Does the weather(cold/dry vs. hot/humid) effect the performance of the car?More horsepower in cold weather?any info?

 

Yes weather conditions impact engine performance. The more dense the air, the more hp the engine will produce. Higher air density = colder air or dryer less humid air or higher barometric pressure or lower altitude. An engine in Death Valley (lowest altitude) in freezing temps with 0% humidity and a high pressure system overhead will put out more hp than the same engine in Denver (high alt) in 100F heat while it's raining (100% humidity) from a hurricane outside (low pressure).

 

Yes, cold air helps the engine make more power.

On the down side, cold air (denser, more viscous) requires more power for the car to push through it. As an extreme, think of driving a car submerged in molasses. And of course, colder oil and grease in the drivetrain require more power, too. These are the things that result in poorer gas mileage in the winter.

 

I always thought it was the "winter blend gasoline" that caused lower gas mileage in winter.

 

I filled up, gone about 40miles and its allready at 3/4 a tank.

 

My gas mileage/performance was pretty shitty last time I was in a hurricane, in Denver.

 

OK, there's that, too.

 

more power with cold air..hence why I get my dynos done in the winter.

 

im in atl and when we got hit with the past few cold fronts my gas mileage SUCKED ASS it was god awful

 

Man, with such dramatic difference, we should be seeing more than 15 hp fluctuations!

Here is a direct quote from Sport Compact Performance by the Haynes manual's guys: "For every drop of 10-degrees F in the intake air fed to your engine, your power goes up about 1%".