MPG vs Cruise control report.

[Deadman]

So my wife and I just took my 18 Expedition Max 4x4 tow pack 3.73 gear on a cross country trip. We always ran the mode in SPORT and we both ran 91 Octane fuel. We went from WI to FL and traded off driving numerous times and I reset trip 2 for each of us each fuel load to keep track of our average MPG.

My wife drove with the cruise on the whole time at 79 mph. She had light traffic and rarely kicked it off, but we both hate the Adaptive cruise so that is completely shut off. Every hill the car climbed, I could hear the turbos working. She averaged 18 MPG on the car computer screen for almost every single fuel run.

I ran my fuel runs with NO cruise control at all and I ran it between 80 and 90 mph. I ran it up on the way down hills and then backed off on the way up each hill. I never dropped below 80 and barely heard the turbos on my climbs. (Obviously this was in light traffic, so I wasn't annoying all the cars behind me speeding up and down).
My mpg Average was just over 24 mpg. Thats a 6 MPG difference and I could run 180 miles farther on the same tank of fuel. In my opinion, that's a HUGE difference and clearly shows that the cruise control can't look ahead and anticipate a hill.

Needless to say we could of went from WI to FL on ONE fuel stop! lol.

 

[Flexpedition]

Thanks for sharing. I always knew cruise over-anticipates even the slightest of inclines but had never seen hard numbers.

Just curious, I understand sport mode for city streets and around town, but you selected it for highway cruising - any reason you chose it?

Did you mostly run I65 from Chicago to Nashville, then I24 ~ I75 down to Florida? I've considered 57 from Chicago to avoid Indy and Louisville but never tried it.

 

[Fozzy]

I haven’t driven my Expy enough to know how it reacts on cruise control. I never use it when towing. My F-150 cruise control was way aggressive and would go for the win on hills. And if you used the adaptive once you changed lanes it would go for the hole shot. It was crazy. I would always find my self doing 10 under fallowing a semi truck when I used the adaptive cruise. My wife’s new Aviator will actually change lanes for you if it’s fallowing a slower vehicle. That would be cool. But I have yet to experience it.


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[duneslider]

I too have found when running cruise control the fuel mileage is lower. One thing i don't like is that on down hills it will downshift to maintain whatever the set speed is, which is fine sometimes but that doesn't help mileage.

I don't ever really run in sport mode but based on the trip I took this last weekend, your mileage seems to be the same as I was getting in normal mode. Maybe sport is only affecting the "off the line" characteristics?

I did have a bike rack with 6 bikes on the back with all 6 wheels sticking up over the top of the roof, I feel mileage would have been better without the bike rack too.

 

[2018ExpyPlatinum]

Cruise is a funny thing. At times it's too aggressive. Adaptive is pretty cool, but if you're not paying attention, you can lose 10 mph, then it kicks in to get you back to speed.

When we lived in VA and would go to Pittsburgh, I'd use eco and cruise going out the PA turnpike with moderate traffic, running 72, and average 22 mpg. When we moved to AZ last year, my wife drove the Expy and followed the big yellow rental truck. The rental was governed at 65, would totally go to poop on ANY grade, but she averaged 24, which I thought was pretty darn good. I know she did every other tank regular and super. She used cruise when she could, but it was hard following me.

Thanks for you experiment! I don't think 22-24 is bad for a 6000 pound vehicle, plus, didn't buy it for fuel economy.

 

[AAOO]

Instead of listening for the turbos you can put the turbo gauge on the dash (replace the transmission temp when not towing) to see how much boost you are using.

 

[Artie]

Thanks for the data, very interesting findings. I’m surprised it was that much better at that much higher speeds, I wonder how your wife would fair without cruise at her speeds.

You now have the bonus of hard data supporting your driving style being the superior one over your wife.

 

[Deadman]

Thanks for sharing. I always knew cruise over-anticipates even the slightest of inclines but had never seen hard numbers.

Just curious, I understand sport mode for city streets and around town, but you selected it for highway cruising - any reason you chose it?

Did you mostly run I65 from Chicago to Nashville, then I24 ~ I75 down to Florida? I've considered 57 from Chicago to avoid Indy and Louisville but never tried it.

With the CCD suspension, it handles like garbage in normal mode when its loaded Down. Sport mode stiffens the suspension up and it quite swaying and leaning like crazy. I ordered a rear sway bar for it, so hopefully that takes care of it.

Exactly that route you said. It was good, but we got hun by Chattanooga in construction for a good hour one time.

 

[Deadman]

I haven’t driven my Expy enough to know how it reacts on cruise control. I never use it when towing. My F-150 cruise control was way aggressive and would go for the win on hills. And if you used the adaptive once you changed lanes it would go for the hole shot. It was crazy. I would always find my self doing 10 under fallowing a semi truck when I used the adaptive cruise. My wife’s new Aviator will actually change lanes for you if it’s fallowing a slower vehicle. That would be cool. But I have yet to experience it.


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The cruise is pretty aggressive. Every climb, the turbos were whistling hard! I knew fuel was burning fast from that alone...

 

[Deadman]

I too have found when running cruise control the fuel mileage is lower. One thing i don't like is that on down hills it will downshift to maintain whatever the set speed is, which is fine sometimes but that doesn't help mileage.

I don't ever really run in sport mode but based on the trip I took this last weekend, your mileage seems to be the same as I was getting in normal mode. Maybe sport is only affecting the "off the line" characteristics?

I did have a bike rack with 6 bikes on the back with all 6 wheels sticking up over the top of the roof, I feel mileage would have been better without the bike rack too.

That downshifting is soooo wasteful on the open-road. I used that as coasting free miles where the cruise literally applied brakes or downshifted to slow down and waste energy.

We actually got on the highway and up to speed in NORMAL mode and then immediately clicked to Sport, so it really only affected the suspension as we rarely slowed Down to the speed it would need to downshift.

Oh BTW we had a huge rear hitch carrier loaded down on the back too, so that was not helping us any.