This Is What It Takes to Hit 35 MPG in Our Hyundai Santa Fe Hybrid: Motor Trend
Posted by HawtGarbage918@reddit | cars | View on Reddit | 57 comments
Posted by HawtGarbage918@reddit | cars | View on Reddit | 57 comments
Ibotthis@reddit
tl;dr: don't speed. That's literally it. Normal driving behavior in the city sees at or better than expected economy, and on the highway if you drive the posted limit you get very close. Driving 120-130km/h tanks the fuel economy of all cars compared to 100 km/h and has been known for decades. Drag is not linear, especially when dealing with giant boxes.
SkellyJelly33@reddit
They were driving 5 under the limit on the highway and it still wasn't enough to hit the epa estimate for highway
megacookie@reddit
Apparently the EPA highway fuel efficiency is measured at an average of 48 mph with a max of only 60. Could explain the difficulty in trying to match those figures at 65-70 mph.
UmaThurmish@reddit
drag is linear. whats not linear is the engine efficiency, engines are most efficient somewhere around 2000-4000 RPM.
LordofSpheres@reddit
Drag is explicitly nonlinear with velocity.
diethyl2o@reddit
The real tl;dr is don’t break. That doesn’t mean crash into everything, but rather accelerate only when you know you won’t have to slow down soon after. Anticipate and have enough in front of you to use the natural resistance to slow down. And when you accelerate, do so gradually. Just because your car can go 0 to 60 in 5 seconds doesn’t mean you’re not allowed to do it in 15 seconds.
accountforrealppl@reddit
Comparing city vs highway driving you're right as this is why city mpg is usually worse. But for cruising on the highway, speed will absolutely kill your mpg past a point
Wind resistance force increases with the square of speed, so it builds up pretty quickly. The differences you will see between 80 mph and 50mph are substantial
People often confuse this in the real world because fast speeds are synonymous with the open road and slower speeds are associated with stop and go traffic, but apples to apples speeds above like 50-60mph will start to kill your mpg pretty quickly
Iriss@reddit
All driving would be so much more pleasant if people cared about maintaining momentum.
It's a no-brainer as a cyclist because you have to do the work yourself to recover the momentum. Drivers will do stop-and-go bullshit forever instead of coasting/smoothing at all.
TheLoneStarResident@reddit
When it rains in my city traffic is so much more smooth because people keep space, go slower, have fewer lane changes, and don’t use their brakes as much.
Sad that people can’t see this and apply it on all conditions
diethyl2o@reddit
100%. I’m also a cyclist but didn’t consciously explicitly think about it when I wrote this. Now that you mention it, I can totally see how my cycling influences my driving.
So the real real advice is to force every able-bodied driver to bike in the city for a week ;) now that would make the world a better place.
Iriss@reddit
Ahahaha, if only.
Now go get run off the road by a driver before getting screamed at by a pedestrian for being on the sidewalk.
Effective-Ad-789@reddit
This implies driving the speed limit is “normal”, which in many places it isn’t. Flow of traffic typically is faster 🤷♂️
lee1026@reddit
The problem is that the EPA have a rulebook for determining the mpg ratings in the window stickers. And they measure fuel economy at the speeds from that rulebook, and it is pretty slow.
Automakers can read that rulebook and go "hmm, so we just need to really efficient at those speeds, got it".
leedle1234@reddit
The EPA test that determines the highway mpg number is a simulated 12 mile drive with an average speed of 48mph. It's the reason most normal cars for decades now will significantly exceed the EPA highway mpg.
Ibotthis@reddit
that's fine but manufacturers and regulations aren't built around these anecdotal outlier cases, they are tested around norms and controlled conditions. In many places 10 over the limit might be common, or maybe 20. I have long stretches of highway where people routinely travel 140km/h but it'd be ridiculous for me to expect the same economy as if I were going 100. Individual driving behaviors are way too variable. I know a ton of people that floor it off the line and then travel 5 under the limit. These people also likely have issues hitting advertised fuel economy despite their overall slower pace. I have a manual, so if I choose not to shift to a higher gear and just drone along at a high RPM, I could be traveling slowly but inefficiently. It's unreasonably and unnecessary for them to test to these variables, which is why I'd bet all the manufacturers are testing to averages. If the average limit is 110km/h across the US, then highway economy is estimated based off this speed, and from the article the write was able to achieve advertised economy around 105km/h, which is likely the average they tested to.
Effective-Ad-789@reddit
Yes but there tests are supposed to help people to know what kind of mileage they can get in real world scenarios. When the real world results and the test results are so different there is a problem - mainly that the test dosent simulate reality very well.
aprtur@reddit
It's a relative benchmarking tool, not an absolute. That being said, what is probably making things even more unpredictable nowadays is the much greater variance in drivetrains and how each plays to the standard test - especially as ECUs learn driving habits. For example, hybrids will generally skew their combined rating due to city metrics being very high on electric assist, whereas a small displacement turbo engine that's geared high could excel at highway driving in the test. Both of these wouldn't be accurate for someone predominately driving on the highway at, say, 80mph, since the hybrid would have a dramatic loss of its charge, and a turbo engine would most likely be in boost at that speed (you see this with F-150 V6T vs V8, to an extent), taking both out of their test loop efficiency range. Also, driver A who hypermiles with minimal throttle inputs and is very conscious about braking will have a much higher readout vs driver B who is constantly either on the throttle or on the brakes like a light switch.
TLDR, you can keep messing with the test, but if it's not a test loop that mimics the owner's habits, it's always going to be off varying degrees. You can only use it as a general comparative benchmark.
palefacekid14@reddit
Don't drive like an asshole, save gas.
Critical-Magician421@reddit
Does anyone have any idea how he measured this? Is this something you could actually see on the car?
pppjurac@reddit
It is accelerometer. Virtually all smartphones have built in accelerometer.
Captain_Alaska@reddit
Based on the test data on the bottom a fairly safe assumption is an accelerometer is a part of the test equipment they put on the car.
You could measure this with a smartphone if you wanted to
MechMeister@reddit
I get 34mpg at 80mph in my CRV 2.4 earth dream just by using non-ethanol gas. Using E10 it drops to 30 or 31mpg. Well worth a few cents per gallon
tempestokapi@reddit
Where do you find non ethanol gas in the U.S.
Hnry_Dvd_Thr_Awy@reddit
1) IDK what the Koreans do wrong with fuel economy but I've never gotten anything close to the rated MPGs in real driving. I've at least gotten soft of close in many brands. 2) It's 2026 - can we pleaseeee calibrate the MPG readouts in cars? My 1990s Metro had an mpguino and was within a couple of percent for every tank.
BoofMasterQuan2@reddit
I regularly get 50 without trying in my sonata hybrid. Many times above 60 so your anecdote doesn’t mean shit
Hnry_Dvd_Thr_Awy@reddit
I’m glad you got that off of your chest.
BoofMasterQuan2@reddit
Yep no problem
europeanperson@reddit
Yeah I don’t get how it’s not able to be accurate. Fueling is so precisely controlled, genuinely curious how it can’t be reliably measured by the car’s computer.
KSoMA@reddit
The fuel isn't what's inaccurate, it's the mileage.
europeanperson@reddit
I guess who knows what information they’re using to do MPG calculations. Even from that article you linked,
“Electronic stability control systems, mandated by law, need speed and direction-of-travel information in order to rein in an out-of-control car. To obtain it, those systems use yaw-rate sensors and accelerometers, in conjunction with individual wheel-speed sensors, to continuously calculate a vehicle’s actual velocity. Oddly, that information never makes it to your speedometer.”
Even if it’s not used for the speedometer, it doesn’t mean it couldn’t be used for MPG estimations.
JoeStapes@reddit
My car consistently reports 5% higher mpg than what I actually get. I’m wondering if there’s a standard that says the display has to be accurate to within 5%, and the manufacturers intentionally fudge it as much as they can.
hells_cowbells@reddit
That seems pretty low for a hybrid. Last year at Thanksgiving, I rented a RAV4 Hybrid to go visit family. Trip was about 8 hours one way, mostly open interstate around 75MPH, with maybe an hour in the city. I averaged 37 MPG, and I was not babying it or using any special techniques.
OldRed91@reddit
Americans will do anything other than drive a sedan.
MechMeister@reddit
Because you cant fit shit in modern sedans especially if you live in mountainous areas, they dont have enough ground clearance anymore.
ZombiePope@reddit
A 1.6 in a 3 row SUV is pretty fucking grim.
Da_Funk@reddit
Our 2024 Santa Fe Hybrid's lifetime MPG so far is 30. And my wife has a lead foot.
Electrical_Eye_6503@reddit
And the funny part is the article basically says the “secret” is just not driving fast on the highway. Once you start cruising at 120–130 km/h the aero drag destroys fuel economy on these giant SUVs
besselfunctions@reddit
Automakers have been wrong before: https://www.epa.gov/recalls/fuel-economy-label-updates
Bounce_hit@reddit
I had a similar car MPG vs actual MPG in my CR-V Hybrid.
The car's computer was routinely overestimating my MPG by about 2 MPG. I feel that it is deceptive but hey whatever I average 34-35 MPG over most tanks and drive 75mph
I_like_cake_7@reddit
I’ve noticed that the trip computers in a lot of modern cars are too optimistic with their MPG estimates. It’s almost always lower in reality when you hand calculate the actual MPG.
KSoMA@reddit
Cars usually do this because they are allowed to overcount on speedometers by as much as 10% but in many regions they are not at all allowed to undercount the speed. Because of this the car estimates a speed that can be 5-10% faster than you're actually going and this will end up affecting most other measurements related to distance travelled (odometer, fuel economy, service reminders, etc).
Bebealex@reddit
I have written to multiple websites, car an driver, motertrend, cars oops asking maybe they could do a piece on the fact that iv never had a car mpg reading be accurate. Always 10% more accros multiples brands.
Never heard from anyone :-/
Jam_Bannock@reddit
I looked into this a bit. The car calculates its fuel economy from its estimate of how much gas it injected. It's an estimate because it depends on various factors - injector pulse duration, fuel pressure or density variation. Because it's an estimate, it can be quite wrong, which makes the mpg estimate have a large margin of error. All estimates have a margin of error, so they just roll with it. Keep in mind, this is a layman's understanding of what's said across various websites.
lee1026@reddit
The injector is pretty precise. It needs to be, or else emissions is gonna suck.
Jam_Bannock@reddit
That makes sense. It also underlines what happens a lot on forums: it's easy to get misled by confident-sounding but ultimately, factually wrong posts.
Bebealex@reddit
It's odd because using an obdii dongle or back the day, a standalone reader, usually showed me the correct reading.
(Same speed reading)
qpaleoskeidj@reddit
any idea where I can get my hands on that tape measure?
FMJoey325@reddit
My Subaru is usually ~3 MPGs too optimistic. I just assumed the calculation is done on a rolling basis and the window isn’t very large to back calculate from. But it’s ALWAYS optimistic.
ads1031@reddit
My CTS was also always 2mpg optimistic. I started to wonder if some amount of fuel was evaporating and not being accounted for by the trip computer.
Bounce_hit@reddit
Sorry babe, the "Centimeters" side was misprinted as "Inches"
wagwagwag@reddit
I may be the exception - my TDi is within 1mpg of hand calc, and it's often pessimistic.
Prestigious_Pin_4947@reddit
TFL does this sort of calculation on every fuel economy test. They do a two click method of filling up the gas tank, and it seems that pretty much every trip computer (of the videos I've seen) over estimates the fuel economy.
ethereal3xp@reddit
How much more expensive is IONQ9?
_Thorshammer_@reddit
“You can’t cheat physics” should be etched into every hybrid drivers window.
arsinoe716@reddit
If you want good fuel economy, you have to drive to get it. That means no hard acceleration, unwarranted braking, 80 mph speeds.... No different if your car is rated to hit 70 mph in 8 seconds. You have to floor it.
dr2fish@reddit
Interesting. I picked up a ‘26 Tucson hybrid a few months ago and (accodring to the possibly optimistic computer) have averaged the advertised 37 mpg over a range of driving conditions without any special effort. If I intentionally hypermile I can easily hit 40+ in round-town mixed driving. I’ll have to remember to hand-calculate the next tank to compare.
Przedrzag@reddit
A Tucson has better aero than a Santa Fe by virtue of not having a bed; the difference might just be bigger than what Hyundai claims in their figures