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View Full Version : How I got an extra 25 miles for basically free


soldout
04-27-2019, 11:59 AM
The other day I was watching a video by Chrisfix and he was explaining how important it is to change out the air in your tires from Winter to Summer air. Now I know this might sound crazy but he goes into detail in his video which I will link below. Basically Winter or colder air is denser and weighs more then Summer or warm air. Changing out the air in your tires will make your tires lighter and you will get better fuel economy.

So I let all the air out of my tires and refilled them on a day it was maybe 65F and filled them to 35PSI or 3lbs over recommended pressure. I also have a KNN air filter which I cleaned and reoiled.

Ive driven my Yaris for almost 180000 miles and I always lose the first gas bar around the 80 mile mark. After I did this experiment I have seen the first gas bar well over the 100 mile mark. This is highway cruising at 65mph with the cruise control, no special driving to maximize MPGs just cruise control.

Now the first picture is showing the 1st gas bar at 100 miles. The second picture is right after the 1st gas bar went away.

If you live in warmer climates this change in tire air temperature might not get you the same results as mine. If anyone tries this come back and post your results in this thread. I hope this saves you guys a lot of money and I wish I would have done this trick with the air a lot sooner.

https://www.youtube.com/watch?v=2t09qfrYwok

Jeanseb29
04-27-2019, 12:14 PM
I just watched his video (Christfix) on how to replace the muffler bearing. That awful fart muffler sound will finally be fixed on my yaris. Hope I'm gonna get better mileage also.
You should all check your muffler bearing. https://www.youtube.com/watch?v=eWdqlpxRA4I

tmontague
04-27-2019, 01:18 PM
Ya his videos are great, I replaced my piston springs this winter so I have a higher compression engine for track season. So far so good, really noticable difference!

NYC-SE
04-27-2019, 02:24 PM
Um.. guys April 1st was 4 weeks ago. Check your calendars (and your blinker fluid).

IllusionX
04-27-2019, 04:38 PM
Oh yeah, you happen to have filled with ethanol free fuel as well.

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soldout
04-27-2019, 05:09 PM
So you guys are shitting on this theory? Im not saying to go out and buy cans of Summer air but maybe try this for yourself and see if it makes a difference. It wont cost you anything but maybe 20 minutes of you time. Theres a reason why hot air ballons float into the sky.

http://www.weatherdudes.com/facts_display.php?fact_id=51

IllusionX
04-27-2019, 05:14 PM
Air in your tire heats up as you drive, or when sun shines on your tire. That's why air pressure in your tire always changes.

After a winter, you just need to adjust your tire pressure as weather warms up.

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soldout
04-27-2019, 05:41 PM
I understand that but what about the temperature of the initial fill of the tire. The cooler air is denser/more packed together and would take more of it to fill the same amount of space. The warmer air is less dense and would be able to fill the same amount of space requiring less of it. Once the air is in the tire it will expand or contract depending on the ambient temperature or tire temperature. Is this correct or a load of BS.

IllusionX
04-27-2019, 05:59 PM
Density will change inside the tire as air temp changes. That's why you tire pressure is greater when it's hot outside, and would "deflate" itself when ambient temp drops.
Not when you fill up

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tmontague
04-27-2019, 09:55 PM
So you guys are shitting on this theory? Im not saying to go out and buy cans of Summer air but maybe try this for yourself and see if it makes a difference. It wont cost you anything but maybe 20 minutes of you time. Theres a reason why hot air ballons float into the sky.

http://www.weatherdudes.com/facts_display.php?fact_id=51

I understand that but what about the temperature of the initial fill of the tire. The cooler air is denser/more packed together and would take more of it to fill the same amount of space. The warmer air is less dense and would be able to fill the same amount of space requiring less of it. Once the air is in the tire it will expand or contract depending on the ambient temperature or tire temperature. Is this correct or a load of BS.

Density will change inside the tire as air temp changes. That's why you tire pressure is greater when it's hot outside, and would "deflate" itself when ambient temp drops.
Not when you fill up

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:iono: I still am not sure if the OP is really trying to stretch an April fools joke out into the end of April or if he is seriously contemplating efficacy of this

What IllusionX stated is true. Yes, air that is warmer increases pressure and is less dense but only so in a closed system. Aviation deals with this due to the atmosphere being an open system. Care tires are sealed and therefore a closed system so density becomes dependant on pressure. Temp and density is a moot point, pressure is what matters and what you change as it is dependant on ambient temps and tire temps from driving.

Hot air balloons and tires are apples to oranges. By that rational I should add a wing to my car so it can achieve life and there become an airplane car...clearly not how it works in the real world. There are a ton of engineering videos online and articles to read on the topic, go nuts

dogsridewith
04-28-2019, 09:00 AM
:iono: I still am not sure if the OP is really trying to stretch an April fools joke out into the end of April or if he is seriously contemplating efficacy of this

What IllusionX stated is true. Yes, air that is warmer increases pressure and is less dense but only so in a closed system. Aviation deals with this due to the atmosphere being an open system. Care tires are sealed and therefore a closed system so density becomes dependant on pressure. Temp and density is a moot point, pressure is what matters and what you change as it is dependant on ambient temps and tire temps from driving.

Hot air balloons and tires are apples to oranges. By that rational I should add a wing to my car so it can achieve life and there become an airplane car...clearly not how it works in the real world. There are a ton of engineering videos online and articles to read on the topic, go nutsNot exactly. For a temperature rise, pressure increases and density is unchanged because mass and volume stay the same with the closed system.

tmontague
04-28-2019, 10:06 AM
Yes, which is what I was stating. Aviation deals with atmosphere where air can become less dense due to there being no restrictions like in a closed system

dogsridewith
04-28-2019, 10:22 AM
Density will change inside the tire as air temp changes. That's why you tire pressure is greater when it's hot outside, and would "deflate" itself when ambient temp drops.
Not when you fill up

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Not exactly. For a temperature rise, pressure increases and density is unchanged because mass and volume stay the same with the closed system.