I was wondering something today as I was driving to work.

It was a nice 75 degrees outside and I didn't want to turn on the climate control.

So I tilted the moon roof and everything was great.

Now I read that opening windows at highway speeds decrease fuel efficiency.

Now it must be the same with the moonroof. With it tilted, I don't think I get a decrease in fuel efficiency.

But what if the moonroof was completely open? Would that have the same effect as having the windows open?

 

Wow man, you think too much

 

Who gives a damn - enjoy the car while taking full advantage of the weather while its here. I live in New Hampshire, the days are numbered that we can enjoy a great car with all the windows open on a spectacular day.

 

Mythbusters did a test on this on a racetrack.

It showed virtually no difference. And this was in an Expedition. Don't worry about it.

 

Geez, I was just wondering...

 

In tilt mode, I suspect the moonroof adds little to no drag. Fully open, though, there's probably some added drag, but not so much in the grand scheme of things that your mileage is going to tank.

 

I suspect that the wind deflector helps when the moonroof is open.

It doesn't help so much in wind noise reduction but it redirects the air up and over the opening thus reducing drag.

I think.....

 

you are funny. By opening the moonroof won't really decrease that much fuel efficiency. Now, if you drive it hard and rough, it will.

 

Exactly. I drive with the windows down and sunroof open all of the time except for the extreme summer and winter...doesn't matter if I'm going 80 down the interstate, I just turn the stereo up some more. Why? Because I enjoy it, and that's all that's important.

Besides, fuel economy won't decrease that much...and even if it did go down a mile or two per gallon, who cares? You only live once...you should try to spend as much time doing what you enjoy as you can.

 

hahahaha... is this for real?

 

yeah, while driving the car, you should not worry about stupid little things like that but instead listen to the roar of the TL engine...............among other things

 

It increases down force by an incredable weight by acting as a spoiler. Try some narly turns with it closed, and then it in tilt mode, you will notice an Extreme amount of control gained when in tilt mode, you could probably pull over 1.5gs on the skid pad!

 

I heard that if you drive really fast and you stick your left arm out the window and pretend to fly like Superman that it will decrease your gas mileage. Especially if you raise your arm up 45 degrees just to feel the wind resistance and then back down and then back up and then back down and then back up....

 

You guys are funny. Sarcastic. But funny. I like the tilt = spoiler theory. Really...just enjoy the car!

 

Based on the drag of the car of the windows down vs. the auto climate control (CC), having the windows down is more fuel efficient than the CC up to about 35 MPH. Above 35 MPH, the climate control is more fuel efficient.

I agree with other people in that you should just do what works for you!

 

well, first off, a 1mph headwind would probably effect your fuel econ more than a tilted moonroof...

In addition, there is something called laminar flow and boundry layers. It sort if is why you can have your window down and barely stick your hand out the window, and you won't really feel any drag. Similiar to the way water droplets on your hood close to your windshield don't really "move" like the droplets more toward the front of the hood when going high speeds. also, like the way a bug can be on your windshield near the bottom and can stay there even while going 50mph. It is possible that the roof doesn't stick up all that much into the high velocity flow. As an airplane wing moves through air, the velocity at the skin, most noteably the further back you go on the airplane, the velocity approaches near zero. You could stick a square blob a couple inches high toward the back, but on the flat bottom part of a 767 and it would cause virtually no drag... it gets complicated, I'm not an aero engineer (I'm an ee), but I do work at boeing (military side)

 

okay, maybe a little higher than 1mph since drag has to do with V²

I should have said airplane body, but true for wings too.



While I'm typing out the word QUOTE, might as well have some fun....
Umm.... yeah.....

 

You never NEED gas, you could just walk, but I love the roar of a Vtec in the morning.

 

As your dad drives you to school?



I had to say it.

 

Yep, the disruption of airflow over a surface causes drag. It's like riding a bike over a nice smooth bike path and then all of a sudden you hit a small pothole or bump.