Speed vs. MPG charts (post 'em if you got 'em)

[MetroMPG]

Know what? I remember you mentioning that trick after I first posted that graph. I mentioned it to my brother and he used it in his Ridgeline afterwards... until it was written off last year.

Now he's got a 5-speed manual, and I approve!

[ever_green]

Originally Posted by rh0

I warned you it was government data.

I've always thought the "M" shape to some of those lines is intriguing

The PDF says the Subi is a 2.2L 4 speed auto. The only manual trans is the Corsica. It also says the data is from combined road and dyno testing, so this may be perfect (or better) conditions.

I've been trying to make sense of the data from the 1.8L 4 speed Celica and the 1.6L 3 speed Prizm (very similar engines and Cd) and how/if it relates to my 1.6L 5 speed manual Corolla.

I have a subaru with a 4 speed auto and I will perform some odb2 datalogging tonight using romraider and post back results. In my experience mileage has always been lowest at 30 MPH (whenever i hit 4th gear). also this data loggin uses injector pulse width to calculate consumption, so it's accurate.

[ever_green]

after an hour of run after runs i managed to do a good log. Tempratures were a bit chilly at 45'f & light drizzle. here is the result.



ps. i also attached one of the datalogs.

[PRAVINS]

Originally Posted by bluejoey

Ever since I started lurking on Ecomodder (a few years ago), I've always been keen on the speed vs. mpg charts. Not only do they clearly show the influence of speed on mileage, they also provide a handy reference for people who don't yet have instrumentation, or folks interested in the efficiency slopes of other vehicles. I've searched and haven't found any collections of charts here, so I'm hoping this might become a place to store these charts as a reference. To kick things off, here are a few I've found from users here:

NOTE from admin: if you add a graph, PLEASE also include a link to the source site/page. Thanks!

2006 Toyota Corolla 1.6L Auto by MetroMPG
from http://ecomodder.com/forum/showthrea...atic-6710.html



1998 Pontiac Firefly / Geo Metro 1.0L Manual by MetroMPG
from Speed kills: testing MPH vs. MPG in top gear - MetroMPG.com



2002 Nissan SE-R, 2006 Scion, Elantra by SentraSE-R



Assorted cars by Auto Bild Magazine
from Speed kills: testing MPH vs. MPG in top gear - MetroMPG.com



If you have any more, please post them. If you have an instrument (SGII, Ultragauge, etc) and are willing to compare your speed to mpg at a variety of speeds, that would also be appreciated. I would be happy to make charts for anyone who supplies me with a range of figures.

Graph shown above, shows MPG in different gears & at various speeds when vehicle is operated at constant speed, on level road, with absolutely no braking.

At higher speeds there is drop in mileage due to increase in air resistance which is proportional to square of vehicle speed.

In lower gears, fuel consumption due to engine friction gets multiplied by gear ratio, hence mileage is low. Further in the same gear with increase in vehicle speed there is proportionate increase in engine r.p.m. & increase in fuel consumption due to engine friction is more than proportionate.

From the graph we can see the difference in MPG in different gears for the same vehicle speed.
e.g. at 40 miles/hr –
in top gear – MPG – 62
in 4th gear – MPG - 55 only.

In city traffic when we are compelled to drive at lower speeds, if we use higher possible gear we get better mileage. But if we operate in lower gear, MPG is very low.
e.g. at 25 miles/hr –
in 3rd gear - MPG - 60
in 2nd gear - MPG - 40.
You can see that at lower speeds drop in MPG is much wider as compared to difference in 4th gear & top gear.
data source : book ‘Improve Fuel Average (MPG/KMPL)’


PRAVINS

[Baltothewolf]

I wish I could find these charts for my '91 Ford Mustang LX. I am driving that to work instead of the insights due to me not being able to use my laptop in the insight, nor lay down and sleep in the back haha. Would like to know which MPH is the most efficient in time/fuel consumed ratio.

[basjoos]

Its easy enough to make a speed vs. mpg chart for your car. All it just takes is a flat, lightly travelled road at least 4 miles long and an hour or two of time to make a couple of runs in each direction at each speed.

[Baltothewolf]

Originally Posted by basjoos

Its easy enough to make a speed vs. mpg chart for your car. All it just takes is a flat, lightly travelled road at least 4 miles long and an hour or two of time to make a couple of runs in each direction at each speed.

I have no way of monitoring mpg :P.

[PRAVINS]

Originally Posted by Baltothewolf

I wish I could find these charts for my '91 Ford Mustang LX. I am driving that to work instead of the insights due to me not being able to use my laptop in the insight, nor lay down and sleep in the back haha. Would like to know which MPH is the most efficient in time/fuel consumed ratio.

My rough estimate for '91 Ford Mustand LX' indicate that you can get best MPG, in the speed range of 30 to 40 MPH in 3rd gear. (assuming that it is 4 speed automatic transmission).

In fact, the pattern of graph I have posted will be similar for all models except for the change in values.

Normally, we get best mileage at lowest possible speed in top gear. In this case 4th gear is actually an overdrive with min. speed of around 50 mph.

Since you are driving in city, vehicle speed is decided by traffic on the road.
In such case, it always economical to drive in highest possible gear for that speed. In other words we should drive in lower engine r.p.m. range. for getting best possible MPG.

PRAVINS

[Baltothewolf]

Originally Posted by PRAVINS

My rough estimate for '91 Ford Mustand LX' indicate that you can get best MPG, in the speed range of 30 to 40 MPH in 3rd gear. (assuming that it is 4 speed automatic transmission).

In fact, the pattern of graph I have posted will be similar for all models except for the change in values.

Normally, we get best mileage at lowest possible speed in top gear. In this case 4th gear is actually an overdrive with min. speed of around 50 mph.

Since you are driving in city, vehicle speed is decided by traffic on the road.
In such case, it always economical to drive in highest possible gear for that speed. In other words we should drive in lower engine r.p.m. range. for getting best possible MPG.

PRAVINS

I drive highway at night, and early morning so traffic is never an issue for me. It's only a ~5.5-6.3 mile trip from work to home, with about 4.7-5.5 being at cruising speed. I have 2 different posts (I work security) hence the mileage difference. I don't want to take 20-25 mins getting home at 35mph lol. I'm just trying to figure out of the fuel burned at 65mph is worth the time I save over 55mph. I read all the time that people with 331 stroker kits, and 3.73 rear ends can still get 27mpg at 65mph so yea.

[Edit]: I have the 302 with 2.73's. I will be swapping in 3.73's eventually.

[MetroMPG]

Posting this now that I got the ScanGauge calibrated and revised the numbers from this thread:

http://ecomodder.com/forum/showthrea...7-a-30111.html

Showing both the baseline & modded speed vs. fuel economy for this Civic...

2007 Civic LX sedan 5MT (34 EPA hwy)