MPG City Or Country?

For those who don't know, MPG stands for miles per gallon.

So there is one thing I don't get about it though. When i see a car being advertised on TV, sometimes it will say something like 35mpg in the country and 44mpg in city.

I've always wondered how can that be? That is to say, how can there be a different rate of fuel usage in the country as opposed to driving in the city. Shouldn't it be the same mpg regardless of where you drive? Is there some sort of conspiracy to sell more gas by having the engine or some sort of hush hush technology that somehow automatically detects that you are driving in the city or the country and somehow changes how much gas is used?

So how does this happen?

reply to post by EvilSadamClone

I think they adjust the figures to reflect the more "stop-start" nature of city driving when compared to motorways or small towns. Things like traffic lights, other traffic, etc all slow the journey down. Hope it helps.

reply to post by EvilSadamClone


It's not country/city, it's city/highway.

You get better MPG on the highway because you aren't constantly stopping and accelerating. Stop and go traffic is bad for fuel efficiency, obviously.

reply to post by TinkerHaus


Well then, if you got better mileage on the highway, wouldn't the numbers reflect that and be higher than in the city?

Originally posted by EvilSadamClone
reply to post by TinkerHaus

 

Well then, if you got better mileage on the highway, wouldn't the numbers reflect that and be higher than in the city?

They are. You're thinking backwards. Highway mileage is always higher than city mileage (like here, for example).

FYI - 55mph is generally about the best speed for maximum fuel efficiency. Go over that and watch your MPG start dropping significantly.

The best fuel economy is usually around 50-55mph for a regular sized vehicle.

Originally posted by satron
The best fuel economy is usually around 50-55mph for a regular sized vehicle.

This is true.. I got a new crossover recently that advertises 28mpg highway, but if I'm going around 55-60 on a flat road, I can get it up to over 34mpg.

I average higher than advertised with city driving too. Driving habits play a large part in fuel efficiency. =D

Yup, correct MPG is always higher on the highway/motorway.

Cruise control, if you have it on your car, can also be a great help, especially at the 55mph speed some have already mentioned.

On average, I get about 28mpg around town in my car...
on the highway, i usually get around 46mpg.

There was one day I was doing a cruise control run for about 60 miles. I reset my cars computer to see what mileage I was getting (reset before I set off from start point.
Got to where I was going and checked my readings... I was rather nicely stunned...

56MPG

What car have I got?

A 1991 SAAB 9000 2.3 ltr. 16 valve
and here it is;

New is not always better

reply to post by EvilSadamClone

On the Highway, the car's engine is running at a sustained speed, or RPM,
(revolutions per minute) and temperature, it always gets better mileage as opposed to City driving, where the same engine is involved in stop and go traffic constantly, the engine temperature is higher, and as you can see, there is a real difference here. So, according to law, the car companies have to inform you of both. And another thing. The Factory default setting of the ECM are for maximum flow of gasoline. The companies do this so the car will start easily in cold weather, and not die at idle, and less tuning is involved. So, you waster gas. But! You can help that situation, and actually be able to turn down the gasoline flow from your dash! Interested?
Here is is:

This is a MAF/MAP Sensor Enhancer, and is wired into the sensor....it controls the voltage gong to the fuel injectors, and I have discovered I can turn down the flow by 15% and still run rich enough to not burn the spark plugs, or harm the engine. At $35, it's a steal. I have been running this device for three years now without a single problem.

reply to post by autowrench


autowrench, thanks for that link. I'm going to definitely take a look into your device - I love saving fuel/money.

Have you had any experience with the hydrogen chambers that allegedly can increase your fuel efficiency by up to 50%?

There are driving techniques that can also dramatically improve your gas mileage. Google on "pulse driving" for example. Back when gas was going through the roof, I adopted these techniques, and now, it's just second nature to drive this way. Sometimes, it's even fun to see how far I can get without pressing the gas, just using my current momentum.

The stop and start of heavy traffic or city driving is a killer to gas mileage. That's why if you can map out a route using mostly highway, even if a longer distance, you can often get better mileage and actually use less gas, even though driving a little further. Have to do the math though, and be able to tell what you're getting.

I commute and hour each way, every weekday, so as you can imagine, saving on gas is paramount to me, as it's really money in my pocket.

Just been for a 50MPH burn up the A38 to do a mini road test..

It's a lovely day, sun is shining, roads are dry. Temperature is around 19 degrees with a fresh wind.
reset my on board trip computer and set off..


And carried on.. trip computer is still working out averages etc.. BTW, I am using cruise control to sit at approx. 50MPH

46MPG @50MPH


So, I hit 50 to the gallon and thought "that'll do pig, that'll do"

Remember, my car is a 1991 Saab 9000 2.3 ltr.

Here's a few tips I know, and some I dont.. and some I wont use as they're ilegal.. Read and use at your own discretion, but I'm asure you're all sensible enough to know which ones are not quite legit.
howto.wired.com...
Adding acetone to fuel = more mpg
finaly;
www.getrichslowly.org...
I'm sure you'll find loads more similar pages out there with very similar tips, and even some not found here..
I am yet to try out the acetone one.. known about it for a while.

Safe and happy driving all...

As others have mentioned, running at a sustained speed instead of all the stop-start of city driving saves gas. Another positive about highway driving, is the pavement is usually in better condition, which means less resistance. This contributes such a small amount of increased mileage it would probably be hard to measure though. It's also possible the drafting effect might increase your mileage somewhat assuming the traffic is thick enough to keep the air moving in the forward direction, but not so thick you have to break and accelerate often.

A couple things,

Cruise Control actually uses MORE gas. Keep your foot on the gas to maintain steady speed and that's the best you'll get. Cruise control uses more gas because of the specific way it manages to keep your car at a specific speed.

The LED readouts of MPG in your cars dash are not very accurate, at all. While the overall mileage might be close to your average mpg reading, specific "at the moment" mpg readouts are lacking when it comes to accuracy. More of a guess on the computer's behalf.

In a truck, driving with the tailgate down hurts MPG

Opening all your windows instead of using the AC hurts your MPG

Giant rims hurt your MPG

Just thought I'd throw that out there.

But no, no conspiracy to force the car to use more gas in city driving. Other than simple logic, I also have hands on proof, because of the cars I've had with hand-built from the ground up motors, with no computers, still did better on the highway than the city.

Except of course the one that had a 3-speed and crazy gears in the rear end. Oh my how that hurts your mileage traveling at highway speeds.

Originally posted by TinkerHaus
reply to post by autowrench

 

autowrench, thanks for that link. I'm going to definitely take a look into your device - I love saving fuel/money.

Have you had any experience with the hydrogen chambers that allegedly can increase your fuel efficiency by up to 50%?

Yes, right now I am running two Jar Type generators on my G-20 V-8 Chevy Van for over two years now. We are currently saving near 30% of our gasoline consumption when the weather is right, damp and wet is best. This is stone age technology in the HHO world, and I am currently building a 19 plate 316L Dry Cell Design Reactor.
316L Stainless plates: 19
Gaskets: 20
Cell Surface Area: 228"
Performance: .75 Liters Per Minute at 10 Amps, and 2.5 LPM at 30 Amps. Plate Arrangement is: +NNNNN-NNNNN+NNNNN- (2 Full Series of Pos/Neg for automotive voltages) with Pulse Width Modulator.
Here is a video of one of these working...

Here is a video showing a sped up construction of one of these...

I am familiar with the technology, yes.

ACES IV is some good stuff, I've been using it for a couple of years now. Easily pulling 30+ mpg in my V8 Charger...