Aero Limitations
#1
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At what speed does the problem of rear lift become an issue with a non spoiler 3.2 with IROC front?
Then how 'severe' as in big, does the spoiler need to be to address the problem?
Then how 'severe' as in big, does the spoiler need to be to address the problem?
#2
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How do you mean 'an issue?' The car will feel more planted with front and rear spoilers, but it's perfectly safe and acceptable without either, even at autobahn speeds.
Worn bushings and out-of-spec suspension/alignment settings are more often the cause of high speed darty-ness or drift.
Worn bushings and out-of-spec suspension/alignment settings are more often the cause of high speed darty-ness or drift.
#3
I haddah Google dat
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Paul Frere's book "Porsche 911 Story" covers the lift numbers of the various types of spoilers very well. Porsche apparently used wheel scales and a wind tunnel. I don't recall seeing any info on the IROC front though. There is a casual mention of cross winds stalling the wing shape of the front hood. I experienced this wide-open on a sweeping turn on Highway 46 on the way to the central coast (same road James Dean died on), and it was very scary.
#4
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As Jack said, there really is no issue, but rather a difference in feel or manners. My Targa, with stock front valance and no spoiler got a bit light and squirelly at about 90+. With front factory spoiler and my old Carrera tail, or my current duck, it feels much more planted at the same speed. Gets a bit light at 140 or so.
#6
Poseur
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When I lived in Europe with a non-tail 911S in the good old days I used to drive fairly fast on the autobahns. If you're doing straight line stuff the downforce is nice, but not nearly as critical as when in turns (banks). But I do recall a trek down to Switzerland for lunch one Sunday when I went over a curving bridge joint at about 120 mph and sure WISHED I had a tail. Those cars get floaty above 90-100 mph.
#7
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How do you mean 'an issue?' The car will feel more planted with front and rear spoilers, but it's perfectly safe and acceptable without either, even at autobahn speeds.
Worn bushings and out-of-spec suspension/alignment settings are more often the cause of high speed darty-ness or drift.
Worn bushings and out-of-spec suspension/alignment settings are more often the cause of high speed darty-ness or drift.
chris
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#9
RL Community Team
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My 1985 with a factory chin spoiler and no tail has been stable for me up to 130mph.
#10
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Last edited by irobertson; 07-01-2010 at 03:29 PM. Reason: Fixed Link
#11
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#12
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They're similar. Both help with engine cooling, too.
#14
uninformed gas bag
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(contemplating on whether gas bag is one or two words)
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http://www.youtube.com/user/mussberg.../4/py6lO8jiubE