Using DFCO to increase your MPG - Page 3 - Toyota Yaris Forums

uncleyaris · 03-23-2007, 11:03 PM

Quote:

Originally Posted by ChinoCharles

Does this come with that Ebay +20 HP speed module?

Basscat · 03-24-2007, 11:10 PM

I'd have to say it works! Just keeping the technique in mind during my normal driving, on my most recent fillup I got 42.9 MPG, compared to a previous best of 41 and an average of about 38-39. Nothing scientific about my observations, but I'm convinced. I do live in hilly country, which probably makes more of a difference. Thanks for the tip!

hystria · 03-25-2007, 11:10 AM

Quote:

Originally Posted by BailOut

The only mod I have made to my Yaris so far ... I used 2.5oz. of Lucas Fuel Treatment at my second fueling.

My efficiency on that tank was 43.67 MPG.

I totally agree with the use of the DFCO, it also saves the brakes. whenever it's possible put the engine in compression, the car will also be more stable when braking.

About that Lucas treatement, not sure what it does, but one time a mechanic put a bottle of a strong injector cleaner into my civic gas tank, that increased dramatically the mileage, something like 25% more on the highway. now that it's good but it comes with a cost

BMGYaris · 03-25-2007, 11:56 AM

SO WAIt? us AT should never switch it into third over about 55mph?

BailOut · 03-26-2007, 08:26 PM

Quote:

Originally Posted by BMGYaris

SO WAIt? us AT should never switch it into third over about 55mph?

We're not speaking about the passing gear you can invoke by pressing down a bit on the accelerator while in overdrive, but manually selecting "3" on the shift tree.

I'm not positive about 55 MPH as a hard limit but your owner's manual will have the definitive information. Also remember that we're speaking about dropping into "3" for a deceleration effect, meaning it will place a lot of load on the engine that wasn't there just a second before, wile accelerating past 55 MPH in "3" would have built RPM gradually.

This is why I say that 55 MPH is a good cut-off point.

daq421 · 03-29-2007, 02:40 PM

Quote:

Originally Posted by BailOut

[

Does this work on both the manual and automatic transmissions (MT and AT)?

Yes, but it is much more efficient with the MT. The MT can achieve DFCO in any gear as long as the clutch is disengaged (meaning you don't have it pushed in) and your foot is not touching the throttle, while the AT can only achieve DFCO with a gear selection lower than D (overDrive), i.e. 3 or L.

Help me understand this.. I should begin using the 3 - L positions on my A/T Yaris to slow down? This is how to activate the DFCO?

-Peter

BailOut · 03-29-2007, 04:02 PM

Quote:

Originally Posted by daq421

Help me understand this.. I should begin using the 3 - L positions on my A/T Yaris to slow down? This is how to activate the DFCO?

That's correct, whether slowing down for a stop or just trying to maintain a certain velocity (i.e. on a downhill run).

daq421 · 03-29-2007, 04:23 PM

Quote:

Originally Posted by BailOut

That's correct, whether slowing down for a stop or just trying to maintain a certain velocity (i.e. on a downhill run).

Hrrm,

So shifting into 3rd (or lower) won't just create engine braking? Or at least just cause higher revs?

Ok I'll try it..
-Peter

BailOut · 04-07-2007, 09:09 PM

The original post has been updated with solid timing data as well as info on DFCO with a ScanGauge II.

AustinYaris · 04-07-2007, 09:15 PM

I still don't understand how this is more fuel efficient than just coasting in neutral.

churp · 04-07-2007, 09:29 PM

If I understand it right....idling in neutral still has gas going to the engine (small amount but enough to keep it running), while this totally cuts gas off to the engine during this period (nada/none even while the engine is rotating).....correct???

AustinYaris · 04-07-2007, 09:34 PM

Quote:

Originally Posted by churp

If I understand it right....idling in neutral still has gas going to the engine (small amount but enough to keep it running), while this totally cuts gas off to the engine during this period (nada/none even while the engine is rotating).....correct???

I think that's the idea... but regardless... say you're coasting in neutral at 40mph down a gradual incline, you'll maintain that 40mph for much longer in neutral coasting than in 3rd gear. Right?

I would imagine that in 3rd gear... you would come to a slowdown much more quickly having to use more gas.

BailOut · 04-07-2007, 09:43 PM

AustinYaris,

churp hit it dead on. As for costing in N vs. 3 I don't know if you have the AT or MT but with my 5MT I can maintain my speed in a 5th gear DFCO on as little as a 2% grade.

Part of taking advantage of DFCO is selecting the right gear for the scenario. As I've mentioned a few times before this is where the MT really outshines the AT but the AT is by no means unusable for this.

AustinYaris · 04-07-2007, 09:54 PM

Quote:

Originally Posted by BailOut

AustinYaris,

churp hit it dead on. As for costing in N vs. 3 I don't know if you have the AT or MT but with my 5MT I can maintain my speed in a 5th gear DFCO on as little as a 2% grade.

Part of taking advantage of DFCO is selecting the right gear for the scenario. As I've mentioned a few times before this is where the MT really outshines the AT but the AT is by no means unusable for this.

Ah... I see where I was confused... the 3rd gear thing really only applies to AT... I actually have a MT.... So you can use DFCO in the other gears... For some stupid reason, I thought DFCO would work only in 3rd gear regardless of MT or AT.

Anyways.. I just got my Scangauge II today. I'll have to try out this DFCO. I'll post my results in a few days.

esquiva · 04-08-2007, 10:02 AM

hmmmm...i've been doing this ever since...of course to save gas..i know im not using gas coz im not hitting the gas pedal..
....very good information

Lillydot · 04-08-2007, 03:55 PM

something else i'm curious about when using this method: when is the best time to switch back to overdrive? do i switch back before i press my brakes? after i've some to a complete stop? before i press the accelerator again? does it even matter?

BailOut · 04-08-2007, 07:11 PM

Lillydot,

Don't go back into OD until you reach a complete stop or are ready to accelerate again. That way you're sure to get the maximum benefit of a DFCO.

naossoan · 04-12-2007, 02:00 AM

ok, I don't really understand how this would work.

How does it completely cut off fuel flow? Won't the engine stall? Or is that the point?

If you're coasting in 4th gear foot off the gas it shuts off the engine...but then when you touch the gas it starts the engine back up again?

How can the engine keep turning over when there is no fuel to ignite and push the cylindars back down?

I'm confused.

04-07-2007, 09:09 PM	#45
BailOut Steals terrorist's lunch View User's Garage Drives: 2007 Yaris Liftback Join Date: Mar 2007 Location: Reno, Nevada, USA Posts: 1,299	The original post has been updated with solid timing data as well as info on DFCO with a ScanGauge II. __________________ - Brian Share the Road I often carry 2 carpool passengers and mountain bikes or snowboards/skis over a 4,500 foot elevation difference. Click the graphic above to see my detailed mileage logs.

04-07-2007, 09:15 PM	#46
AustinYaris View User's Garage Drives: 2007 Yaris LB Manual Join Date: Apr 2007 Location: Austin, TX Posts: 39	I still don't understand how this is more fuel efficient than just coasting in neutral. __________________

04-07-2007, 09:29 PM	#47
churp Clean and (dis)Functional View User's Garage Drives: Yaris 2dr--Black Betty Join Date: Mar 2007 Location: Tropical Minnesota Posts: 562	If I understand it right....idling in neutral still has gas going to the engine (small amount but enough to keep it running), while this totally cuts gas off to the engine during this period (nada/none even while the engine is rotating).....correct??? __________________ ____________ Old School Cobble Jockey

04-07-2007, 09:43 PM	#49
BailOut Steals terrorist's lunch View User's Garage Drives: 2007 Yaris Liftback Join Date: Mar 2007 Location: Reno, Nevada, USA Posts: 1,299	AustinYaris, churp hit it dead on. As for costing in N vs. 3 I don't know if you have the AT or MT but with my 5MT I can maintain my speed in a 5th gear DFCO on as little as a 2% grade. Part of taking advantage of DFCO is selecting the right gear for the scenario. As I've mentioned a few times before this is where the MT really outshines the AT but the AT is by no means unusable for this. __________________ - Brian Share the Road I often carry 2 carpool passengers and mountain bikes or snowboards/skis over a 4,500 foot elevation difference. Click the graphic above to see my detailed mileage logs.

04-08-2007, 10:02 AM	#51
esquiva Noypi ako! View User's Garage Drives: 07 S Sedan 5-Speed M/T Join Date: Aug 2006 Location: South Cali Posts: 226	hmmmm...i've been doing this ever since...of course to save gas..i know im not using gas coz im not hitting the gas pedal.. ....very good information __________________ Nagka-anak sina boy at nene, isang lalaki at isang babae. binata't dalaga na sila... Nene jr.: tay, peram naman ng kotse o... Boy Bastos: sige pero isang kondisyon. mag-ano muna tayo. Nene jr.: tay meron ako ngayon e. blowjob na lang kita. Boy bastos: o sige. pagkatapos ng blowjob... Nene jr.: tay, bat lasang tae yung etits nyo? Boy bastos: ah ganon ba? hiniram kasi ng kuya mo kanina yung kotse e!

03-24-2007, 11:10 PM	#38
Basscat Drives: 2007 Yaris S Sedan Join Date: May 2006 Location: Missouri, USA Posts: 16	I'd have to say it works! Just keeping the technique in mind during my normal driving, on my most recent fillup I got 42.9 MPG, compared to a previous best of 41 and an average of about 38-39. Nothing scientific about my observations, but I'm convinced. I do live in hilly country, which probably makes more of a difference. Thanks for the tip!

03-25-2007, 11:56 AM	#40
BMGYaris Drives: Yaris 3dr Hatchback Join Date: Oct 2006 Location: South Carolina, USA Posts: 255	SO WAIt? us AT should never switch it into third over about 55mph?

04-08-2007, 03:55 PM	#52
Lillydot Absolutely Red!!! Drives: 07 A/T Yaris Liftback Join Date: Mar 2007 Location: Boston, MA Posts: 63	something else i'm curious about when using this method: when is the best time to switch back to overdrive? do i switch back before i press my brakes? after i've some to a complete stop? before i press the accelerator again? does it even matter?

04-08-2007, 07:11 PM	#53
BailOut Steals terrorist's lunch View User's Garage Drives: 2007 Yaris Liftback Join Date: Mar 2007 Location: Reno, Nevada, USA Posts: 1,299	Lillydot, Don't go back into OD until you reach a complete stop or are ready to accelerate again. That way you're sure to get the maximum benefit of a DFCO. __________________ - Brian Share the Road I often carry 2 carpool passengers and mountain bikes or snowboards/skis over a 4,500 foot elevation difference. Click the graphic above to see my detailed mileage logs.

04-12-2007, 02:00 AM	#54
naossoan Drives: 07 Yaris 3DR Join Date: Apr 2007 Location: MB, Canada Posts: 145	ok, I don't really understand how this would work. How does it completely cut off fuel flow? Won't the engine stall? Or is that the point? If you're coasting in 4th gear foot off the gas it shuts off the engine...but then when you touch the gas it starts the engine back up again? How can the engine keep turning over when there is no fuel to ignite and push the cylindars back down? I'm confused.

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