[obermd]

Is this a proven fact? Not going to lie but I feel like such a retard doing this going down hills and such, lol.

I have experimented with DFCO and know it will engage from slightly over 1500 RPM all the way up to at least 5000 RPM when you let of the gas for more than a couple of seconds. The injectors are restarted whenever you put the clutch in (manual transmission only), you step on the throttle, or when the engine speed drops to 1200 RPM. You can DFCO in action by switching your car to Metric and watch the instantaneous fuel economy drop to 0 L / 100 KM.

DFCO won't coast as far as neutral, but in many instances its a better solution for coasting than neutral. Whether to use DFCO or neutral depends on how far you are going to coast and what you will be doing at the end of the coast. I have discovered that when not changing gears at the end of the coast I just use DFCO. If I need to downshift sometimes I'll use DFCO and other times I'll make a long slow shift and coast with my clutch on the floor. If I'm stopping I'll use a combination of DFCO, downshifts, and coasting once I get too low for 3rd gear. Coming down the side of a mountain I'm frequently in DFCO in 3rd gear (this is how I know it works to at least 5K RPM) and use the brakes to keep my speed below what the Colorado State Patrol will allow for downhill traffic.

 

[weimerrj]

Well rhodomel, concerning Consumer Reports, we have a certain Prius....enthusiast....who used to pop in quite often and use CR to insinuate just how poor a choice we made buying the Cruze. It's now an official "recommended", so whatever. Our issue then was the very good objective scores contrasted with the poor predicted reliability. They just didn't add up. But he banged that drum, all in the name of "helping" us, you see.

 

[Blue Angel]

Generally speaking, it is good to take advantage of DFCO if you have to slow down or stop anyway, but it's better to coast in neutral down slight grades; the tiny amount of fuel it takes to idle the little 1.4 is more than made up for in extra forward momentum.

If you are already driving above the limit and are flirting with a speeding ticket you won't have any headroom when coasting, but if your speeds are a little lower you can then afford to speed up slightly going down a grade, preserving momentum and coasting for some distance after the hill before your speed returns to normal.

As obermd pointed out, longer and/or steeper grades are a good place to use DFCO since without some sort of braking your speed would get too high, and idling the engine with your foot on the brake doesn't make much sense. Keeping engine revs high enough to keep DFCO engaged (above 1500 RPM) and using the brakes as necessary will be the most efficient way to go.

 

[mknight]

Just wanted to post my news...417 miles...8.76 gallons...47.6mpg!!! Very Happy

90% highway miles, no wind with an Eco MT.

 

[jblackburn]

Speaking of DFCO, does it still kick in with the A/C compressor running?

 

[grs1961]

Speaking of DFCO, does it still kick in with the A/C compressor running?

Yes. At least with my diesel it does.

Also, the diesel cuts the full off sooner, and doesn't switch it back on until ~800rpm.

 

[obermd]

Yes.

 

[zavier]

the idea of getting better fuel mileage is to save energy and money!! so up here in canada upper grades of fuel are quite a bit more costly than base 87 octane fuel. so bear in mind the cost of the fuel as well. is it really saving you money by using it...

fyi. bought a 2013 cruze Lt1. getting abissmal fuel economy. 23 mpg city and 34 hwy. daughters cruze eco is getting low to mid 50 mpg. why is this?!

 

[obermd]

the idea of getting better fuel mileage is to save energy and money!! so up here in canada upper grades of fuel are quite a bit more costly than base 87 octane fuel. so bear in mind the cost of the fuel as well. is it really saving you money by using it...

This is a question that each driver must answer. With a 20 to 25 cent price increase for premium where I live it's definitely less expensive to use premium. As the priced differential goes up it becomes more of a personal decision. Regardless of price, premium will make the Cruze run better - is it enough better to justify spending more is the question. For me, even a 50-60 cent per gallon would be justified, especially in the summer. In the winter I can get away with 87 octane but I prefer to stick with premium year round.

 

[Blue Angel]

...bought a 2013 cruze Lt1. getting abissmal fuel economy. 23 mpg city and 34 hwy. daughters cruze eco is getting low to mid 50 mpg. why is this?!

The way they're driven. I'm sure if you traded cars for a week her 50 MPG Eco's mileage would plummet down to near what you're seeing out of your 1LT, and your car's mileage would jump into the 40's. The Eco does get better mileage, no doubt, but the difference isn't +47% (50/34).

 

[zavier]

I would agree if it wasn't for the fact that her boyfriend is a lead foot and always hard on the throttle! I on the other hand have driven professionally for 26 years and use every trick I've learned over 26 years! I still feel that its a different program in the eco that uses a different fuel map to achieve those economy numbers

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[Blue Angel]

I still feel that its a different program in the eco that uses a different fuel map to achieve those economy numbers

If I remember correctly, the boost map is different on the manual transmission cars. The automatic cars are tuned to have full boost by ~1800 RPM while the manuals have the boost delayed, gradually increasing until ~2500 RPM or so. For around town driving this means far less access to boost at low RPM and higher mileage to boot.

BTW, the boyfriend can't be much of a leadfoot if the Eco is averaging 50 MPG (check my sig). I've been averaging almost 50 MPG lately in my Eco and to do that I have to leave the lead feet in the closet and put on the feather slippers. I do a full throttle 2nd gear pull now and then for the sake of science, but other than that I'm hypermiling this thing.

 

[obermd]

The manuals don't get full turbo boost until 2500 RPM. We do get some turbo assistance below there. In my ECO MT that translates to 82 MPH in 6th gear before full turbo.

 

[StevenJJ]

What is the tire pressure you use? Just saying higher is ambiguous.

 

[obermd]

What is the tire pressure you use? Just saying higher is ambiguous.

I run my ECO's tires at 45 PSI. Max sidewall is 51 for these tires. Any higher and I don't like the ride quality. Any lower and I don't like the handling.

 

[jaystoddard]

Good read, thanks!

 

[warplane95]

I run my ECO's tires at 45 PSI. Max sidewall is 51 for these tires. Any higher and I don't like the ride quality. Any lower and I don't like the handling.

45 psi ?

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[H3LLON3ARTH]

Take em to 51

Sent From An Antique,
My Original Droid.

 

[Macman]

Has anyone used automatic to improve fuel economy?
Automatic - Your Smart Driving Assistant

 

[tdc]

Great post, 'XtremeRevolution'. (Kept for reference). There is one item I'd like to ask about. That is the coolant flowing through the passenger-heater core. In my previous car, the temp slide control has a solid cables inside of a sleeve. It actuates a ball valve in line with the heater core/coolant, allowing a flow of coolant through heater core of: none up to full flow. This effectively reduces the amt of coolant circulating the engine block. I would keep it off until reaching operating temperature, then open it. This decreased the time needed to reach engine (coolant) operating temp and thus begin lean operation sooner. In my 2012 Cruze, don't know if this is the case. I seem to only have a (¿vacuum actuated?) control over a door allowing air to flow across heat exchanger. ¿Is this correct? Any comments welcome. Thank you. Respectfully, td.