04-18-2013, 05:26 PM | #1 |
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Driving with back windows down...
Whenever I drive with back windows down (Either passenger or driver), it makes this loud vibrating sound (like pulsating *sorry hard to explain). it feels like its wind hitting some non aerodynamic surface. It makes driving with back windows down unbearable.
This is stopping me from getting tint because I know the dealer would blame on it. Is this common? I remember that some cars have block on the back windows so that it doesn't go all the way down. Is this same issue? |
04-18-2013, 05:33 PM | #2 |
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Every car with 4 doors that I've driven has this phenomenon. I don't know the physics behind it, but the simple solution is to just crack your front window an inch when you decide to open the rear windows.
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04-18-2013, 05:57 PM | #4 |
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04-18-2013, 06:19 PM | #5 |
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Yes its pretty bad, the F30 is the worst I have seen this effect. Normally I drive with one rear window down for the dog.
On my Lexus (RX350) there is no such effect - the only thing you notice is that the radio gets a bit louder. What I have noticed is that if you open both back windows this helps. Opening the sunroof also reduces it a bit, or a front window (drivers) seems to stop it.
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04-18-2013, 06:27 PM | #6 | |
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/sarcasm Probably just different window geometry...the design folks likely overrode something a pimple faced engineer suggested after wind tunnel testing.
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04-18-2013, 08:09 PM | #7 |
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With back windows open the wind builds up a pressure toward the back of the car but there is no outlet, the pressure builds untill it is higher than the incoming air pressure causing it to spill back out against the incoming flow-this happens repeatedly and causes the buffeting-you may also notice your ears feeling it.
Solution is to have one window open, the other side cracked so the high pressure on the open side can escape on the low side. It's even worse with the sunroof open and no windows open, again cracking a back window lets out the pressure. |
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04-18-2013, 08:15 PM | #8 |
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When i drive, in a nice awesome day, i would like to pull all my windows down also the pano roof and enjoy teh Sun and Chicks Winking
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04-18-2013, 09:20 PM | #9 | |
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04-18-2013, 10:16 PM | #10 |
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Not an expert, but it probably has to do with either high/low pressure or air speed associated with a fast moving vehicle. As others have said, crack a front window, or what I like to do, vent the sunroof.
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04-18-2013, 11:38 PM | #11 |
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vent or open the sunroof... and crack one of the rear windows...
I always do that... that prevents the pulsating wind noise...
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04-19-2013, 07:55 AM | #14 |
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It's turbulance/resonance depending speed, quiet normal. Answer already posted by "Number", like opening one of the front windows an inch for handling air pressure. Also opening sunroof helps. The same (normal) phenomenom happens on fully opening (twice sliding button) the sunroof with all windows closed. (that's why 2 stage designed)
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04-20-2013, 05:29 PM | #15 | |
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My E91 and F11 with panoramic roof always need the rear windows cracked open if I drive with a fully open roof at anything over 30mph. Had many cars over the years with a sunroof and all the same to some degree. HighlandPete |
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04-22-2013, 10:19 AM | #17 |
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04-22-2013, 04:00 PM | #18 | |
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Get your car tinted. It's great. Don't let this worry you.
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04-22-2013, 05:11 PM | #19 | |
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Perhaps there are other cars that are worse - I just have not been in them. The F30 is pretty severe - the dog insists on the LHS rear window all the way down, and even at 30mph is is bad. Not that it worries me - I just open something else. Usually everything else, and turn on the heated seats.
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