So modern engines correct for temperature and altitude, but do

>>16671115
Bumping because I genuinely want to know the answer to this to.

>>16671115
No, you just figured out a major gap in combustible engine engineering. Get to your nearest Ivy league school today and get to work!

i wouldnt think so, i know the m4gts has water injection so presumably it ould to see how much humidity is in the air already
idk tho

>>16671115
They do in closed loop. Water reduces AFR and as a result you will see short term fuel trim.

At WOT there is no correction. Unless you're reaching dew point the compression stroke is going to be like 10x ambient temperature so what little water is in the air will be irrelevant.

>>16671182
Sorry I'm lost. Can you dumb that down a bit?

>>16671164
To have an appreciable effect on the engine water injection needs about 10% of the fuel injected.

For reference an R35 has 570cc injectors. 85% duty cycle for max throttle means 485cc injected so we need about 73cc of water per cylinder. At 100% relative humidity at 20C you get 17 cc of water per cubic meter of air. So over 6 cylinders you would need 25.65 cubic meters of air. Even at 1 atm of boost you wouldn't be able to fit anything near that.

Engineers far better than me have already done the calculations and run the tests. It's not enough of a factor.

>>16671188
When the car is operating in feedback control for fuel injection the presence of water will cause the oxygen sensor to read reduced oxygen as the water is taking up some of the exhaust rather than oxygen.

>>16671226
Ah okay. So if the engine doesn't have o2 sensors, it can't correct. But if it does, it can?

The changes in specific humidity might not be large enough to matter. Remember that specific humidity is different from relative humidity. The air in a combustion chamber is always going to rather controlled and known by the ECU as the ECU has a map or maf and knows the volume of the intake and cylinders.

>>16671377
wouldn't cooler air be more dense and therefore the engine could make more power? more air and so more fuel?

i always hear people say that the engines correct now-a-days, but my butt dyno says otherwise. (doesn't make me right)

>>16671454
>wouldn't cooler air be more dense and therefore the engine could make more power?
Sometimes. Sometimes not. The air is very cold on a tall mountain, but also thin. In the end it's about the mass of air going in, or honestly the amount of oxygen going in. I don't think, even on the most humid days, the ratio of water vapor to 02 in a given mass of air changes enough to make a difference

>>16671566
But sea level 85F versus 40F, more likely to be a difference?

I imagine a turbocharger or supercharger could make up some of the difference, depending on circumstances?

>>16671454
My turbo car feels more powerful in 0 degree weather than 70 degree

>>16672076
I wonder what temp they get dynod at

Humid air has more O2 than dry air of humidity, so would that cancel or magnify the error from O2 sensors in response to water?

In the absolutely hottest stickiest most humid jungle on earth water vapor is 4% of the air. At all other times you are looking at 1 to 3%.