Hot weather and poor economy

[cRiPpLe_rOoStEr]

Originally Posted by ProDigit

Some say it works well, others say that with engine blow by, the water molecules get stuck in the oil and becomes like a gel, rather than fluid oil.

Then, some others say that the engine will be hot enough to just steam out the water, which I believe will happen at highway speeds.

Steaming out the water is more likely to happen than contaminating the oil through the blow-by oily vapors, plus the suction at the intake stroke will drag it all to the cylinders at once. In the end, maybe the higher amount of moisture can prevent the oily vapors from coking inside the combustion chamber.

The bigger issue is that AC drain hose contains bacteria, algae and fungus. Overall it's so little that it will just burn up and form carbon, that gets blown out of the tailpipe at higher speeds.
However, occasionally there are fungus parts that will come loose from the hoses, and may actually be too large to burn up, and can potentially cause engine damage. So a filter, like a gasoline filter, is needed.
Not much is known to how frequently that filter needs replacement.

It's always good to have a filter for any fluid that would go inside an engine anyway...

Also, this won't work on turbo engines, as the turbo blades get worn out cutting drops and even water vapor!
If you can inject the water right before the intake manifold, behind the intercooler, it might actually work quite well on turbo cars.

Most water injection applications I'm aware of were done to forced-induction engines, so it's a safe bet.

Aside from cooling effect, adding water in your air intake adds very little to the performance. Even in USA, Chevron is known to have crappy gas (too much Ethanol), which contains a lot of water. You can often see when a car has Chevron gas, by looking at the tailpipe when he departs from a stop.
Some have what looks like 'waterfalls' coming out of their pipes!

Some small amount of moisture actually leads to an increase to the anti-knock properties of the gasoline. I'm just not sure which is the limit. But a supplemental water injection is not the same as contaminating the gasoline with an excessive amount of moisture.

[Mustang Dave]

My Mustang gets its best fuel economy during the Summer months. Low air density (due to elevated temperatures and 6500+ ' elevation) and Summer fuel. And I rarely use A/C since ambient temperature rarely exceeds 80's in the Summer. This is in a part of Arizona that few people know.

[Ecky]

My car gets is best economy in summer too, so long as I don't have a passenger. I never run A/C for myself.

Originally Posted by ProDigit

The smaller the engine, or the bigger the ac system, the more the mpg drop.
My previous 150hp mid size sedan car had an average of 10% less mpg.
My current 200HP hot hatch car, the mpg drop from the AC is negligible

I'd say this is probably *mostly* a flaw inherent in the metric of MPG itself.

Let's say hypothetically that running an A/C compressor needs 0.5L / 100km average fuel to burn. In a truck getting 15mpg (15.7L/100km) that's only a drop to 14.5mpg (16.2L/100km). In my Insight getting 90mpg (2.6L/100km), it's a drop to 75mpg (3.1L/100km).

[ProDigit]

Originally Posted by Mustang Dave

My Mustang gets its best fuel economy during the Summer months. Low air density (due to elevated temperatures and 6500+ ' elevation) and Summer fuel. And I rarely use A/C since ambient temperature rarely exceeds 80's in the Summer. This is in a part of Arizona that few people know.

Your summers, are our winters. Wait until it starts getting over 110-115F. 100+F on turbo cars is wrecking havoc with the performance.

[19bonestock88]

I remember my Ion Redline didn’t do that great when it was hot outside either... above 85* outside and it pulled timing and generally felt like a dog... on a cool, 65* evening it was a savage, when it ran full boost and timing... of course it wasn’t stock and the additional boost made lots of extra heat

[Piotrsko]

Got to look at intake temps. Your obd system does. Get it warm enough, and your turbo boost becomes worthless due to "density altitude"

Even if you were flooding the crankcase with water, block temps should be above ambient boiling point.

Water injection usually contains alcohol.

[cRiPpLe_rOoStEr]

Originally Posted by Piotrsko

Water injection usually contains alcohol.

More specifically methanol, as high as 50%, to prevent freezing but it also eases the vaporizing.