Toasty-Stg3::HCBP

As it varies from region to region, what effect do you think it has on the performance of the car?

BTW, Alabama is a daily sauna.

FBAnder

says care is faster and more responsive at night with lower temps and lower humidity. I would assume heatsoak comes around more quickly in very humid conditions

DAP@EPL

can dramatically affect performance.

-Dave Pramanik

Ochlockonee

With more water in the air, is less thermal energy required to raise it's temp? If that is true then I could see how humid air would reduce an intercooler or radiator's effectiveness. But what if the opposite is true? Also cars are not cooled by heat lost in evaporation, like us, so I can see how it would make me hotter, but not my coolant or intake air temps.
Sorry for having so many questions, but I have heard over and over again how humidity slows you down, but I don't understand why, unless you are using intercooler misters.

DAP@EPL

Water is incompressible. Turbos function by compressing air. The more water in the air, the less it can be compressed, so the turbo efficiency is reduced.

-Dave Pramanik

sj6sp

Water in a gaseous state is compressible. The liquid state is where it essentially can't be compressed.

Now that I jumped on this thread...

Water vapor has a higher specific heat than other components of air which means temperature rises less given the same amount of energy input. Based on the same property, it still contains the same amount of heat energy when cooling is considered so this may be a wash (close anyway)

I do think that given the same IAT, humid air is less likely to detonate than dry air since it would not reach as high a peak temperature during engine compression.

Higher water content in air does slightly "dilute" the amount of the other components (oxygen). This dilution of Oxygen in my opinion has the biggest impact on perforance since realistically, it could push O2 content from say 21% in dry air to 20% in humid air. This is a significant amount (roughly 5%) of available oxygen for combustion. Got all that? Good, cuz I don't ;-)

M3iRiSH

I've read it's like having very high humidity, where the water absorbs more of the heat during the combustion cycle.

Toasty-Stg3::HCBP

That makes the most sense.

Ochlockonee

Latent heat of vaporization is what makes intercooler misters work. As a liquid evaporates, it absorbs a lot of heat to do so. I'm not sure what the correct phrase used to describe the heat released when a gas condenses, but latent heat of condensation sounds good enough to me. So as compressed, extremely hot, humid air exits the turbos and enters the intercoolers, one would think that a lot of thermal energy is put into the intercoolers simply to condense the water and not cool the air. I guess.