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weather and engines...?

1053 Views 6 Replies 6 Participants Last post by  meebs
Ok sometimes I over analize stuff, but now this has been circling in my head for 20 minutes and I need help. :biggest:

We all know that cooler/denser air is better for engines as you get more oxygen to burn.

Now what is confusing me is the weather. When a high pressure system moves in, it is generally warmer and drier. The barometer reading goes up, there is more pressure.

When a low pressure system moves in, it is generally cooler thus denser, but wet. When a low moves in the barometer goes down. Less air pressure.

So would a high pressure system be better for an engine, since there would be more air pressure? But in a low pressure system, the air is cooler and denser. So maybe it all just evens out??? Damn you relativity!! Damn you!!!:nuetron:

Here's a snippet from how stuff on pressure,

A barometer measures air pressure: A "rising" barometer indicates increasing air pressure; a "falling" barometer indicates decreasing air pressure.

In space, there is a nearly complete vacuum so the air pressure is zero. On Earth, because there are many miles of air molecules stacked up and exerting pressure due to the force of gravity, the pressure is about 14.7 pounds per square inch at sea level (see this page for a good explanation of atmospheric pressure).

The interesting thing about air pressure is that it is different at different points on the planet and it changes over time. Why might that be? If you've read How Hot Air Balloons Work, you know that hot air is less dense (lighter) than cooler air. Therefore, on any given day you would expect the air over a desert to have a lower pressure than the air over an ice cap. And that would be true. These same sort of pressure differences occur all over the planet for various reasons.
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Too much time to think...:stupid:

Well ,there's no doubt that Subies love the cold weather,dryer the better it seems to me.Its winter here now and my car's lovin it.
jagcars26 said:
Well ,there's no doubt that Subies love the cold weather,dryer the better it seems to me.Its winter here now and my car's lovin it.
You sure its not the new cam? :D
colder air is denser, more O2 molecules, more power in combustion...air pressure (as in barometric) has really no effect on motors...correct me if I am mistaken...
Baro pressure has almost no effect on performance. The engine can only pull in so much air by volume, and the difference between low atmoshpheric pressure and high is very small. The real difference occurs in temp, then the air gets more dense as it cools, and the same volume of air has more O2 molecules to burn.
thanks for the replies. That's what i should have asked, "does baro affect performance?" :p

again, thanks. :biggest:
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