Damn good gas mileage!

CivicXI

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I do a lot of high way driving and I've come to the conclusion that there's some dark magic happening in the Honda 1.5T engine in my hatchback. Either that or it's a combination of good design, lightness, and aerodynamics.

We all know that the car gets great gas mileage. A few of us also know that aerodynamic drag increases as a square root. So you'd expect gas mileage to drop insanely as speed increases but I've found that it's almost linear, which is crazy.

At 65mph, I get 42 mpg.

Looking at it proportionally, I would get:

55mph = 49.6mpg
75mph = 36.4mpg
85mph = 32.1mpg
95mph = 28.7mpg
105mph = 26mpg

Here's what i've measured, each on the same stretches of thruway in nearly the same conditions at night on stretches of about 10 minutes.

55mph = 51mpg
75mph = 38mpg
85mph = 32mpg
95mph = 27mpg
105mph = 23mpg

It stays insanely and unreasonably linear. When winter really sets in and temperatures are below 30, I expect about about a 15-20% drop (purely due to air density).

Is anyone else seeing this pattern?
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turbo lover

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Most vehicles are close to linear if you plot MPG vs MPH, even heavy and un-aerodynamic vehicles like trucks.
 

gtman

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So you've driven 10 minutes straight at 105mph at night in NJ? Sounds risky, just sayin.:cool:
 
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CivicXI

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So you've driven 10 minutes straight at 105mph at night in NJ? Sounds risky, just sayin.:cool:
No, not NJ. I make frequent trips to Vermont and New Hampshire. Most of the drives involve heading out early (4-5am) and coming home late (1-2am).

Last night I made it from Lake Placid back to NJ in 3 hours flat and for the first hour and a half, I saw maybe 10 cars on the road.
 
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CivicXI

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Most vehicles are close to linear if you plot MPG vs MPH, even heavy and un-aerodynamic vehicles like trucks.
Doesn't that sound odd though? Since speed increases linearly but drag is squared? It doesn't even make sense to me as an engineer although its very impressive.

My old mitsubishi at a steady 90mph was getting literally 15mpg.
 


lzaffuto

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I get about ~31mpg on a pretty brutal mostly city 45 mile round trip commute that with every other car I've only managed to get ~18-20mpg before. I also average ~43mpg at 70mph on highway trips. I'm really happy with the mileage and I don't really worry about gas prices anymore.
 

Civic416

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I would agree with those numbers. I'm only on my second tank (91 octane) but I can tell that city will be in the low 30s and highway 40-45. Really happy that I can maintain 120-125 km/h and still get that sweet mileage. Plus the weather is cold here and I might get even better numbers in the summer. I love how light the car is. Still breaking it in but no real need to go over 3000rpm. You can still be first off the line (usually) while feathering the throttle and then you just coast...
 
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CivicXI

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Don't have all the data yet but it seems like at 75mph, instead of 38mpg, i'm getting 36mpg between 60F+ and <30F.

I expect probably 33-34ish when it dips into the teens.
 

Michael90

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Got a 2017 EX here. 31/40 on the sticker. Been driving in the city since purchase and have only seen around 23 MPG

Just curious are these sticker numbers only achieved with the ECO button on???
 

turbo lover

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In some cities, sticker numbers are never achievable. There is simply too much stop and go and idling.
 


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CivicXI

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I've come to discover that the turbo engine, at steady state low RPM cruising, uses less gas than the less powerful 2.0 normally aspirated engine.

But when you're on the throttle, uses significantly more gas proportionally.

Another thing I've noticed, on my hatchback, when I let off the gas, the MPG meter slowly rises to 40+. But on my girl's EX-T, same engine, when I let off the gas, the MPG meter goes immediately to 40+. I wonder why that is...
 

NotSerious

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Got a 2017 EX here. 31/40 on the sticker. Been driving in the city since purchase and have only seen around 23 MPG

Just curious are these sticker numbers only achieved with the ECO button on???
The Civicx with CVT gets very good mileage, but there is no breakthrough technology in it. It is just a small engine with a transmission (CVT) that gets a little extra mileage by softening the acceleration and keeping the car in the ideal gear ratio to maximize torque.

Some people seem to think that the Civicx has a magic engine that can get 40 mpg under acceleration. It doesn't. When the car spends a large percentage of the time accelerating and decelerating (as you would if most of your driving is short urban trips), you are not going to see anywhere close to the manufacturer's claims. 23 MPG is about what you should expect in urban driving. I get 27 mpg with about 70% highway and 30% city and less than 25 mpg in city-only driving.
Read here. There are others in NYC that get similar mileage to what you report if most of their driving is urban stop and go.
http://www.civicx.com/threads/damn-you-mpg.10250/

Take your car out for a weekend run to the Adirondacks and you should see the mileage climb to well over 30 mpg. Your in-city mileage will improve marginally if you keep it in "D" with the "Econ" button on. But then you will lose all of those stoplight to stoplight races that you find yourself in, in urban areas. Or just leave your car in "S" if you want to keep up with the aggressive drivers in the city and accept the poorer mileage.

The fact is that the manufacturer's claimed mileage does not reflect real world conditions. They exaggerate their mileages to help them sell cars.

"More Reason to Be Skeptical About New-Car MPG Claims"
http://business.time.com/2012/12/10/more-reason-to-be-skeptical-about-new-car-mpg-claims/
 
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CivicChina

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I can get easily the advertised mileage in the city and i can do even better on the freeway, without going too slow. I think in the real world if you want to move quickly the 6mt is slightly more economical than CVT.
 

Civic416

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Would that still apply if you used the paddle shifters and geared to maximise throttle efficiency in every situation?

I am gentle during break in, always in D w cvt, just short bursts.. coasting past cars, except the odd sleeper civic which fly past.

Eager to know how a full tank in S mode might compare
 
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CivicXI

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I think S mode uses like 1/3rd more gas because the turbo is almost always in boost.
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