Ecoboost engine MPG drop with Cruise control useage?

[fordmantpw]

I used to have a 2012 Focus HB SEL DCT and I found the same fuel economy situation when using the cruise control.

I also noticed that the car maintained the set speed up hill but also down hill (It felt like it applied a little braking by itself) no matter what kind of slope it was going through. I believe that this may affect the fuel economy a little since the car is not coasting freely. When the cruise control is not active and I did have full control of the car, it went downhill a little faster and coasted freely.

 

Does this sounds logic to you all ???

 

Yep. Our Flex will downshift aggressively when going downhill to maintain speed.

 

silversvt, just a thought. Is there more wind as you reach your destination? Maybe closer to the shore with more headwind?

[fordtion]

In the interest of science, I think it's time for you to do a run at 60mph. You may decide that your time is worth more than what you'd be saving on gas, but at least you'd know. And knowing is half the battle.

60 mph on I-95, stand by to get run over.

[jpd80]

You don't have to be in a hilly area, a slightly undulating road is enough to drive cruise control nuts and use lots more fuel,

especially when the size of the engine is reduced in comparison to the car. When driving with cruise disconnected,

you can anticipate hills and surf over the crest and save fuel down the other side using momentum.

The cruise cannot anticipate stuff like that and tends to be late on changes...

Edited July 31, 2013 by jpd80

[silvrsvt]

You don't have to be in a hilly area, a slightly undulating road is enough to drive cruise control nuts and use lots more fuel,

especially when the size of the engine is reduced in comparison to the car. When driving with cruise disconnected,

you can anticipate hills and surf over the crest and save fuel down the other side using momentum.

The cruise cannot anticipate stuff like that and tends to be late on changes...

 

 

The thing that makes no sense about this is that non-ecoboosted engines doing the same drive deliver equal or better MPG number then their EPA estimates doing the same drive. Driving from Eastern MD to Central NJ is pretty damn flat...I think the highest grade I hit is maybe going onto the Delaware Memorial Bridge :p

 

Once my fuel sending unit is fixed (got CEL and it only shows the car half full, gets fixed next week) I'll do more driving without using the cruise control around town and being careful with the throttle.

 

Just as an example, I was able to pull 21 MPG out of my 120K Mustang GT around town the past couple days while the SHO was at the dealership...without even trying and using the cruise control on it.

 

I was able to get 25 MPG once...not sure what heck I was doing then, maybe I have to drive it like an old man to get those types of # again...which is no fun

[Pioneer]

Try driving 60-65...I bet you'll get several MPG better.

I just got back from the Baltimore/Washington D.C. area. If he were to drive that slow, he get run over by 18 wheelers.

 

Traffic is nuts out there.

[brucelinc]

Unless we are talking really stiff headwinds or very hilly areas, I don't see why cruise control would make any difference when just cruising down the Interstate at 75-80 MPH.

 

Silvrsvt, you and I have the same engine. You have a 3.16 gear and mine is a 2.77 so that would make some difference in highway mileage. Having said that, I would expect you to meet or beat the EPA highway rating. I have had mine 4 years and driven it in about every condition possible. Yes, using the boost will use fuel. In mixed freeway/city, 20-21 is about all you can expect. However, open highway cruising over a fairly long distance is where you should see the larger numbers.

 

Before getting the tune, I would get 26-27 on roundtrips between Minneapolis and Des Moines on a regular basis driving 75-80. A headwind would knock that down some and a tail wind would help. After the tune, I have picked up about 1.5 MPG overall. I suggest you check the RPM when you are cruising. It should be rock steady unless you are going up a steep hill. If your torque converter is not locking up (or unlocking too easily) it would have an effect on your highway mileage.

 

Based on my experience and that of dozens of other SHO/MKS owners that I converse with, you are not getting the highway mileage that you should.

Edited July 31, 2013 by brucelinc

[fordmantpw]

Once my fuel sending unit is fixed (got CEL and it only shows the car half full, gets fixed next week)

 

We had the exact same problem on our Flex. Only, we didn't get a CEL, and ours was delivered with it faulty.

[fordmantpw]

I just got back from the Baltimore/Washington D.C. area. If he were to drive that slow, he get run over by 18 wheelers.

 

Traffic is nuts out there.

 

I didn't necessarily imply that it would be safe.

 

I take the traffic (or lack of) in my neck of the woods for granted. Traffic for me means I have to actually stop at the stop sign.

[RichardJensen]

The thing that makes no sense about this is that non-ecoboosted engines doing the same drive deliver equal or better MPG number then their EPA estimates doing the same drive

 

I think that's because of the Jekyll/Hyde character of the EB engine. You get too far into the boost and Pfft. Bye-bye mileage.

[fordmantpw]

I think that's because of the Jekyll/Hyde character of the EB engine. You get too far into the boost and Pfft. Bye-bye mileage.

 

Yep, and it's not just EB's, it's all turbo engines. My diesel is the same way.

[brucelinc]

Yep, and it's not just EB's, it's all turbo engines. My diesel is the same way.

Absolutely, when in the boost, you will use fuel. However, when cruising 75-80 on level ground, you will not be in the boost with a SHO and mileage will be similar to a NA 3.5 with the same gearing.

[fordmantpw]

However, when cruising 75-80 on level ground, you will not be in the boost with a SHO.

 

I would beg to differ. I bet there is considerable boost at 75-80 in the SHO. Wind resistance is a killer at that speed.

Edited July 31, 2013 by fordmantpw

[brucelinc]

I would beg to differ. I bet there is considerable boost at 75-80 in the SHO. Wind resistance is a killer at that speed.

A boost gauge will show vacuum at that speed until acceleration is called for. Then it will show boost.

[fordmantpw]

A boost gauge will show vacuum at that speed until acceleration is called for. Then it will show boost.

 

Hmmm, at 75-80? I'd have to see that to believe it.

 

The boost gauge in my SD will run around 10 PSI at that speed. Granted, I've got a lot more wind resistance, and it is a diesel, but I doubt it's negative boost at 75+ in a SHO.

[brucelinc]

OK, I am not trying to be argumentative. I am only trying to point out that the original poster is not getting the highway mileage that he should - or the mileage that others with SHOs are reporting under the ideal conditions that he seemed to be describing. Again, assuming reasonably calm winds and level roads and steady cruising at 75-80, the mileage will be similar to a NA 3.5. I have both - in an MKS ecoboost and a Taurus SEL - and have driven the same routes with both many times.

 

Many of us who have experience with the 3.5 ecoboost and are active in the SHO/MKS forums and clubs have installed boost gauges so I am not guessing or speculating about boost levels, either. By the way, absolute max boost on a stock SHO will run up to 12 PSI but you need to be WOT and higher RPM too see that. Many report closer to 9 or 10 PSI max. Accelerating hard from 2000 RPM (around 80 MPH) will generate less than that unless you force a downshift to bring up the RPM. Again, the OP has a 3.16 gear and I have a 2.77 so that will make some difference in RPM levels and highway mileage.

[silvrsvt]

As an FYI, the parents old car, a '08 Sable with the 3.5L and AWD was getting about 23 MPG I believe doing the same trip.

[fordmantpw]

OK, I am not trying to be argumentative. I am only trying to point out that the original poster is not getting the highway mileage that he should - or the mileage that others with SHOs are reporting under the ideal conditions that he seemed to be describing. Again, assuming reasonably calm winds and level roads and steady cruising at 75-80, the mileage will be similar to a NA 3.5. I have both - in an MKS ecoboost and a Taurus SEL - and have driven the same routes with both many times.

 

Many of us who have experience with the 3.5 ecoboost and are active in the SHO/MKS forums and clubs have installed boost gauges so I am not guessing or speculating about boost levels, either. By the way, absolute max boost on a stock SHO will run up to 12 PSI but you need to be WOT and higher RPM too see that. Many report closer to 9 or 10 PSI max. Accelerating hard from 2000 RPM (around 80 MPH) will generate less than that unless you force a downshift to bring up the RPM. Again, the OP has a 3.16 gear and I have a 2.77 so that will make some difference in RPM levels and highway mileage.

 

I'm not trying to be argumentative, just trying to learn something.

[brucelinc]

I am beginning to wonder if I35 between Minneapolis and Des Moines in downhill both ways! I almost always meet or exceed the EPA highway numbers when I make that trip - whether in my personal vehicles for pleasure or in a rental car when I travel for business - unless there is a headwind.

My MKS ecoboost has actually beaten it's rating by the highest amount - although it will also come WAAAY short around town if I drive it aggressively. As they say, your mileage will vary....

[Biker16]

The interesting thing with Cruise control and modern cars is that my 2000 would always get better mileage on cruise than without cruise. becuase the computer is more o consistant in throttle applications than the Driver,

 

The opposite being true today says alot about the importance of software.

 

common sense would tell you that if cruise is set there would be less variability to engine demand and load factors, than would be expected during normal use. If you have been foloowing the Ford HEV "issues" ford is programing out some margins and fine-tuning them to better reflect real world usage, ( it is different programing an power pack to work Equally well in -30 degree Weather and +120 weather than in normal driving conditions) they built margins into the system to accommodate extremes but may not have optimized it for normal conditions.

 

fast forward to what would be a better operating environment with cruise control, where the ECU should be able to "let its hair down" and shrink those margins of performance, I.E. higher engine temps, more favorable Cam profiles, more use of Quasi-Atkinson cycle, more use of EGR, Grille shutters, shift points etc. because the ECU doesn't need the extra margins of perforace needed when crusie is off, no need to be prepared for a sudden WOT event, because cruise is on.

 

It may also be the ECU after learning driver habits, cannot adjust to ECU driving habits.

 

:shrug:

[Edstock]

It may also be the ECU after learning driver habits, cannot adjust to ECU driving habits.

 

:shrug:

 

Ya gotta love it.

[transitman]

Since I purchased my 2.0L Escape, I have taken two long trips where I used the cruise control for a majority of the distance. The first trip was from Wilmar, MN to Krotz Springs, LA by way of US 71, which is primarily a 2 lane highway with 4 lane by passes and short distances on freeways through urban areas. The second trip was from Minneapolis to Sun City, AZ by way of I-35, I-40 and I-17. I saw much better mpg's on the 2 lane trip than on the interstate trip. Both had stretches of hilly and flat travel, but it was all about speed and the timing of when to cancel cruise and use your foot, and when to resume the set speed and use cruise. I found the sweet spot to maximize mpg's to be 60-63 mph. Beyond 65 mph, the mpg's begin to drop and will be below the EPA estimates and depending on wind and road conditions, they can be well below estimates. At the 70-75 mph range, I have found it difficult to get over 25-28 mpg on flat roads and with no wind or a tail wind. The best mpg's I have achieved in my Escape was 38 mpg, driving across Iowa on US 71, low rolling hills, 62 mph, autumn temps little to no traffic. When I saw a larger hill in the distance, I would cancel the cruise, slowly gain speed, climb the hill without down shifting, at the crest let off the accelerator, coast about 1/3rd of the way down the other side and resume the cruise when the speed was at or near the set speed. On the AZ trip, because the speeds were 70-75 mph, the best I got was 32-34 mpg on flat terrain in W Texas and N New Mexico, and that was with a slight tailwind. At interstate speeds, with varying conditions, the average was more in the 26 mpg range. I don't know about margins of performance, ECU adjustments or software programming, all I know is you have to learn how to use the cruise for maximum economy. Don't let the transmission downshift, ever, use your foot to anticipate when speed is needed to climb and don't have the cruise on when you are descending hills, it is going to keep it at a constant speed and will seek a lower gear to maintain that speed. As stated earlier, in the majority of conditions, cruise control is a convenience, not a way to maximize mileage. Maximizing economy, even when using cruise control, takes a little work, foresight, anticipation and experience. You need to see the big picture and drive well ahead of the front end of the car. Anticipate when more speed or power is going to be needed and don't use the cruise to get to speed, gradually climb and then hit resume. Since I usually travel solo, I make a kind of game out of it and feel good when I see the average mpg's readout increase, even a few tenths.

Edited August 4, 2013 by transitman

[silvrsvt]

Well just a follow up with the car....I had to get a sending unit in the fuel tank fixed in it so I couldn't report MPGs for a few weeks. Anyways, this was first tank of gas where I could report MPG with the car working properly. I drove the entire week to work (about 15 miles highway with several stop lights) and didn't use the cruise control at all and I was reporting about 22 or so MPGs, till I got on the gas a bit and knocked it down a bit to the high 20s or so.

 

I drove out to PA yesterday (about 100 miles one way) I didn't use the cruise at all. This trip was different from my normal PA trip since I couldn't do 75 the whole time due to being on 2 lane back roads for the most part...I was able to increase my MPGs back up into the 22 MPG range on my way home (didn't reset the MPG counter) from my normal ride to work during the week....so I'm really curious to see how I do at a steady state of 75 or so on a major highway not using the cruise, since my MPG's are pretty decent for not being on a highway. I'm "babying" the car a bit...keep my RPMs around 2.5-4K or less when accelerating. I can live with 22 MPG for my "around town" MPG vs 20-21 with the Mustang I have.

[RichardJensen]

4k or less when accelerating is 'babying it'?

 

Holy crap dude! You would not have fun riding shotgun with me.

[silvrsvt]

4k or less when accelerating is 'babying it'?

 

Holy crap dude! You would not have fun riding shotgun with me.

 

 

LOL for the most part its 2K rpms....the car tops out around 6K RPMs so thats Alot LOL

[silvrsvt]

Well got in an unexpected drive to Jersey yesterday, a buddy of mine's mom passed away unexpectedly from complications from a brain tumor.

 

Anyways, I finally got in some more testing with the deal with MPGs with the Ecoboost...I didn't use cruise the whole trip up there. I started off at 18.5 or so MPG going by the computer (just filled it the morning before and only traveled 3 times to work and home at around 15 miles one way) and was moderate with my throttle usage (no WOT and only reving to say about 4-4.5K RPMs before the car shifted) and kept my speed around 75-80MPH and by the time I got to my detestation in Jersey, I was reading about 23 MPG...and it kept rising as I went till I hit a shit load of traffic getting back between rush hour, accidents and traffic....a normal 2 hour drive turned into a 3.5 hour drive and my MPG's lowered down to 22.5MPG or so. I'm almost due a fuel up, which I'll be doing tomorrow, and I'll be doing a bunch more driving between Thursday and Friday...have to goto BWI to pick a friend up then head up to CT on Friday morning. Traffic shouldn't be an issue since it will be after rush hour, so I'm curious as to how good my MPG will be. I might try running cruise on the way home from CT to see if how much of a difference it makes.