GM owners pay 50 per cent more for gas than expected

[GS8]

I was expecting old people when I clicked the link.

[Xu.Vi]

My GM consumes 15.2L/100KM on a 2.4L. So much for that 9.2L/100KM i'm suppose to be seeing

[Traum]

Originally Posted by Splinter

Cold weather gives you better fuel economy. The recent change in temperature would explain them getting better fuel economy than they had over the summer.

You've got that backwards, dude. Gas mileage in the winter should almost always be worse compared to the summer.

[GS8]

My Buick's fuel economy is 1.5L worse than advertised. I'm actually impressed because I lead foot the fuck out of it.

Blower whine

[Jmac]

While colder air increases combustion efficiency and reduces the rolling resistance of your tires, it's more than offset due to the higher concentrations of ethanol mixed into your fuel during the winter months.

Most vehicles will have worse fuel economy during the winter, although there are so many variables to take into account that it's possible to get better fuel economy (e.g. if you drive in a town that has heavy traffic during the summer, the decrease in traffic during the winter can lead to better fuel economy).

[Splinter]

Originally Posted by Traum

You've got that backwards, dude. Gas mileage in the winter should almost always be worse compared to the summer.

Can you explain that? It goes against everything I know about engines.

[46_valentinor]

suddenly the s2000 doesn't seem all that bad at approx 11/100km mixed city and highway.
i always thought you would get worst mileage in the winter because of the extra fuel used during start up and time it takes to get up to optimum engine temperature.

[Zedbra]

Originally Posted by Splinter

Can you explain that? It goes against everything I know about engines.

You should learn about Google. Type in: better gas mileage in winter? And the responses are: Better Gas Mileage in Summer than Winter, 9 reasons why your winter mileage sucks, etc.

[RRxtar]

gas has different mixtures in the summer and winter. winter gas contains more butane which contains less energy so you burn more

engines are made to run best at normal operating temp and burn more fuel when cold

even things as simple as oils are significantly thicker when they are cold (engine, tranny, difs, grease in bearings)

AC running when your windshield defroster is on

Simply having to push thru slush and snow


plus all the way smaller reasons like colder air being denser, dirty car having more air drag, etc

[Timpo]

this is exactly why we need kei cars here.

[Purely]

Originally Posted by Splinter

Cold weather gives you better fuel economy. The recent change in temperature would explain them getting better fuel economy than they had over the summer.

??????????

[Splinter]

Double posted

[Splinter]

Originally Posted by Zedbra

You should learn about Google. Type in: better gas mileage in winter? And the responses are: Better Gas Mileage in Summer than Winter, 9 reasons why your winter mileage sucks, etc.

Great, a bunch of people repeating stuff they heard from each other, same as what I'm seeing on here. That's why I asked, because I DID look on google and I couldn't find anything credible.

So you can stick your facepalm up your ass.

Also, google isn't 'ask jeeves'. You don't ask it questions.

Originally Posted by gYU

??????????

Modern fuel injected cars measure ambient air temperature. When temperature goes up, they increase the amount of fuel injected to richen the mixture and prevent detonation. So your car can run leaner in the cold.

That was my understanding, but I'm definitely open to hearing an explanation of why that might not be true.

Originally Posted by RRxtar

gas has different mixtures in the summer and winter. winter gas contains more butane which contains less energy so you burn more

engines are made to run best at normal operating temp and burn more fuel when cold

even things as simple as oils are significantly thicker when they are cold (engine, tranny, difs, grease in bearings)

AC running when your windshield defroster is on

Simply having to push thru slush and snow


plus all the way smaller reasons like colder air being denser, dirty car having more air drag, etc

They use less fuel when cold (after the initial startup)
Oil temperature rapidly gets up to normal temperature
AC runs in the summer too
It's not always snowing when its cold
Dirty cars have less drag (mythbusters!)

So except for the very short period of initial warmup, I still don't understand. Maybe if your average journey is only 10 minutes or something.

I think a more likely explanation is that people drive more slowly in the winter. It has nothing to do with the car at all.

[Zedbra]

[multicartual]

Originally Posted by ss6o4

My GM consumes 15.2L/100KM on a 2.4L. So much for that 9.2L/100KM i'm suppose to be seeing

I floored it everywhere in my 135i and I still managed 13.5L/100KM

[multicartual]

Originally Posted by RRxtar

gas has different mixtures in the summer and winter. winter gas contains more butane which contains less energy so you burn more

engines are made to run best at normal operating temp and burn more fuel when cold

even things as simple as oils are significantly thicker when they are cold (engine, tranny, difs, grease in bearings)

AC running when your windshield defroster is on

Simply having to push thru slush and snow


plus all the way smaller reasons like colder air being denser, dirty car having more air drag, etc

Anyone who owns a road bike can feel how much slower they ride when their tires are slightly deflated

[Traum]

Originally Posted by Splinter

Great, a bunch of people repeating stuff they heard from each other, same as what I'm seeing on here. That's why I asked, because I DID look on google and I couldn't find anything credible.

The common sense factors (as to why winter gas mileage is worse) would include:

- Longer idling during start up (to warm up the car)
- Engine oil is more viscous on cold starts in the winter months, takes longer to return to its standard operating viscosity, and cools off faster after engine shut downs. Thicker oil = higher engine internal resistance = burns more fuel
- greater electrical loads in the winter
- different summer vs winter gas formulations

I've been tracking my gas usage on the few different cars I've had for the better part of 10 years, and the winter fuel economy is always worse than the summer months. With my current DD beater, I typically get a low 7.x litres/100km, doing close to 600km per tank in the summer months. In the winter, that number jumps up to a high 7.x litres/100km, with the per tank distance going just over 500km per tank, so that's a good 10-13% difference. For what it is worth, I only minimally idle my car regardless of the time of the year as I prefer to just drive conservatively until the engine warms up.

I'm sure there are other more sophisticated explanations to the worse winter gas mileage mystery. But I'm just an average Joe with an average intelligence, so unfortunately I can't tell you what those sophisticated reasons might be.

[Gucci Mane]

Originally Posted by multicartual

I floored it everywhere in my 135i and I still managed 13.5L/100KM

thats pretty shitty for a little car. i can get that mileage from my big heavy v8 f150 if i drive like an old man. with my driving style i get 16L/100km.

[UFO]

Originally Posted by Jmac

My dad was considering a Dodge Dart as a commuter up until I showed him the EPA numbers (41 mpg highway) relative to Transport Canada (59 mpg highway).

It's fucking ridiculous how they can advertise these blatantly unrealistic numbers.

You also have to factor in imperial gallons vs. metric gallons. Imperial gallon is 3.8L, metric gallon is 4.5L.

Things are usually advertised in imperial gallons, but I've seen cases where metric gallon was used to get over the magical 50mpg

[46_valentinor]

Originally Posted by Splinter

They use less fuel when cold (after the initial startup)
Oil temperature rapidly gets up to normal temperature
AC runs in the summer too
It's not always snowing when its cold
Dirty cars have less drag (mythbusters!)

So except for the very short period of initial warmup, I still don't understand. Maybe if your average journey is only 10 minutes or something.

I think a more likely explanation is that people drive more slowly in the winter. It has nothing to do with the car at all.

dirty cars don't have less drag. myth busters found out that a GOLF ball car with dimples have less drag than a car with a conventional smooth surface.

oil temperature doesn't rapidly get up to normal temperature in the winter, especially when its really cold. it takes my car about 10 minutes for my temperature gauge to reach normal in the winter vs maybe 5 minutes in the summer and that is only my water/coolant not my oil temperature; for oil temperature you're looking at an additional 10-15 more minutes! so essentially, assuming its cold and around 0 degrees, you're taking about 20-30 minutes to get your car up to optimum running standard in the winter! plus, don't forget your transmission fluid, differential fluid, grease...etc all adds up to making the car less efficient as there are more drag until it gets warmed up as well.

[Jmac]

Originally Posted by UFO

You also have to factor in imperial gallons vs. metric gallons. Imperial gallon is 3.8L, metric gallon is 4.5L.

Things are usually advertised in imperial gallons, but I've seen cases where metric gallon was used to get over the magical 50mpg

The Metric measurements of volume are litres or cubic ____meters.

There is an imperial gallon, which is 4.546 litres and the US gallon, which is 3.785 litres.

That's also only a 20% difference, not a 44% difference.

[a00755836]

im not sure about now, but fuel consumption ratings get measured on a rolling road. so theres no wind resistance, or any traffic. if manufacturers do tests themselves, i bet they accelerate slower than james may.

[UFO]

Originally Posted by Jmac

The Metric measurements of volume are litres or cubic ____meters.

There is an imperial gallon, which is 4.546 litres and the US gallon, which is 3.785 litres.

That's also only a 20% difference, not a 44% difference.

Got my imperial/US/metric gallons mixed up, but you got my gist kind of.

I wasn't saying your Dart numbers were due to imperial vs. US gallon especially since fuel economy in Canada is officially reported in US gallons. But for marketing material, important to read the fine print.

[SkinnyPupp]

Assuming they work 9-5

Have to leave for work by 6:30.. that means wake up at 6:00 at the latest (if you skip breakfast and shower at night).. So if you want 8 hours of sleep, go to bed at 10:00

Get home at 7:30-8:00pm.. have dinner, take a shower, time for bed at 10:00

What a life!

[Lomac]

Anyone wanting to know how the Canadian tests are run, this is a good read:

http://oee.nrcan.gc.ca/sites/oee.nrc...guide-2011.pdf

I'll highlight a couple important parts, though:

The FTP is a standardized laboratory test method used in Canada that includes the use of standardized fuels, laboratories and testing equipment, test cycles and calculations. Selected test vehicles are “run in” for about 6000 km before testing.

A vehicle being tested is mounted on a two-wheel laboratory chassis dynamometer programmed to take into account the aerodynamic efficiency, weight and rolling resistance of the vehicle. A trained driver then runs it through simulated city and highway driving cycles.

All vehicles, including those with four-wheel (4X4) or all-wheel drive (AWD), are tested in two-wheel drive mode. However, tests are adjusted to reflect the increased weight and engine load using 4X4 and AWD systems.

The city test simulates a 12-km, stop-and-go trip with an average speed of 32 km/hour (km/h) and a top speed of 91 km/h. The test runs for 23 minutes and includes 18 stops. About four minutes of test time are spent idling, to represent waiting at traffic lights. The test begins from a cold engine start, which is similar to starting a vehicle after it has been parked overnight during the summer. When the test is completed, the test cycle starts again with a hot engine start, and the first eight minutes of the test are repeated. This simulates restarting a vehicle after it has been warmed up, driven and then stopped for a short time.

The highway test simulates a 16-km trip with an average speed of 77 km/h and a top speed of 97 km/h. The test runs for 13 minutes and does not include any stops. However, the speed varies to simulate different kinds of highway and rural roads. The test begins from a hot engine start

Yup. Sounds like real world tests to me.