I had a moon roof put in my '03 XRS, and I love my car! (aside from the clutch right now, but I am getting info from here about that, thank you very much!)
If the roof is open all the way, or the back windows are all the way down, the roof will flex repeatedly, making kind of a helicopter noise & feel - I'm told it's called "roof flex". It's really disconcerting.
I'm told that people who have super woofers also experience this problem.
Any suggestions on ways to reinforce so that this won't happen?
If I had known about this, I might not have had it put in - but I got my '03 in '02, and no one knew...otherwise I love the car so much I could sell them!
That's an interesting issue, I've never heard of that...but let's see, how to fix that....super glue and duct tape, my usual solutions to issues, don't seem like they'd be very helpful...
Damn, I got nothing. I was trying to think of a way to reinforce the roof, but can't think of any means that's not overly destructive to the interior of the car. A roof rack might help, but I strongly doubt it. If you could run a metal support across it, that might help too, or just weigh the roof down somehow so doesn't push up as easily during flexing. Damn. I'll keep thinking about it, see if I can come up with anything better, although I probably can't. That's a tough problem, good luck with it. Maybe you can talk to the guys who put the moon roof in and they can do something?
Since this is something we've never seen reported before, I'd have the roof checked. Maybe the stock bracing wasn't properly installed or has a broken weld. It is not a normal condition.
Wait. Hang on a sec. This HAS been mentioned before. Just not brought up as "roof flex". The "helicopter noise" will occur in non-moonroof Matrices. Go ahead and try it those of you who haven't experienced it. You'll have to drive around 55mph or faster for it to happen. Once you get to that speed, open the rear windows all the way down (leave the front windows up).
I think calling it roof flex is over-exaggerating the phenomenon. All it really is physics, wind and the design of our cars creating that sound.
I hate it. It kills my ears. My daughter sometimes forgets to raise her window up when we get on the highway.
The air pressure thing pappens on alot of different cars. But one thing you can do to help stop the actual flexing is by deadening the roof with products like Dynamat.
Oooooooooooooooooooooooooh that noise! Yeah, that has nothing to do with anything flexing.
That happens on damn near every car ever made, ever. It's a matter of the aerodynamics of the car creating pressure zones that get screwed with when you open the window. It's annoying, but there's an easy solution....close the window when you go fast. Either that or beat your car with a 2x4 until the aerodynamics of your car are utterly ruined
Wait. Hang on a sec. This HAS been mentioned before. Just not brought up as "roof flex". The "helicopter noise" will occur in non-moonroof Matrices. Go ahead and try it those of you who haven't experienced it. You'll have to drive around 55mph or faster for it to happen. Once you get to that speed, open the rear windows all the way down (leave the front windows up).
I think calling it roof flex is over-exaggerating the phenomenon. All it really is physics, wind and the design of our cars creating that sound.
I hate it. It kills my ears. My daughter sometimes forgets to raise her window up when we get on the highway.
Yes! That's it! It happens at as low as 25 mph sometimes if the roof is open, though. The place where I bought the car says there's nothing to do...I will investigate the other option someone mentioned. I am really starting not to like the place where I bought the car...am changing dealerships as of this clutch install at 33000 miles.
The air pressure thing pappens on alot of different cars. But one thing you can do to help stop the actual flexing is by deadening the roof with products like Dynamat.
Toyota makes a plexiglass wind deflector for the moonroof/sunroof that will help that problem a lot. It's a common problem with both rear windows open only OR with sunroofs open. The deflector should help a lot.
i believe wind deflectors are available for the side windows as well.
i'd look into that and then consider finding other ways to get decent airflow without getting the annoying sound. cars these days aren't really designed to drive with the windows down. they put so much attention into the aerodynamics and opening a window totally throws that balance off.
This is a copy of another post of mine at a Corolla site.....
Every car I've ever been in made an annoying helicopter thrumming sound like a wind tunnel when you drive at high speed with only the rear windows open. From my buick to my civic to my XRS, they all do it.
This is why we have "air conditioners". They make the air cold and dry so we can be comfortable while driving at high speeds.
Most people bring up the fact that the AC wastes power and ruins gas milage. Here's the thing....There are some things you have to deal with. You can't drink a whole bottle of tequila without puking, and you can't drive down the freeway with your windows open without that annoying sound. You also can't have the AC on without leeching power.
So what is one to do? Someone posted a link to an article where they stated that under 45mph to keep your windows open, but after 45mph you will burn more gas with the windows open due to the ruined aerodynamics than you would with the AC on. So under 45mph, windows open, over that turn on the AC.
Or you could do what I do......windows up, sunroof tilted, with the vent on. All the air that the vent spits out blows up past my face (cooling me off) on its way out the sunroof. I get insane milage this way.
Our cars are very aerodynamic from the factory, with the windows up. I don't think it's possible to make a car that is aerodynamic with the windows down unless you had a hatchback with an open window in the back.
The Matrix A/C appears to be very efficient. Twice this summer I drove a particular 300 mile round trip at 50-60 MPH at 90-94 degrees F with the windows closed and A/C on low (which kept the car comfortable) and got 43 MPG both times!!! I'm a mileage freak, so I was careful not to exceed 60 MPH even in stretches of road when I could have gotten away with it (it was all state highways with mostly 55 MPH speed limits). Clearly this is close to ideal driving conditions for fuel economy, but to get 43 MPG with the A/C on, it must not be sucking TOO much extra power from the engine!
I get that problem if I open just one window all the way and leave the others closed. Try opening another window part way (just a couple inches) and see if that helps. Usually, I open my drivers all the way and leave the passenger side open just a bit.
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