I believe you are referring to the problem of "coking" which I believe is caused by thermal shock (fast cool-down) and has been addressed by Ford utilizing water-cooled small turbos which cool more slowly because of the heated water, at least that's the idea, eliminating the need for the extended shut-down time. I understand they proved it during their extensive testing during the development of the TT 3.5 we have now. They did claim some pretty high mileage results (160,000+) but did not include any part replacement due to failure or wear in their consumer videos of the testing procedure other than tearing down the engine to a bare block and looking at internal wear. It would be interesting to know which parts failed in those tests because they leave one with the impression that nothing failed but how about the bolt-on stuff like turbos, starter, alternator, fuel pump, water pump, injectors, etc? They drove the truck pretty hard, like 24 hrs wide-open pulling 9000 lbs, Drag racing up a long hill again pulling 9000 lbs, pulling logs twice the weight of the truck, racing in Baja...I would expect driving it that hard would cause some failures along the way.

 

I know it's a late reply, but the key item they are missing is the amount of time they spend accelerating. When specifying buses at work, we have acceleration curves from certain duty cycles that we use to specify bus performance. There's no knowing of how fast they accelerated or how slow. What's "Real World" to a hot rodder isn't "Real World" to a more conservative driver. In personal experiments with my Sky Redline, I found that I got better fuel mileage by either staying out of the boost completely (very hard to do) or when accelerating under boost, accelerate more briskly than not, so you minimize your time in boost. Those were my personal findings for best fuel mileage (that car was rated at something like 20/29, I averaged about 27 mpg combined, or 33 mpg on a long freeway trip).

 

... I found that I got better fuel mileage by either staying out of the boost completely (very hard to do) or when accelerating under boost, accelerate more briskly than not, so you minimize your time in boost. Those were my personal findings for best fuel mileage (that car was rated at something like 20/29, I averaged about 27 mpg combined, or 33 mpg on a long freeway trip).[/quote]


You bring up an important point when talking about acceleration. I've done a lot of experimenting with mine and found that my mileage is actually worse if I accelerate slowly from a stop...if I accelerate moderately and get into sixth quicker the mileage is a little better...not a ton better but still better. It's also worse if you put your foot in it but I think we all know that. It's really not so important until gas gets near $4 but if I practice, I develop good habits and I get better mileage no matter what the cost. Let's face, it's a fun truck to drive...good holeshot and good acceleration...faster than any stock Ford truck I've ever owned. Like Tim, I played with it early on but I'm much more sedate with it now. I hate paying for more gas than I need to pay for.

 

I absolutely agree that the rate of acceleration is a big factor and hard to match in testing different vehicles. Unlikely CR uses a G meter to standardize acceleration. Certainly, I believe that when driving a faster vehicle, most people will accelerate faster. My wife's old '92 Grand Prix was not really fast, but it had a hair trigger gas pedal that put about 80% throttle in the first 20% of throttle movement. I'm sure that both of us ran the car harder because of the gas pedal calibration and the cool sound of the exhaust system (a nice burble from the old 3.1 V6).

Again, I am totally with you on the limitations of testing on a prescribed course even if speed limits are observed. And like you, I have discovered that I can massively improve mileage by driving like a little old lady, keeping at 60-65 mph on the freeway, but driving like this bugs me so much that I resign myself to using more gas. The only turbo car I ever had was an '86 Dodge Lancer and I LOVED to hear the turbo whine so I got into the turbo a lot... About 20-22 mpg on premium, no overdrive, only 146 horsepower in a 2800 lb car. We have come a long way.

I really wonder out loud how much gas an EB would use compared to the 3.7 NA engine and the 5.0 at a constant power level, say 100 or 150 horsepower... And likewise I would wonder this about other vehicles as well.

By the way, early in the thread someone mentioned that CR did not test Japanese turbo cars like the Subaru WRX, but that is a specific performance model, whereas the cars in the test are generally more like "regular people cars" which use turbos in regular applications. For example, almost every Escape out there is gonna have one of the EB engines and these are meant to be sold to the general public. The NA 2.5 is only available in the 2WD base model, I think.

George

 

George, yet another excellent well thought out post from you sir.

However, IMHO, while the WRX is a purpose built street rodder, the F-150 Ecoboost is a purpose built mule.

The 3.5L TT in the F-150 is not a car engine, it's architecture is different from it's cousins in the sedans. It creates more more HP and substantially more TQ than that found in the Taurus, etc. Then again, the trannys in the sedans are rated for 550 ft'lb of TQ while the 6R80 is rated at 800 ft/lb. The truck version would destroy a transmission in the sedans.

CR IS NOT making that distinction as they likely don't know or just don't care to delve into this level of detail.

The 3.5LTT uses the same bore size as the 5.0L while it's stroke is slightly shorter and the engine weighs nearly as much as the 6.2L V-8. This things is a hoss pure and simple.

CR is pandering to people who don't do true vehicle research. I do trust their reporting efforts on used cars as this is all historical data. I don't believe a word they say about new cars.

 

My wife's 2013 2.0 Ecoboost escape Gets 25 on the highway at 65MPH. It's rated at 30. That's pretty far off. EPA needs to recalculate their data for the small turbos (if they actually did test these) In comparison, My 2013 F150 5.0 gets 22 at 65MPH, with a 21 rating. That's 9 MPG spread in ratings, with the 2.0 getting only 3 mpg better than the 5.0. Somethings off.......

 

Hi Tim:
I am in no way trying to get the "last word" here, but Subaru sold 13,000 WRX's in 2011 and the same in 2012. Ford sold 645,000 F series trucks in 2012 and I read that the Ecoboost made it into 42% of F150's. Given that F series sales include the SD, I will guess that is still over 200,000 F150 EB's on the road in 2012. I think Subaru as a company sells only 300,000 vehicles a year.

So including the F150 in CR's analysis (and I do have my doubts as to their testing methods as I said), does make more sense because I would definitely define it as a mass market vehicle. The EB in the F150--as high tech as it is--is not a niche vehicle, the WRX is. And as such, writing about the F150 is gonna reach many more people who read CR. Likewise, I am guessing that 90% or more of new Escapes will have one of the EB engines in them. Ford is going big with turbos; the Japanese are not there, at least yet. Part of this is that Ford is gonna have a harder time meeting CAFE averages than Subaru and Honda...

Thank you for the good discussion,
George

 

I don't think anyone is gonna be redoing EPA tests if their results are high. From everything I remember the 3.0 Duratec in the old Escape would get about 25 mpg on the road, and it is rare for any small SUV to even hit the high 20 mpg range on the freeway. Is her engine broken in?

My wife drives around 80 on the freeway and is much heavier into the gas and brakes than I am...you sure your bride is telling the truth?

George

 

[quote=LSchicago2;12817776]My wife's 2013 2.0 Ecoboost escape Gets 25 on the highway at 65MPH. It's rated at 30. That's pretty far off. EPA needs to recalculate their data for the small turbos (if they actually did test these) In comparison, My 2013 F150 5.0 gets 22 at 65MPH, with a 21 rating. That's 9 MPG spread in ratings, with the 2.0 getting only 3 mpg better than the 5.0. Somethings off.......

Interesting you should bring up the Escape. Makes me wonder how many miles are on it. My wife just got herself a 2.0 Escape AWD two weeks ago rated at 21/28. She is now on her third tank of gas and getting 20 mpg in mixed driving and we live in Minnesota so the vehicle gets a fair amount of idle time which skews the mileage. The first tank showed about 15 and the second 18.5 so it's getting better as the engine begins to break in. When I first got my F-150 EB in 2011, the first few tanks were not so good but the Ford folks told me not to expect the best mileage until it gets over 10M miles...it takes that long to break it in...and they were about right on and I had to learn to drive it for best mileage. I'm right where the mileage figures say it will be as long as I keep my foot out of it but even when I'm "playing" with it, I still get in the 14's. Maybe the Escape needs that long as well. I also know my wife does not "drive for mileage". She's got a pretty heavy foot, so I wouldn't expect her to get the best mileage.

 

In addition to break-in issues, remember that we are all on winter formulation gasoline, which stinks for mileage. Last couple tanks in my E150 were a bit over 14 mpg, in driving that I would expect to get me 16ish in the summer. And I am running it longer for warmups to soften up the ice on the windows.

George

 

Good point on the lousy gas, George. I noticed about a 1-2 mpg drop last October when MN switched to the "winter formulation". I'm running about 14.5 to just over 15 on the average in mixed driving right now. Mine's in the garage but it still gets a lot more idle time than during the summer. Jim