09 ORM Auto tranny . Just purchased .1 tank highway , no air avg @ 65 mph or a little less . Some stop and go ( 4 small towns with a few red lights)
Computer 40.5 , hand calc. 41.5
1 partial tank city @ 85 miles , lots of stop and go traffic , very little highway . Not very aggressive but not totally passive either . 27 mpg computer and 24 mpg hand calc.
Third tank higway same as first 40.5 computer and
38.7 hand calc. .
So obviously this car does great on the highway , not so great in town.
Should I be seeing this large a variation ?

 

113 Km
8.7 Litres

Thats 30.2MPG or 7.8 L/km.
80% city, 20% highway

THe car is still breaking in, as we've only got 120 Kms on the engine. Also the gas attendant filled it all the way to the top, pressing the knob like 5 times, each time pulling out.

----- Out of topic brain dump ------
The car is very zippy. I did 5kRPM a few times, but it felt suicidal. Did 4k RPM when passing. Changing gears between 2k-3kRPM felt normal, and the traffic could keep up with us (but barelly). I've noticed to stay steady with traffic you'd have to stay at 2kish RPMs.

You can definatelly feel the vtec kicking in at around 2.8k - 3.0k RPM.

Also, what I've noticed is that you can run in traffic on gears anywhere from 2 to 5. Gear 2 at40- 50km/h would give you high RPM, and would shoot you up like a rocket when gas pedal pressed. Gear 3 is nice passing gear at that speed. Gear 4 well... gives you a bit of power, maybe stay at a steady speed going up a hill, I am sure it is preatty good at higher speeds . And gear 5 at 60km/h will accelerate you slowly on a straight line, forget hills. Pass other cars on gear 5 if you have time, and want to exchange long smiles with the driver being passed. If they don't want to return your smile, well you are in for one long uncomfortable moment..........

 

First long highway trip -- Salinas to Redding in California.

Going North: 354.3 miles, 1.000 gallons, 35.4 mpg. Gauge said 37.9. Rainy, lots of traffic.

Going South: 357.1 miles, 9.811 gallons, 36.4 mpg. Gauge said 38.9. Dry, light traffic.

This is consistent with the difference between the gauge and calculated results that I've been getting for my car -- gauge reads high by roughly 2.5 mpg over the life of the car. However, the mileage, both highway and in town, is several mpg higher than the EPA ratings, which makes me happy.

Both of these trips included a bit of climbing on Highway 152 between Hollister and Santa Nella. The car handled it well, holding speed on the cruise control (70 mph), although it had to shift down to third gear (a bit less than 5000 rpm) to do it in some places. While noisy, it pulled strongly without any problems. A/C was on during most of the trip, defogging on the way north and cooling on the way south.

This is an -09 Fit Sport AT, without Nav. Tires at 35 psi all around.

 

Just did 1600 miles to Zion & Bryce Nat'l Parks and back. Driving 70-80mph most of the time (except for holiday jams) my mileage was pretty consistent at 34-35mpg (actual, the gauge is always 3-4mpg's high).

HOWEVER, the tank of gas I got in Utah gave me 42mpg (and it was only $1.62/gallon) ... which shows that in California we not only pay extra for oxygenated fuel, it kills our mileage by a good 20%. /rant

 

Hey, guys. I just thought of something that might explain the difference between the computer and actual mileage. (If this has already been mentioned, please ignore) Often times, the speedometer and odometer is tuned at the factory, but it is most of the time, off by a bit. For instance, every time I have tracked my MPH on the speedo and GPS/radar, it has been off. This is on 100% stock vehicles, down to the tires. Also take into account that the fill line at every fill up is not going to be the same (meaning, you're not pumping to the exact spot as the last fill up, which throws off the calculations).

The point I'm getting at is, the computer actually COULD be more right than the actual calculations. The computer does not take the calculations from the odometer, so it is not affected by the factory speedo/odometer settings, nor the tire sizes. Nor is it affected by the inconsistent fill line. This is the case with the aftermarket ScanGaugeII as well. I believe it is more accurate than the traditional mileage divided by gallons method.

Just a thought.

 

Wishful Thinking.
Let's face it, Honda WANTS us to tell everyone about our GREAT gas mileage. This is simple marketing.
CALL AND TELL HONDA THAT THEY NEED TO FIX THE PROBLEM!!!!!

 

It's not just Honda. Every BMW I've owned also had this "problem." Also, my Jeep, Toyota, etc.

I can't say which is more correct, but *I* think there is more margin of error with the traditional "fill and divide" method for those reasons stated above.

 

I always had this suspicion as well. Thing is, 4 mpg off is a huge difference. Hypothetically, if you had a 10 gallon tank and ran 400 miles and filled it up with 10 gallons, that's 40 mpg. 4 mpg would equate to 360 miles on the same tank. That's 40 miles off! So any variances in fuel fill up, odometer reading, tire circumference, etc., should not add up to that many miles off, theoretically.

Still, I agree with you in that the FE computer may not be as inaccurate as we suspect, but may actually be MORE accurate than the manual calculations we've all been practicing all our lives.

 

I don't think the difference would be 10% either. Generally speaking, the difference between the odo and GPS/radar was around 4%.

I think a more accurate MPG figure could be had by looking at both the computer MPG, and figuring multiple MPG figures from a GPS mileage/gallons (but you'd need a lot of samples of that). I believe the gap between the two figures would be closer.

 

FWIW, I previously owned a Toyota Camry Hybrid and found the MPG estimate to be quite accurate. 1-2 MPG either way.

 

You guys crack me up. I realize that the gas tank does not always fill to the same level and that sometimes we drive harder or have more weight in the car and that can effect mileage. Mileage is figured by how many revolutions your tires make (actually your transmission). GPS is NOT used. Unless you"re not driving on stock tire sizes multiple manual calculations are VERY accurate. Calculators don't lie. ON AVERAGE I am getting 4 MPG less. Nuff said.

 

My 94 Corvette (older technology) is also quite accurate.

 

Not necessarily. You can fill up your tank from one station and the pump will stop at X level, while the next fill up at another station will can fill it less (or more) than X level, skewing the true mileage.

 

I never said GPS was used. However, I HAVE used GPS and radar to figure out the speedo error.

Have you verified your actual miles driven via GPS or other sources? Or checked your speedo by other measures? If not, no matter how many calculations you make, it will be off.

And you're right, it looks like the OBC uses the odo to compute the instant MPG. So the actual speed/distance seems to be the biggest factor in computing the more accurate MPG in both manual and OBC MPG figures. HOWEVER, the amount of gas filled is very important, especially with a small tank like the Fit's. Even half a gallon will make a big difference. I'd rather trust the computer's direct link to the fuel injectors of how much fuel was actually being consumed.

And I'd like to ask how you KNOW that those calculations are "VERY accurate" and the calculator isn't lying to you right to your face? Please expound on how those figures were verified.

People still say this? Wow.

 

Exactly right. Although, the more samples you take, the curve should even out. However, the pitfall is the actual mileage driven. If you can verify that the speedo/odo is correct, then your margin of error will decrease.

 

I got 503kms on 37 Litres of gas. That 7.3L/100km. pretty good considering I drive the sh*t out of it!

 

I managed to put 5.6 gals into a 5 gal jerrycan the other day; I'm a little suspicious of the calibration of the gas pumps as well.
Moon

 

2009 sport AT, average is around 37mpg

 

The can is probably bigger than 5 gallons, to allow for headspace.

 

no matter what anyone says manual calculations will always
be more accurate than that BSM.
if you think going to different gas stations gives you
different X levels then fill it up all the way and find out.

fill it to the top. drive your tank to E and then fill to the
top again. then do your manual calculations.
this method will be most accurate than anything else.