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How important is the 991 rear spoiler for stability/downforce?

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Old 02-21-2018, 08:20 PM
  #61  
chuckbdc
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Thanks for that posting- very interesting. But I don't understand your comment (Downforce doesn't exist?? ).
Old 02-21-2018, 08:25 PM
  #62  
STG
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Originally Posted by chuckbdc
Thanks for that posting- very interesting. But I don't understand your comment (Downforce doesn't exist?? ).

Meant for the ONE member here who says the rear spoiler/wings/etc are just feel good features and do nothing for performance.

Yes, downforce does exist and is REAL.
Old 02-21-2018, 08:30 PM
  #63  
subshooter
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Originally Posted by Nyati
I can't see my spoiler at all on my 991.2 non sunroof C4S from the driver's seat. I see the rear hips - that's it.
You can see it. You gotta sit up high (stretch) and look far out to your left in the mirror and you will see the edge of the spoiler up.
Old 02-21-2018, 10:45 PM
  #64  
bkrantz
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Originally Posted by asia
Here is a chart with drag/lift data for 991.1 compared to 997.2. Lift values depend on chassis type.

I have not found 991.2 data. The 991.2 rear spoiler can be extended to provide additional charge-air cooling via ram pressure.


Are the listed values for spoiler stored or deployed?
Old 02-21-2018, 10:51 PM
  #65  
bkrantz
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And speaking of drag (which nobody has metioned so far, except for Asia), it is relatively easy to generate positive or negative lift while ignoring drag. For a street car, seldom above 80 mph, canceling lift, especially at the rear, is nice--unless it adds significant drag.
Old 02-21-2018, 10:59 PM
  #66  
Dewinator
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Old 02-21-2018, 11:26 PM
  #67  
Valvefloat991
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Originally Posted by asia
Here is a chart with drag/lift data for 991.1 compared to 997.2. Lift values depend on chassis type.

I have not found 991.2 data. The 991.2 rear spoiler can be extended to provide additional charge-air cooling via ram pressure.

Interesting. I'd be curious to see the lift values for the standard, full ride height chassis. It would be also nice to see if the drag values changed as the chassis was lowered.
Old 02-23-2018, 01:20 AM
  #68  
auchenberg
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Wooha! What an interesting and great thread!

Conclusion: I'll stick with my SportsDesign Ducktail for now. It's a great snow catcher! ��������

​​​​​​

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Old 11-13-2018, 05:31 AM
  #69  
sirtom
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Anyone have any downforce data for the sport design ducktail?
Old 11-13-2018, 10:33 AM
  #70  
StormRune
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Originally Posted by sirtom
Anyone have any downforce data for the sport design ducktail?

The chart by Churchill at post 55 in this thread shows a prior model ducktail and is probably close.



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