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Don’t trust the MPG that the car is telling you. Do the math yourself. You will likely find that the vehicle’s indicated MPG is about 1+/- MPG high. That has been my experience with three vehicles though my ‘14 A6 is the most accurate with the error averaging just below 1. My ‘17 F150 and long ago ‘06 G6 both were over 1 MPG high.
Don’t trust the MPG that the car is telling you. Do the math yourself. You will likely find that the vehicle’s indicated MPG is about 1+/- MPG high. That has been my experience with three vehicles though my ‘14 A6 is the most accurate with the error averaging just below 1. My ‘17 F150 and long ago ‘06 G6 both were over 1 MPG high.
This also has been my experience when I compare indicated MPG to calculated MPG, maybe 1 mpg higher from the computer.
However, this level of variation doesn't seem like a big deal to me, particularly given that it's easy to spot and is consistent over time.
Makes one wonder why the calculated MPG is the one instrument indication that is not accurate on modern vehicles? Not really a mystery. Deceptive marketing is the answer.
Makes one wonder why the calculated MPG is the one instrument indication that is not accurate on modern vehicles? Not really a mystery. Deceptive marketing is the answer.
More likely it's a product of the limitations of the technology, I think.
My 1LT is THE gas millage champion in my driveway. Can get better millage than my wife's Kia Optima 4 banger. Always gets better millage than my truck too (Toyota Tacoma.)
Just like others.... you millage will vary and really, I could care less what the millage is on my C7 or my C3. Just drive and enjoy them.
Same here. 2011 Tacoma and my wife's 2015 MustangGT 6 speed. The Mustang really isn't bad/ 18 in town and 25 on the interstate. But last summer she took the Tacoma to the beach (6 hr drive) on Saturday and I came down on Monday in the Stingray. I checked the overall mileage for that trip when I parked and was blown away. 30mpg. Later that evening I did a poll of the 8 people who were there asking them to guess my mileage. I think there were a couple who actually thought I might be fibbing.
Last edited by CraigStu; Jan 24, 2021 at 05:11 PM.
As noted, you can do great on the highway cruising at low RPM, but in virtually any other circumstance, it drops off quickly... big motor is going to use a lot at idle and low speed street driving in lower gears, so if that was a big chunk of what you are doing, I'm not surprised.
While many may not care from a monetary of fun factor standpoint (and I'm among them) if your car is getting significantly less than it should, it is likely indicative of some sort of mechanical issue, and that I care about.
More likely it's a product of the limitations of the technology, I think.
Not buying that argument since the indicated MPG is always on the high side. Also makes planning fuel stops on a trip when the “miles to empty” counts down more rapidly as you approach empty.
Every car that I've owned with an MPG meter has indicated a little higher than MPG calculated on the basis of fillups. I think it's likely that the meter is an indirect calculation that can be sllghtly skewed. (I read details at some point years in the past but can't remember specifics.)
Maybe there's someone here can enlighten us. I have several auto designers and engineers in my extended family but no one who would be expert in this.
This would be a great question for the "Ask Tadge" threads if they ever resume.
Last edited by fsvoboda; Jan 25, 2021 at 07:20 PM.
I have done lots of highway driving with mine. The mileage is an amazing bonus. One of my friends was bragging his Prius can get 500 miles on a tank of gas, so I showed him this picture of my fuel range on my C7 dashboard....
. He couldn't believe it.
When I took my brand new Z51 cross country, i stopped at a motel in Utah and pulled in next to a brand new Porsche 911. The owner and his wife were sitting out in front of their room as i got my suitcase out of the back. he said the car looked good and asked me how fast it was. He said his had a top speed of 175. I told him car was brand new so I haven't had a chance to open it up yet but I thought it would probably be somewhere in the same ballpark. Then he asked about my gas mileage and I told him I was averaging 26-27 mpg all the way out from NJ. So then he tells me, his wife gets 28.5 mpg when she drives. To which I answered... yes but mine cost less then $64000. That was when his wife started laughing out loud as i unlocked the door and went into my room.
True story.
Last edited by blueray16; Jan 25, 2021 at 11:12 PM.
Every car that I've owned with an MPG meter has indicated a little higher than MPG calculated on the basis of fillups.
Based on my calculations the onboard computer reports 1 MPG more. So many factors go into mileage (temperature, tire pressure, altitude, etc) that this seems to be an acceptable margin of error. Since you can't use every drop in the tank you'll always have to fill up slightly sooner then predicted. However your talking just 30 to 40 miles here if you use the low fuel light as your limit. At that point about 2 gallons are in reserve.
My best tank was 457.1 miles of driving while getting 28.7 MPG with an average speed of 70 MPH. Driving slower could easily yield a 500 mile range. Truly amazing for a car with this level of performance.
I got about 27 MPG with mostly highway driving with a few foot to the floor moments here and there. Unfortunately, I don't have a lot of data points with the C7. My Camaro SS 1LE got 25 MPG in a similar driving scenario, for reference.
I have a few data points with the Camaro SS 1LE now. I get about 14 MPG in the city. I would think C7 would have about 1 MPG advantage due to the weight difference if I were to drive one currently. But yeah, I more monitor the gas mileage to monitor the car's health. I would say the fuel mileage isn't bad at all for the power you get out of these cars.
Originally Posted by 19672014
Makes one wonder why the calculated MPG is the one instrument indication that is not accurate on modern vehicles? Not really a mystery. Deceptive marketing is the answer.
Actually, the one in my friend's Mazda6 is decently accurate. It's usually within 0.3 L/100km(it's displayed in metric) of the actual gas mileage, and it can either underestimate or overestimate.
The one in my Camaro is consistently about 10% more optimistic than the actual gas mileage. Might be an algorithm difference here.
Last edited by UnknownJinX; Jan 27, 2021 at 07:42 PM.
I got about 27 MPG with mostly highway driving with a few foot to the floor moments here and there. Unfortunately, I don't have a lot of data points with the C7. .
