
Posts: 2,799
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OK, I'm a noob...what is FAS and NICE-ON coasting?
Cheers! M2 |
11-13-2008, 10:27 AM | #17 |
Drives: Yaris Sedan (auto) Join Date: Jun 2007
Location: Toronto, Ontario
Posts: 545
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For the best list of different techniques and acronyms I've found, check out:
http://www.cleanmpg.com/forums/showthread.php?t=1510 |
11-13-2008, 10:37 AM | #18 |
Drives: 2009 Meteorite Metallic LB MT Join Date: Oct 2008
Location: Southeast Wisconsin
Posts: 810
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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? |
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