ABA testing with windows up and down?
 

We all know you get worse gas mileage with the windows down on the highway. Even throttle stop testing and coast down shows windows down creating more drag. But has anyone on the forum actually done some ABA testing with mpg numbers? What about windows just cracked an inch?

Also side note- snow and ice build up on the side of the car or roof line and splatter around wheel arches Really hurts your mpg big time!

windows & mpg
 

Where it's humid, and it can feel like 100-F, when it's 80-F, without AC, you almost wish there was no glass at all!
At 65-mph, by 'tank' mileage I've seen a 2-3 mpg loss with the side windows down, and slider rear window open.
Running the AC at the same speed meant around the same 2-3 mpg loss. So it was a 'wash.'
With modern heat pump systems, I suspect that its more efficient to keep all the windows up, and just run the AC. And on full-recirc where it's super humid.

Oh yeah it’s definitely better to run the ac in modern cars. I was just wondering how much impact on drag coefficient windows down has

how much?
 

It can be reverse-engineered using the mathematics.:)

I have an underbody hole about the size of a window lol

But to run the A/C you would need to uncover the radiator, so factor in the increaed drag from removing the grille block.

Ac is working fine with my grill block right now?