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991 Window Buffeting Solution

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Old 11-03-2012, 09:40 AM
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BGB Motorsports
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Default 991 Window Buffeting Solution

I am hearing stories of cars with sunroofs that go boom inside the cabin; either way, I am shocked that more people haven't experienced turbulent buffeting with both windows down in non-sunroof cars on the highway. I'm working on a solution hopefully in the $100-$200 range in carbon fiber or painted that will bolt on and solve this. Our car is a non-sunroof car for obvious reasons. I'm shocked at how severe the issue is at typical highway speeds. Now, if I could convince someone in Germany that the 997/987/991 hanging clothes hook on seat back or window is just plain unacceptable, we might get somewhere. And i thought Duallys were bad! We have no intended solution for that though! Sorry!

Can we see a show if hands if you have experienced the cabin turbulence? PM for more info.

Thanks.
Old 11-03-2012, 05:40 PM
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shizzle
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I experience the buffeting mostly at the track where we need to have both windows down, sunroof closed and speeds over 100mph. I'd be interested in a solution.
Old 11-03-2012, 10:36 PM
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fbroen
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For cars that are not track only, a snap-on solution might be better than bolt on. Wing mirror to window trim something or other.
Old 11-04-2012, 01:03 AM
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Sorry. I meant snap on. This is more for the street and not the track. Thanks!
Old 11-04-2012, 06:07 AM
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peewee72
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so far no buffeting issues on mine with sunroof.

does it only come on where u have the windows opened and not the sunroof?

i pretty much have my sunroof opened all the time..
Old 11-05-2012, 12:36 PM
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CDinSing
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Mine is dual purpose street/track car with no sunroof and yes buffeting is an issue at the track. On the street I just close the windows. So a snap on solution for track days would be welcome. I don't need carbon fiber for track days. I was thinking about something simple built from an engineered plastic; small, light and cheap to make. My pre track day breakfast should weigh more than this solution. CF would be expensive and overkill.
Old 11-05-2012, 04:05 PM
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ScorpionT
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Originally Posted by CDinSing
Mine is dual purpose street/track car with no sunroof and yes buffeting is an issue at the track. On the street I just close the windows. So a snap on solution for track days would be welcome. I don't need carbon fiber for track days. I was thinking about something simple built from an engineered plastic; small, light and cheap to make. My pre track day breakfast should weigh more than this solution. CF would be expensive and overkill.
The problem with plastics is a mold charge is always incurred, so for low volume parts CF and FRP are generally less expensive.
Old 11-05-2012, 10:58 PM
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Originally Posted by CDinSing
Mine is dual purpose street/track car with no sunroof and yes buffeting is an issue at the track. On the street I just close the windows. So a snap on solution for track days would be welcome. I don't need carbon fiber for track days. I was thinking about something simple built from an engineered plastic; small, light and cheap to make. My pre track day breakfast should weigh more than this solution. CF would be expensive and overkill.
For the track, some painters' tape and a block of styrofoam (or anything) taped to the mirror arm would suffice. Not beautiful. Sure to reduce straight line speed above 150 mph by 1 or 2.

Everyone should be wearing some sort of earplug. The cabin of even the quietest road car at 120 mph with the windows down is deafening. Literally.

I guess the real solution is to put an end to this nonsense of defeating the safety of a modern car by compelling drivers to have the windows open.
Old 11-09-2012, 03:28 AM
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Edgy01
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Side windows down and sunroof closed I found that buffeting was really pretty bad in the 997 coupes. Doubt that has changed in the 991. Sadly, in 1978 when Porsche did away with the opening of the two rear side windows it eliminated a nice way to get air flow without buffeting.
Old 11-10-2012, 11:38 AM
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Originally Posted by Edgy01
Side windows down and sunroof closed I found that buffeting was really pretty bad in the 997 coupes. Doubt that has changed in the 991. Sadly, in 1978 when Porsche did away with the opening of the two rear side windows it eliminated a nice way to get air flow without buffeting.

I wonder if adding canards to the front bumper would disturb the air enough. Maybe combined with the spoilers on the back of the front wheel arches?

Surely somewhere along their millions of miles of testing, someone had to report "insufferably noisy buffeting at speed with windows down" but then, what was done?
Old 03-09-2014, 11:21 PM
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fbroen
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Originally Posted by Carrera GT
Surely somewhere along their millions of miles of testing, someone had to report "insufferably noisy buffeting at speed with windows down" but then, what was done?
It would appear that Chevrolet did something for the Volt:

"Chevy comes up with Volt mirror modification to stop wind thumping"

http://green.autoblog.com/2013/12/22...p-wind-thumpi/

.

Last edited by fbroen; 03-10-2014 at 10:36 AM. Reason: link corrected
Old 03-10-2014, 08:47 AM
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Originally Posted by Edgy01
Side windows down and sunroof closed I found that buffeting was really pretty bad in the 997 coupes. Doubt that has changed in the 991. Sadly, in 1978 when Porsche did away with the opening of the two rear side windows it eliminated a nice way to get air flow without buffeting.
I've owned both and 991 is worse. When I first drove my 991, I couldn't believe they actually tested the car in the wind tunnel and on the road. Both windows down, it's very bad unless you crack the sunroof (unacceptable at many tracks). Porsche has already found a solution in the $600 sport design mirror option that is included, free, on the GT3 and Turbo S. It seems pretty clear that Porsche recognized the buffeting issue, but instead of simply changing all 991's to the new style mirror, they decided to charge for correcting their own design flaw.

I hope that John and the BGB guys can come up with something.
Old 03-10-2014, 09:05 AM
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THPorsche
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I don't think the new style mirror can be folded.
Old 03-10-2014, 09:16 AM
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Originally Posted by THPorsche
I don't think the new style mirror can be folded.
Right, but they don't need to fold. The split in the mount cuts down the buffeting quite a bit.
Old 03-10-2014, 10:25 AM
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ohniner
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Those of us with 991 cabs have the same issue. Cannot have the window down all the way or else there is buffeting.


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