Do you get about 4 MPG less during winter ? - Page 2 - Toyota Yaris Forums

TheSilkySmooth · 05-18-2009, 10:47 AM

Quote:

Originally Posted by 07WYarisRS

. ... Even at idle when the engine is warm, the engine still uses a lot more fuel when air temps are cold because of the much higher oxygen levels.

If you have higher oxygen contenet at given throttle opening, then ECU add fuel to compensate, then you have more heat energy, then the engine idles faster, then the ecu closes the throttle some to lower RPS count. This reduces air flow and reduces fuel utilized. and you are back to stasis.

thebarber · 05-16-2009, 12:00 AM

winter is more about different gas, warm up times and all the fluids in/around the engine being cold and thick when you start the car....

i run about 5mpg less in winter....but the only 2 winters ive had the car were in eastern canada where it could be -20C for long stretches and i was doing relatively short in-city trips all the time...though i never let the car warm up TOO much before driving it....

GeneW · 05-16-2009, 12:24 PM

I've seen this effect, especially with very cold and very hot days. I get my best mileage above 85 fahrenheit.

A heat engine's efficiency improves with greater temperature difference between the "hot" and "cool" side. Unless that block is dropping below normal operating temps I don't see any advantage to blocking off the radiator. The radiator uses a thermostat to regulate block temps anyhow.

My take on it is to use waste heat to heat inlet air. Could be done, probably painlessly, by figuring out how much air the motor draws in, and then estimating how much viscous drag a normal heating core puts on the inlet air. Blend air streams until you get a decent compromise on temps and inlet air drag.

Gene

daf62757 · 05-16-2009, 01:10 PM

Here in Indiana, it can get really cold and the mileage on my Yaris goes down in cold weather. But warm weather brings about a paradox. You getter about the same mileage because you have your AC on. After reading all these stories...accounts...online about 50 miles per gallon, I have come to the conclusion that they are the exception and not the rule. About 40 MPG...give or take a few...is what you will get with the Yaris if you drive normal, don't speed, drive with the right air pressure, and not add on costly air breathers.

I am hoping the next generation Yaris will get 50 MPG because no matter how new my Yaris is, it is really old technology \.

Yaris Hilton · 05-16-2009, 11:06 PM

I filled mine today and got 39.8 MPG on alcoholic gas. That was with a bit more highway driving than usual in the mix, but mostly in town. I've been running the AC more lately, too. I'm quite happy with it in any case.

anonymous user · 05-17-2009, 06:44 AM

If i could add my 2cents as well.....
Although I live in Hawaii, daytime temps change maybe 10-18 degrees between summer and winter. Nights can get into the low 50's, but usually 58-60's in winter. That being said, i believe summer and winter gas changes about 4-5 mpg, atleast to my gas logs. 34-35 mpg in winter, 38-40 in summer.

41magmag41 · 05-17-2009, 01:32 PM

I get about 35 in the winter and 42 or so in the summer. I have a 25 mile commute to work. With the colder air in the winter the engine takes longer to heat up thus a more fuel, in the summer It takes about 1/2 mile for the engine to be at operating temp thus better mileage. normal for any car.

05-16-2009, 12:00 AM	#2
thebarber daily driver View User's Garage Drives: the #wrecho Join Date: Jun 2006 Location: Grand Rapids, MI Posts: 5,877	winter is more about different gas, warm up times and all the fluids in/around the engine being cold and thick when you start the car.... i run about 5mpg less in winter....but the only 2 winters ive had the car were in eastern canada where it could be -20C for long stretches and i was doing relatively short in-city trips all the time...though i never let the car warm up TOO much before driving it.... __________________

05-16-2009, 01:10 PM	#4
daf62757 Nothing beats a Toyota! View User's Garage Drives: 2013 Yaris 5 dr liftback Join Date: Jan 2009 Location: Indianapolis, Indiana Posts: 564	Here in Indiana, it can get really cold and the mileage on my Yaris goes down in cold weather. But warm weather brings about a paradox. You getter about the same mileage because you have your AC on. After reading all these stories...accounts...online about 50 miles per gallon, I have come to the conclusion that they are the exception and not the rule. About 40 MPG...give or take a few...is what you will get with the Yaris if you drive normal, don't speed, drive with the right air pressure, and not add on costly air breathers. I am hoping the next generation Yaris will get 50 MPG because no matter how new my Yaris is, it is really old technology \. __________________ Big Dave Indianapolis, IN Synthetic Oil....its in my car.....for at least 10,000 miles!

05-17-2009, 06:44 AM	#6
anonymous user rarer than JDM -1 of 1! View User's Garage Drives: 07yaris Join Date: Oct 2008 Location: windward oahu Posts: 402	If i could add my 2cents as well..... Although I live in Hawaii, daytime temps change maybe 10-18 degrees between summer and winter. Nights can get into the low 50's, but usually 58-60's in winter. That being said, i believe summer and winter gas changes about 4-5 mpg, atleast to my gas logs. 34-35 mpg in winter, 38-40 in summer. __________________ It's not what you drive, or how much $$ you throw at the car. Mod the ballast on the front left first!

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05-16-2009, 12:24 PM	#3
GeneW Banned Drives: 2008 Yaris Join Date: Oct 2008 Location: Pennsylvania Posts: 1,034	I've seen this effect, especially with very cold and very hot days. I get my best mileage above 85 fahrenheit. A heat engine's efficiency improves with greater temperature difference between the "hot" and "cool" side. Unless that block is dropping below normal operating temps I don't see any advantage to blocking off the radiator. The radiator uses a thermostat to regulate block temps anyhow. My take on it is to use waste heat to heat inlet air. Could be done, probably painlessly, by figuring out how much air the motor draws in, and then estimating how much viscous drag a normal heating core puts on the inlet air. Blend air streams until you get a decent compromise on temps and inlet air drag. Gene

05-16-2009, 11:06 PM	#5
Yaris Hilton Half a Bubble Off Plumb Drives: 2009 Yaris Sedan Join Date: Mar 2009 Location: Bristol, Tennessee, USA Posts: 1,593	I filled mine today and got 39.8 MPG on alcoholic gas. That was with a bit more highway driving than usual in the mix, but mostly in town. I've been running the AC more lately, too. I'm quite happy with it in any case.

05-17-2009, 01:32 PM	#7
41magmag41 Drives: Loaded 2007 mica silver sedan Join Date: Sep 2007 Location: New hampshire Posts: 226	I get about 35 in the winter and 42 or so in the summer. I have a 25 mile commute to work. With the colder air in the winter the engine takes longer to heat up thus a more fuel, in the summer It takes about 1/2 mile for the engine to be at operating temp thus better mileage. normal for any car.