Does high humidity climates effect/worsen FE?

[Chris D.]

I was curious if this has something to do with it..

My FE hasn't been where it usually was when I was in California (Minnesota now)

any incite?

[SVOboy]

I've heard people talk about getting better FE right after a light rain, but that's just conjecture and even so, what it really means, I don't know.

[Ford Man]

Originally Posted by Chris D.

I was curious if this has something to do with it..

My FE hasn't been where it usually was when I was in California (Minnesota now)

any incite?

I've never tried it, but there are claims water injection helps FE if this is true I would think that a more moist air would also be of benefit. Cooler temperatures are another thing you are probably faced with in MN as aposed to CA and you always get better mileage in a warmer climate than in a cooler climate. I can usually tell a difference in FE when the outdoor temperature is in the 80's aposed to the mid to upper 90's.

[cfg83]

Chris D. -

Could it be the gas? Maybe you have a different formula.

Also, I keep thinking of the CAI/HAI example. If Cold-Air-Intake is bringing in colder air, isn't it considered to be more "dense" with moisture?!?!? With the Hot-Air-Intake, the idea is that the air is drier, aka less oxygen, so it's running leaner.

CarloSW2

[basjoos]

High humidity improves mileage since water vapor has a lower density than nitrogen, oxygen, or CO2, so high humidity reduces aero drag. It also de-rates the engine's power since the water molecules displace some of the oxygen that the engine could be sucking into the cylinders, so the ICE burns less fuel, also improving mileage.

[TestDrive]

Things that changed with the move from CA to MN

• Gas Blend
• Elevation (overall and variations along your commute)
• Humidity
• Average Temperature

[Chris D.]

hmmm good info..

as for elevation, its about the same as Modesto CA, or not too far off to change anything..

fuel grade and temps defiantly have something to do with it..
I'm going to have to look into a grill block now to get some FE back.

Also I have a nagging suspicion that my plugs are in dire need of replacement..(been a while)
I need to read those and see how thats rollin..

[RH77]

Originally Posted by basjoos

High humidity improves mileage since water vapor has a lower density than nitrogen, oxygen, or CO2, so high humidity reduces aero drag. It also de-rates the engine's power since the water molecules displace some of the oxygen that the engine could be sucking into the cylinders, so the ICE burns less fuel, also improving mileage.

Cool, humid days seem to offer the best FE -- especially in the morning hours (even with the warm-air intake).

The Physics makes sense.

RH77

[tasdrouille]

There are 2 papers on atmospheric conditions impact on ice efficiency in the sticky in the general efficiency forum. According to those papers humidity reduces bsfc.

[PaleMelanesian]

My own records show a 6% improvement in humid weather vs dry. That's collected over a year and a half, on my daily commute.