Hyundai Forums banner

41 - 60 of 90 Posts

·
Registered
Joined
·
1 Posts
I do probably 80/20 city/highway, and I'm averaging around 18mpg with my 2019 2.0T. In retrospect, I probably should've got a plug in hybrid Pacifica based on my driving habits, but I'm pretty satisfied with the Santa fe overall, mpg aside.
 

·
Registered
2020 2.4 SEL FWD
Joined
·
82 Posts
I'm in the south where I've rarely used heat or cool since buying the 2020 2.4 SEL FWD. I'm a fuzz under 1000 miles. Pencil and paper says I'm getting 29.5 mpg while the trip computer calls it a very impressive 31.9 mpg. I wonder if there's a dealer adjustment to bring the car computation closer to reality?
 

·
Registered
Joined
·
641 Posts
As long as the error is consistent you can just make a correction.
My Tucson dash reads 7% higher than reality.
31.9 vs 29.5 is 8% high.
 

·
Registered
Joined
·
126 Posts
Unfortunately it's not consistent. It's not possible to see the calculation used, but at a minimum you can tell by experimentation that recent MPGs are valued higher than older MPGs... possibly older MPG data is thrown out.

By this I mean if you drove the first half tank highway and the second half tank city, you would get a different "calculation" than if you did the opposite, despite the actual being identical. Or, you could drive the first half tank highway and then leave the car to idle for a while...the MPG "calculation" will dip much further than reality because it is more recent.

If you drive fairly consistently, the computer will give a fairly consistent error, and is nice as a general estimation. But for real diagnostics then pen and paper will always be a better bet.
 

·
Registered
Joined
·
126 Posts
After checking several tanks, some all highway, some all city, I'm confident mine is pretty consistent.
It will be consistent if you drive consistently (i.e. some all highway or some all city, as you stated). If not, the only way to get accuracy is with pen and paper. The shame of it is that the car knows how far it's traveled and how many gallons are left...an error as large as it has is unnecessary.
 

·
Registered
Joined
·
641 Posts
Let me put it this way, all highway, mixed, or all city, it's always 7% off.
Now that I'm confident in that I don't need pencil and paper to spot anything unexpected.
I made a living for years calibrating test and measurement equipment.
Some things cannot be "adjusted". You just have to live with a correction factor.
I hope you now understand my point. Or maybe you just insist on having the last word?
 

·
Registered
Joined
·
126 Posts
Let me put it this way, all highway, mixed, or all city, it's always 7% off.
Now that I'm confident in that I don't need pencil and paper to spot anything unexpected.
I made a living for years calibrating test and measurement equipment.
Some things cannot be "adjusted". You just have to live with a correction factor.
I hope you now understand my point. Or maybe you just insist on having the last word?
Are we comparing qualifications now? I spent over 20 years in aircraft test equipment.

Here's an experiment. Take a picture of your MPG on the dash. Let the car idle for 30 minutes. Take another picture of the MPG on the dash. Fill up and compare the actual MPG to what is on the dash. Take a picture of the receipt. If the difference in MPG is still 7% off I will pay for that receipt.
 

·
Registered
Joined
·
170 Posts
The cheapest part of car ownership is gas. I moved from a Prius to a Santa Fe and for the much improved vehicle don’t care about mpg.
I have just completed 13 years with my 2007 Santa Fe Ltd. 3.3L AWD.

I now have 322,000km - 200,000 miles on it.

My costs have been:

02 18 20 - Year 13 25,341km 322,000km

Fuel $3,273 $.129/km $42,838

Purchase Price $2,923 $.146/km $38.000

Maintenance $522 $.020/km $21,909

Insurance $1,147 $.045/km $15,951

TOTAL $7,865 $.309/km $118,698 $.369/km

You can see that fuel is not the cheapest cost,
 

·
Registered
2019 Santa Fe Ultimate 2.0T HTRAC
Joined
·
488 Posts
Bad experiment...
If the mpg was mostly hwy and less than 1/4 tank remaining, the 30mins idle might not have an impact. I have not checked the mpg after fillup as per ur test because I configure the carputer to auto reset on fillup. But for my 07 Sonata, the mpg stayed the same after fillup, I manually reset it everytime. If the SF doesn't behave like that, then Hyundai screwed up!
 

·
Registered
Joined
·
126 Posts
Bad experiment...
If the mpg was mostly hwy and less than 1/4 tank remaining, the 30mins idle might not have an impact.
My experience and some others on here found Kia/Hyundai weighs recent driving more than earlier driving on the carputer MPG calculation. This is why idling after 3/4 of a tank used as you said shouldn't have much of an impact, but somehow does.

I had to do some work on some trailer lights while the engine was running, I think it was an hour. The MPG went from something reasonable to so low that the carputer put dashes up (---) for MPG.
 

·
Registered
Joined
·
103 Posts
Don't mean to bust anyones bubble - - but the MPG readout on the dash is 99% accurate.
The ECU measures the flow of the injectors in relation to the speed the vehicle is moving.
Only if you install other size tires will your readings be off.

Every fuel pump has a pressure variance for shut off - - - even if you used the same pump for all of your fill-ups the pressure that causes the pump to shut off will be different every single time.

The only way to accuretly measure your actual pumped fuel would be to weight the car during every fill up.

Sorry - - the readout from our mileage is correct.
 

·
Registered
Joined
·
103 Posts
My experience and some others on here found Kia/Hyundai weighs recent driving more than earlier driving on the carputer MPG calculation. This is why idling after 3/4 of a tank used as you said shouldn't have much of an impact, but somehow does.

I had to do some work on some trailer lights while the engine was running, I think it was an hour. The MPG went from something reasonable to so low that the carputer put dashes up (---) for MPG.
Because your vehicle was not moving - - - - - - you can not have miles per gallon if you are not driving......miles.
 

·
Registered
Joined
·
103 Posts
Are we comparing qualifications now? I spent over 20 years in aircraft test equipment.

Here's an experiment. Take a picture of your MPG on the dash. Let the car idle for 30 minutes. Take another picture of the MPG on the dash. Fill up and compare the actual MPG to what is on the dash. Take a picture of the receipt. If the difference in MPG is still 7% off I will pay for that receipt.
Because of the pump BACK PRESSURE variance - - - - - They are broad and not specific.
The ammoun of fuel for a fill out will be different every time creating an unknown variance.
 

·
Registered
Joined
·
126 Posts
Because your vehicle was not moving - - - - - - you can not have miles per gallon if you are not driving......miles.
Exactly, I was wasting fuel and driving zero miles. But does that mean that the entire tank which started at 25 MPG ended up less than 10 MPG after idling as the carputer said? Fill up stations are inaccurate but would they account for the up to 10% variance owners have been experiencing?

Sorry - - the readout from our mileage is correct.
Why apologize? We would all LOVE for the carputer MPG to be correct. It is not only higher than any fill up calculation, it is much higher than the manufacturer claims or the EPA has measured. I'm just looking some evidence that it is, rather than blind belief.
 

·
Registered
Joined
·
103 Posts
Exactly, I was wasting fuel and driving zero miles. But does that mean that the entire tank which started at 25 MPG ended up less than 10 MPG after idling as the carputer said? Fill up stations are inaccurate but would they account for the up to 10% variance owners have been experiencing?



Why apologize? We would all LOVE for the carputer MPG to be correct. It is not only higher than any fill up calculation, it is much higher than the manufacturer claims or the EPA has measured. I'm just looking some evidence that it is, rather than blind belief.
It is not blind belief - - - it is a very simple math algorithm that uses injector flow and distance traveled to determine the usage of fuel in a given engine. This software is decades old now.
EPA MPG is an estimate - - - EVERY car I have ever owned I have been able to achieve better MPG numbers - both in city and highway.

YES the pump variance can and will account for a 10% "so-called" difference. ----and YES you idling the vehicle for 1 hour is HUGE and will drop your average mpg that much. The math is quite simple really.

Everyone getting lower than their computers is solid proof that a wide gas station pump variance in back pressure shut off valves exist.........Not to mention expansion and contraction of fluids in different climates.
Each pump can be different when they actually click off.

The only way to be sure what you put in every time is to have the car on a scale and to refill the car to a specific weight.

In regards to the MPG computer it is always right within a 99% margin. This is science and math - - -plain and simple.
 

·
Registered
Joined
·
641 Posts
but the MPG readout on the dash is 99% accurate.
The ECU measures the flow of the injectors in relation to the speed the vehicle is moving.
Just because you know there is a way to make the measurement does not mean the measurement is accurate.

One does not lead to the other. You could just as easily claim it's 100% accurate.
This is science and math - - -plain and simple.
So, show us the math. Show us the science. Include error analysis.

The only way to be sure what you put in every time is to have the car on a scale and to refill the car to a specific weight.
LOL, there are more clever ways to do it, believe me.
 

·
Registered
Joined
·
126 Posts
Everyone getting lower than their computers is solid proof that a wide gas station pump variance in back pressure shut off valves exist
This is the opposite of proof. If there were these variances, then some fillups would show higher, others would show lower. Please show a source that shows gas pumps can turn off 10% early or late (over a gallon difference) even on the same pump.

The only way to be sure what you put in every time is to have the car on a scale and to refill the car to a specific weight.
Filling up with a funnel sounds a whole lot more accurate/easier than weighing a car.

In regards to the MPG computer it is always right within a 99% margin. This is science and math - - -plain and simple.
Perfect. Now all we need is a single source that shows this is the case. And believe me, I want it to be.

SHOULD YOU TRUST YOUR CAR’S MPG DISPLAY? "The results: every vehicle we’ve tested has returned a significantly lower mile-per-gallon figure than the one displayed on the dash. If this was simply some kind of rounding error, you’d think that there would be a few cars that provide better fuel economy than the car recorded, but not one of the cars we have ever evaluated has ever delivered higher fuel economy than the one that was displayed. "
 

·
Registered
Joined
·
3,361 Posts

·
Registered
Joined
·
103 Posts
https://www.nhtsa.gov/sites/nhtsa.dot.gov/files/documents/811192.pdf - - - -
Excerpt
Due to the prevalence of fuel-injection technology and electronically controlled engine operations, virtually 100 percent of new vehicles produced in 2008 and beyond have the necessary data on-board to compute instantaneous fuel economy and trip-based fuel economy measures. In fact, most if not all vehicles produced after 1996 that have an OBD-II data bus should be able to provide the necessary data for a FEDI without additional fuel usage sensors.

Just to be clear I am talking about the instant mpg readout - - -


Excerpt -
But is it really that bad? Wards Auto suggests not--and says that, contrary to previous research, trip computers are probably the most accurate way of determining your real MPG, more so than the traditional tank-to-tank method.
Wards offers several reasons for this line of thinking.
One is that if most vehicles were over-reading, then most vehicles would happily beat their EPA-rated economy figures when driving in the real world. In their experience, and in our own experience, that isn't the case--most vehicles are pretty close to the EPA numbers.
The next is that the same software used to calculate instant and average MPG also tells you how much fuel you have left in the tank.
At what point does the fuel computer suddenly start telling the truth about your mileage--before, or after the range indicator has dropped to zero miles and you're out of fuel?

It was curious that this article was the first posted by google yet it was missed???????
 
41 - 60 of 90 Posts
Top