Understanding The Ford C-Max and EPA MPG

C-Max Rear Outside Passenger-side View

Many Ford C-Max Owners Report Lower MPG that 47 City, 47 Highway, 47 Combined

There’s been a multitude of articles discussing owners and journalists getting less than EPA mpg with the Ford C-Max.  I first wrote about this almost one month ago.  The controversy escalated to the mainstream news media when ConsumerReports published their news article on December 7th, “Tests show Ford Fusion, C-Max hybrids don’t live up to 47-mpg claims.”.  It was interesting to me that the Prius C and Prius also fell short of the EPA tests according to ConsumerReports.org.  Thursday, ConsumerReports published a second article, “Why do Ford’s new hybrids ace the EPA fuel economy tests?”  You’d think the two publications were incompatible.  The way these articles were blindly regurgitated by the media was irresponsible.  Last week, Ford C-Max didn’t live up to the “47-mpg claim” and now this week it’s “Ford’s new hybrids ace the EPA fuel economy tests”.  The answer is obvious.  Ford didn’t claim what ConsumerReports “claimed” they did in the first article title.  Ford only said what the mpg on the EPA test was.  That was their claim.  I decided I needed to do a little more research on the topic to add to my earlier discussion.

dyno

The photo above is a dynamometer, often shortened to dyno.  To perform the EPA test, the C-Max is positioned over the dyno.  The dyno is used for repeatability of the laboratory test.  It isn’t the real world.  The EPA doesn’t often perform the test.  The manufacturer does.  The EPA only checks some vehicles.  As I understand it, they checked the C-Max Energi but not the Ford C-Max or Fusion Hybrid.  The EPA doesn’t have the equipment, budget or manpower to test all variations of all vehicles sold in the U.S.

Before going further, please read this quote from an Edmunds article on the EPA MPG test, “… for the most part, the fuel-economy gap exists for a … mundane reason: Real people drive real cars in the real world. There are so many variables that the idea of an absolutely accurate rating of average mpg is laughable. But to new-car buyers, it often feels as if the joke is on them.”

I haven’t been able to locate a detailed description of the EPA tests.  However, the table and associated graphs at the Dept. of Energy site on the EPA MPG test is useful.  There are city, highway, high speed, AC and Cold Temp tests.  The average speed on the high speed test is 48.4 mph.  The highway test is 48.3.  The other three tests have an average speed of just 21.2 mph.  Now, does that sound like the way you drive?

An Edmunds article states calm drivers get up to 35 percent better fuel economy.  The region the vehicle is operated in can affect fuel economy by 12 percent.  The EPA test uses 100 percent gasoline but gasoline contains about 8 percent ethanol which accounts for a 2 percent decrease in fuel economy.  Do you carry passengers?  The EPA tests do not account for people or cargo in the vehicle. A Ford article states each 100 lbs in weight can affect fuel economy by up to 4 percent.

Now, many journalists have suggested Ford rigged the test.  But did they?  There is no evidence for this as far as I’ve been able to tell.  Recall that the ConsumerReports.org MPG tests produce much lower MPG for the Prius C and Prius Liftback.  Here’s a quote from GreenCarReports on the EPA test and hybrids, “During the last decade, the test cycles were so unaggressive that hybrids spent far more time in electric mode on the tests than in the real world, producing wildly high ratings that few owners came anywhere close to.  Public complaints finally forced the EPA to revise its adjustment factors in late 2007, lowering hybrid fuel economy to levels closer to what owners actually achieved.”

I’m not defending Ford.  It may well be that it will be harder to reach the high forty MPG numbers with a C-Max in the real world than with a Prius.  It may be that it is easier to achieve MPG approaching or exceeding fifty with a Prius.  I just think there’s been an overabundance of misleading articles that were poorly researched on the subject.  Daniel Gray of MPGOMatic has been testing the C-Max Hybrid lately.  He’s listed nineteen real-world driving segments with details for the C-Max.  He’s also posted a video for the C-Max.

I decided to append to this article what I’ve read about how to achieve high MPG with the C-Max.  Ford has included the “EcoGuide Lush Vine” and “Brake Coach” to help train drivers to get better mileage.  ”EV+”, which needs to learn GPS data, could take awhile to get GPS data acquired before it improves mileage (it can also be turned off by the user).  ”EcoCruise” (which can be switched off) is also important to get better mileage.  According to John Davis, Ford’s Chief Engineer for the C-Max, once the vehicle is broken in it will achieve 1 to 2 percent better fuel efficiency too.  Now for the suggestions on changing driving behavior.

Do not drive aggressively.  This includes accelerating rapidly from a stop, braking hard at the last possible second, and weaving to change lanes to get around other cars.  Aggressive driving can lower gas mileage by 5 to 33 percent.  Anticipate traffic conditions, curving roads, and traffic lights to minimize braking.  Let up on the gas pedal early to minimize braking.

Slow down to the speed limit.  Speeding can affect fuel economy by 7 to 25 percent.  MPG decreases rapidly at speeds above 60 mph.  Reducing your speed from 65 to 55 mph can improve your fuel economy by 10 to 15 percent.  Reducing your speed from 70 to 55 mph can improve your fuel economy by 25 percent.

Remove excess weight.  Excess weight can reduce mpg by 1-4 percent per 100 pounds.  It affects the C-Max more than large vehicles.

Use cruise control.  Maintaining a constant speed will save gas in most instances.  When driving with cruise control, it is easier to control the maximum speed too.  The C-Max will display the mpg while driving.  To maximize fuel efficiency, set the cruise control speed within the legal speed limit to maximize the mpg on the display.

Use the air conditioner only when needed.  Using the AC reduces fuel economy by up to 15 percent.  In a city, roll down windows and turn the AC off.  Driving above 50 mph with the windows down will increase drag and decrease fuel efficiency more than using the AC.  When using AC, the recirculation setting reduces the air that must be chilled from outside the car.  Using just the fan to circulate unchilled air is more efficient than using the AC.

Start driving when the engine starts.  Modern engines do not need to warm up.  The car warms up faster when the car is running.  However, the engine is most efficient when warm.  Combine trips when possible to avoid infrequent short trips starting with a cold engine.

There are other tips in the C-Max Manual on Page 246.  Now, as Daniel Gray of MPGOMatic.com said in a video, “Get your foot off the gas and let gravity do it’s work.”

[This is not correct.  It was removed on December 29th from the main body of the blog.  “The EPA MPG test isn’t affected by aerodynamics at all.  This is important.  According to Ford, up to 50 percent of the energy required to operate most vehicles is spent overcoming wind resistance.”]

 

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4 thoughts on “Understanding The Ford C-Max and EPA MPG

  1. Good info, pretty much what I’ve been hearing. I expect that Ford did the EPA test procedure correctly and the C-Max really did score 47mpg. I think the core of the problem is that the Ford hybrid tech is very well suited to the EPA test, but real world driving tends to lose some of the advantages of that tech. Or, alternately, you could say that Ford optimized their vehicles for the test more than the real world (either deliberately or accidentally).

    Btw, my understanding is that aerodynamics do count, but they are added as a correction factor after the dyno test is complete. The C-Max has a pretty good coefficient of drag (~0.30), but it’s also moderately tall so it has a good sized frontal area.

    • Mike, thanks for the comment on the dyno. I just found an article in Car and Driver at http://tinyurl.com/7zhjsu3 that states, “After a vehicle is strapped down on a dyno, the staff punches in coefficients that allow the dyno rolls to simulate real-world factors, such as wind and road friction.” That is different than what I understood from the forum link used above. Thanks for the clarification.

  2. I can fully understand many of the epa mileage issues with the information given. But after reading many reviews and testing a Prius V, I am still puzzled. I’ve owned many cars, and driven several Priuses. Typically, I get more than the combined rating, slightly lower highway, always more than city rating. Six Toyotas in a row for me have been no problem to match their epa ratings.

    It’s quite easy to match the spa ratings of a Prius, both of the models I mentioned.

    The Cmax 47/47/47 has, and probably never will be, achieved by anyone. I can see a rating of 43, and you get 40. Very acceptable. I know how to drive hybrids, and I’ve never had to do anything exceptional to get great mileage. The only time this issue generally arises now is with Ford’s hybrids. They clearly have a marketing advantage from the numbers they are allowed to state.

  3. I’ve got about 2600 miles on my C-Max purchased in January. I drive about 40 miles round trip each day in the Los Angeles area. Maybe 30 of those miles are on surface streets and the other 10 miles or so are on the Freeway. My “new” car was caravaned from another dealer, and already had about 80 miles on it when I bought it. The mileage indicator was at 23 MPG at that time.

    I reset the counter when I drove the car off the the lot, and today mileage indicator is at 49.7 MPG. The lifetime summary is over 47MPG.

    So it can be done. I use the pulse and glide technique when driving. Easy starts until the engine kicks in, then quickly get up to about 5mph over the speed limit, then glide. Pulse, glide. Pulse, glide. Easy stops.

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