Very disapointing fuel economy from recent roadtrip...

B

buyingconstant7

Member
:
2014 CX-5 GS AWD
Was going to take my 2013 Jetta TDI and its 50+mpg mile eating awesomeness from Calgary, AB, to Winnipeg, MB. But I had to stay home and needed my car so mom went on her own in her 2014 CX-5. She stuck to around 115km/h(70mph) the whole way there and went 80mph the way back. It wasn't windy, weather was about 20c, A/C was off, etc. She usually gets around 30mpg in her daily commute, doing about 100km a day. Here was her fuel economy numbers along the way to and from Winnipeg(US units):
Way there(speeds of 70mph):
1st:28.4mpg
2nd: 28.8mpg
On the way back(speeds of 80mph)
1st: 21mpg
2nd: 23mpg
3rd 24mpg
Clearly, the 2.5 was working it's ass off to go 80mph...for what? Why on earth would this thing get 21mpg on the highway, doing relatively reasonable speeds?!? She was super disapointed and raised the point that she traded her $40,000 Tiguan in, for something slightly bigger, slightly cheaper to run and better on fuel, but from these numbers, the Tiguan would've matched them EASILY. Can someone chime in on why the numbers are downright awful at higher speeds?
 
I did LA to San Francisco round trip. Overall did about 30 mpg @ 80 mph. I have 2016 GT.

Sent from my iPhone using Tapatalk
 
Based on the numbers you provided you averaged about 25mpg for the trip, or your mother did. A quick google search shows that Calgary has an elevation of roughly 3500 feet while Winnipeg has an elevation of about 750 feet. Heading east you most likely have a bit of a tail wind even if it's not "windy" so to speak and you are going down hill. Coming back, heading west you are facing a bit of a head wind from the jet stream and what not, even if you can't perceive it, It's why weather moves from west to east. You're also climbing back up that elevation and you stated that the speeds are higher. Eventually you get to a speed with a car where you have to be using more fuel and more of the engines power to over come wind resistance. Although the CX-5 is pretty decently designed for low drag there still is drag and I imagine that the extra 10mph coupled with the heading into the wind and going up in elevation is why you're seeing the drop in Mpg on the return trip.
 
buyingconstant7 said:
Was going to take my 2013 Jetta TDI and its 50+mpg mile eating awesomeness from Calgary, AB, to Winnipeg, MB. But I had to stay home and needed my car so mom went on her own in her 2014 CX-5. She stuck to around 115km/h(70mph) the whole way there and went 80mph the way back. It wasn't windy, weather was about 20c, A/C was off, etc. She usually gets around 30mpg in her daily commute, doing about 100km a day. Here was her fuel economy numbers along the way to and from Winnipeg(US units):
Way there(speeds of 70mph):
1st:28.4mpg
2nd: 28.8mpg
On the way back(speeds of 80mph)
1st: 21mpg
2nd: 23mpg
3rd 24mpg
Clearly, the 2.5 was working it's ass off to go 80mph...for what? Why on earth would this thing get 21mpg on the highway, doing relatively reasonable speeds?!? She was super disapointed and raised the point that she traded her $40,000 Tiguan in, for something slightly bigger, slightly cheaper to run and better on fuel, but from these numbers, the Tiguan would've matched them EASILY. Can someone chime in on why the numbers are downright awful at higher speeds?
Click to expand...

Yep. Same thing mine does.
 
Ride92 said:
Based on the numbers you provided you averaged about 25mpg for the trip, or your mother did. A quick google search shows that Calgary has an elevation of roughly 3500 feet while Winnipeg has an elevation of about 750 feet. Heading east you most likely have a bit of a tail wind even if it's not "windy" so to speak and you are going down hill. Coming back, heading west you are facing a bit of a head wind from the jet stream and what not, even if you can't perceive it, It's why weather moves from west to east. You're also climbing back up that elevation and you stated that the speeds are higher. Eventually you get to a speed with a car where you have to be using more fuel and more of the engines power to over come wind resistance. Although the CX-5 is pretty decently designed for low drag there still is drag and I imagine that the extra 10mph coupled with the heading into the wind and going up in elevation is why you're seeing the drop in Mpg on the return trip.
Click to expand...

I agree and would like to expand on the drag portion of the situation.

The force required to overcome drag is: 1/2 X drag coefficient X air density X drag area X speed[SUP]2[/SUP]

The important thing in that equation is that it is speed squared. Going from 70 to 80 is a 14.3 % increase in speed but it needs a 30.6 % increase in force to overcome the additional drag.

A couple of weeks ago I had to run an errand to a town 15 miles south of me. 20 mph winds that day, straight out of the south. Two lane highway, 55 mph speed limit, I did 55-60. My mileage going into the wind, 27.4 mpg. Return trip, 30 minutes later, same conditions and speed, 37.4 mpg. The CX-5's mpg is definitely drag sensitive.
 
brillo54 said:
I agree and would like to expand on the drag portion of the situation.

The force required to overcome drag is: 1/2 X drag coefficient X air density X drag area X speed[SUP]2[/SUP]

The important thing in that equation is that it is speed squared. Going from 70 to 80 is a 14.3 % increase in speed but it needs a 30.6 % increase in force to overcome the additional drag.

A couple of weeks ago I had to run an errand to a town 15 miles south of me. 20 mph winds that day, straight out of the south. Two lane highway, 55 mph speed limit, I did 55-60. My mileage going into the wind, 27.4 mpg. Return trip, 30 minutes later, same conditions and speed, 37.4 mpg. The CX-5's mpg is definitely drag sensitive.
Click to expand...

Can't argue with science.

Going above 70mph will hurt MPG, no way around it. The CX5 while aerodynamic is still a lifted CUV. It's not a high-end low to the ground sports car. Even a Corvette will lose MPG once above 75MPH. The sweet spot for the C6 was around 70-75MPH. After that the MPG started to drop. Maybe the newer C7 with the 8 speed trans might be good to 80MPH.

As I stated, I am being 100% honest and factual. On my 2016 GT with AWD, 19" OEM rims, OEM roof rack, OEM mudflaps, I get 29-31MPG on the highway as long as I keep the speeds 65-70MPH.

Another thing to make sure is that the windows are CLOSED when on the highway. If open, they produce a lot of drag. Also air your tires to 40psi COLD. Ride will be firmer but MPG will increase.
 
Lbear said:
Can't argue with science.

Going above 70mph will hurt MPG, no way around it. The CX5 while aerodynamic is still a lifted CUV. It's not a high-end low to the ground sports car. Even a Corvette will lose MPG once above 75MPH. The sweet spot for the C6 was around 70-75MPH. After that the MPG started to drop. Maybe the newer C7 with the 8 speed trans might be good to 80MPH.

As I stated, I am being 100% honest and factual. On my 2016 GT with AWD, 19" OEM rims, OEM roof rack, OEM mudflaps, I get 29-31MPG on the highway as long as I keep the speeds 65-70MPH.

Another thing to make sure is that the windows are CLOSED when on the highway. If open, they produce a lot of drag. Also air your tires to 40psi COLD. Ride will be firmer but MPG will increase.
Click to expand...

+1
I keep my tires at 38psi cold and get around the same highway as yourself. I will be checking more now that I believe summer blend fuel is in full swing.
 
I promise my Jeep had a lot more drag than this CX-5, and going above 70, it STILL got 17-19mpg (rated at 18) on long road trips.
 
Unobtanium said:
I promise my Jeep had a lot more drag than this CX-5, and going above 70, it STILL got 17-19mpg (rated at 18) on long road trips.
Click to expand...

Could be the more powerful engine to weight ratio? My old mustang gt 08 got better gas mileage than my buddy's 10 v6 mustang. His was newer, probably a little lighter, and not a v8. But I think having the extra power of the v8, made it easier to keep the car cruising and working less whereas his v6 had to work a little harder to keep that car rolling. This isn't fact but was just my hypothesis. Perhaps similar to why your Jeep did well.
 
The significant decrease in mileage has to do with the fact there is an exponential relationship between speed and drag, rather than linear.

Here is a simple article explaining it.

http://www.mpgforspeed.com
 
buyingconstant7 said:
Clearly, the 2.5 was working it's ass off to go 80mph...for what? Why on earth would this thing get 21mpg on the highway, doing relatively reasonable speeds?!? Can someone chime in on why the numbers are downright awful at higher speeds?
Click to expand...

I have more than once had the experience (in a 2013) of flooring along the on ramp on to the main highway and then settling on a cruise speed of 100 kph. After a bit of time at highway speed and thinking that the engine sounded a little over-revved I have pushed the stick over to manual to discover that the transmission is holding 5th gear. I manually force it into 6th and all is fine. This could possibly be it. Just sayin'...

Brian
 
It's drag. Plain and simple. Caused by frontal area and shape. If you want to get better than 28 MPG on the highway, keep your speed below 110 kph/68 mph. Or get a vehicle with smaller frontal area.
 
buyingconstant7 said:
... Clearly, the 2.5 was working it's ass off to go 80mph...for what? Why on earth would this thing get 21mpg on the highway, doing relatively reasonable speeds?!? She was super disapointed and raised the point that she traded her $40,000 Tiguan in, for something slightly bigger, slightly cheaper to run and better on fuel, but from these numbers, the Tiguan would've matched them EASILY. Can someone chime in on why the numbers are downright awful at higher speeds?
Click to expand...
I had exactly the same feeling of OP's mom, as the gas mileage was fine during daily city driving, and we're expecting much better MPGs for the long highway trip. But the outcome from the trip was very disappointing, not much better or even worse than what we can get from daily city driving!

Forget about all the science you guys are thrown in. They are irrelevant to our complaints because we're comparing different compact CUVs under similar condition and environment on the highway. Also the compared vehicles are a lot easier to meet EPA's highway estimates if we really tried. OP's mom made 1,700-mile trip and was getting 25 mpg. OP said his mom's 2014 CX-5 AWD, comparing to her previous VW Tiguan, a compact CUV, had unsatisfactory gas mileage during her recent long trip. Unobtanium made a long Texas trip and was getting 24~25 mpg. Comparing to his previous Jeep, gas mileage is unsatisfactory. We made 800-mile trip to Houston and Austin and was getting 26~27 mpg. Comparing to our Honda CR-V AWD, we also experienced unsatisfactory gas mileage during this trip! I could never see anything close to EPA's 30 mpg highway mark no matter how hard I'd tried.

People who have outstanding gas mileage (30+ mpg) on 2.5L CX-5 are either have FWD or their 2.5L SA-G's somehow been manufactured more efficient than others. They also failed to mention when we're complaining about the MPG on CX-5, we're comparing to other vehicles doing the trip in similar conditions.
 
did a trip to Indiana and Chicago, it was also below EPA rating.

One thing worth mentioning is, I have better MPG if I don't use cruise control. Our previous cars (HONDA/Acura)has better MPG if we use cruise control (weird)!

I kept using the sport mode, this CUV is fun!
Damn!
 
Lbear said:
Can't argue with science.

Going above 70mph will hurt MPG, no way around it. The CX5 while aerodynamic is still a lifted CUV. It's not a high-end low to the ground sports car. Even a Corvette will lose MPG once above 75MPH. The sweet spot for the C6 was around 70-75MPH. After that the MPG started to drop. Maybe the newer C7 with the 8 speed trans might be good to 80MPH.

As I stated, I am being 100% honest and factual. On my 2016 GT with AWD, 19" OEM rims, OEM roof rack, OEM mudflaps, I get 29-31MPG on the highway as long as I keep the speeds 65-70MPH.

Another thing to make sure is that the windows are CLOSED when on the highway. If open, they produce a lot of drag. Also air your tires to 40psi COLD. Ride will be firmer but MPG will increase.
Click to expand...


Bingo!. My experience as well. Keep it at 70 or below, and the economy is great. (I haven't check the tire pressure since I bought it eight months ago, so I'm not trying any special tricks.) I live at sea level and have plenty of hills to traverse. Drive smooth, don't speed more than you must, and mileage is quite good. As an added bonus, the Mazda-calculated MPG is typically 0.2 to 0.5 MPG lower than hand calculated numbers.

The EPA test only exceeds 80 mph very briefly, in fact, test speeds at 70 mph are relatively short duration. I'm thrilled with 29-30 MPG on my commute where I'm going up and down hills and travelling on the interstate at 70-73 mph.
 
Last edited:
Ride92 said:
Based on the numbers you provided you averaged about 25mpg for the trip, or your mother did. A quick google search shows that Calgary has an elevation of roughly 3500 feet while Winnipeg has an elevation of about 750 feet. Heading east you most likely have a bit of a tail wind even if it's not "windy" so to speak and you are going down hill. Coming back, heading west you are facing a bit of a head wind from the jet stream and what not, even if you can't perceive it, It's why weather moves from west to east. You're also climbing back up that elevation and you stated that the speeds are higher. Eventually you get to a speed with a car where you have to be using more fuel and more of the engines power to over come wind resistance. Although the CX-5 is pretty decently designed for low drag there still is drag and I imagine that the extra 10mph coupled with the heading into the wind and going up in elevation is why you're seeing the drop in Mpg on the return trip.
Click to expand...

This was my first guess too. I know for me when I head to Reno from the bay area I see a drastic difference on the way back vs going there.
 
How did OP calculate mileage? Did he zero the onboard system out once on the highway or sometime before? Or use the odometer and a gas pump's reading?

I have gotten 34 on the AUS->DFW trip in my 2.5. Kept it around 70 mph. Zero out the onboard once you're on the highway. Going to 80 greatly reduces due to drag, although I still usually get in ~28 range.
 
Last edited:
yrwei52 said:
I had exactly the same feeling of OP's mom, as the gas mileage was fine during daily city driving, and we're expecting much better MPGs for the long highway trip. But the outcome from the trip was very disappointing, not much better or even worse than what we can get from daily city driving!

Forget about all the science you guys are thrown in. They are irrelevant to our complaints because we're comparing different compact CUVs under similar condition and environment on the highway. Also the compared vehicles are a lot easier to meet EPA's highway estimates if we really tried. OP's mom made 1,700-mile trip and was getting 25 mpg. OP said his mom's 2014 CX-5 AWD, comparing to her previous VW Tiguan, a compact CUV, had unsatisfactory gas mileage during her recent long trip. Unobtanium made a long Texas trip and was getting 24~25 mpg. Comparing to his previous Jeep, gas mileage is unsatisfactory. We made 800-mile trip to Houston and Austin and was getting 26~27 mpg. Comparing to our Honda CR-V AWD, we also experienced unsatisfactory gas mileage during this trip! I could never see anything close to EPA's 30 mpg highway mark no matter how hard I'd tried.

People who have outstanding gas mileage (30+ mpg) on 2.5L CX-5 are either have FWD or their 2.5L SA-G's somehow been manufactured more efficient than others. They also failed to mention when we're complaining about the MPG on CX-5, we're comparing to other vehicles doing the trip in similar conditions.
Click to expand...

I suspect OP didn't zero out on the highway or take into account that the drag coefficient on CX-5 (and any vehicle of its stance) is worse than that of a Jetta.
 
I just got back from a 40 mile round trip. I kept speeds below 60MPH. This is the 2.5L GT, AWD, Roof Rails, OEM Mud Flaps

 
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