SameerP

heat is not an issue as much...my car has felt very strong on dry days in the 90's...but for instance last two days here in Chicago have had about 88% humidity, temps have been 80-85 degrees...car feels sluggish as all hell.

Talked to a colleague with a TT 225, he said his car felt sluggish...as well as another A4 owner.

What is it about high humidity?

Cheers,
Sameer

nospek3

.

paul_858

reducing the efficiency of the fuel

SameerP

Makes sense, what about the idea more water in the air has a cooling effect on intake temps though?

James R.

The cooling that it brings ain't worth the O2 it displaces.

paul_858

Keep in mind that if the air is 80* and humidity is 90%, the air is still 80*. However, when enough water is introduced into the intake tract then the air can be sufficiently cooled... injecting water pre-turbo has minimal effects since the turbo is so hot it vaporizes the water too quickly. When the water is introduced post charge, it evaporates cooling the air more efficiently than pre-charged air

SameerP

Also, does this have the same impact to NA cars, or is the result magnified on FI cars because they rely more on forcing more air, and less on displacement (generally of course) ?

Cheers,
Sameer

paul_858

same boost levels, less o2

James R.

best driving weather is cold as hell with low humidity...air is dense, cool and dry. Everyone suffers in the hot and wet.

paul_858

mmm... car blow chunks... not exactly a good thing to think about in a turbo'd car =P