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Registered
Join Date: Aug 2005
Location: san francisco
Posts: 1,547
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Does a ducktail w/ no front spoiler matter?
On a 1974 911 street car, will the addition of a ducktail without the addition of a front spoiler adversely effect handling? If so, will it really be able to be noticed?
Thanks- Craig Backer |
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Moderator
Join Date: Dec 2001
Posts: 9,569
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Yes, it is wrong. If you are going fast enough for the duck to matter, you are going fast enough for the lack of balance witih the front to matter. Don't do it.
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'66 911 #304065 Irischgruen ‘96 993 Carrera 2 Polarsilber '81 R65 Ex-'71 911 PCA C-Stock Club Racer #806 (Sold 5/15/13) Ex-'88 Carrera (Sold 3/29/02) Ex-'91 Carrera 2 Cabriolet (Sold 8/20/04) Ex-'89 944 Turbo S (Sold 8/21/20) |
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Join Date: Aug 2005
Location: san francisco
Posts: 1,547
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What kind of speeds are we talking here?
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Join Date: Jul 2001
Location: Portland Oregon
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Quote:
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Steve Weiner Rennsport Systems Portland Oregon (503) 244-0990 porsche@rennsportsystems.com www.rennsportsystems.com |
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PRO Motorsports
Join Date: Nov 2001
Location: Burbank, CA
Posts: 4,580
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On a '74 and later car, you're fine.
The depth of the front valence on a '74 and later was designed to match the lip of the '72-'73 S spoiler bumper. So with a duck and a stock crash bumper front valence it will be balanced. With anything bigger like a Carrera tail or IROC, you'd need the front rubber spoiler.
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'69 911E coupe' RSR clone-in-progress (retired 911-Spec racer) '72 911T Targa MFI 2.4E spec(Formerly "Scruffy") 2004 GT3 |
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will be insteresting data points this weekend as I switch from the duck to iroc for CA Speedway (but I have a stock front spoiler). Wondering if I'll need more front with the big AIR f/g iroc.
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drag racing the short bus
Join Date: May 2002
Location: Location, Location...
Posts: 21,983
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If it is of any importance, I believe '74 Carreras came from Porsche equipped with the duck tail, but no front lip spoiler.
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The Terror of Tiny Town |
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With my limited knowledge I would have thought that a duck tail without front spoiler would be ok- because the duck tail gives less reduced lift and but it does reduce drag- than the Carrera tail/turbo tail.
I have found my 71 targa with no spoiler/tails to be very light above 80-90mph. Being that the car is not 'really' designed for these speeds on a regular basis I try to keep under them!. As for tracking a car it appears all to often that aesthetics go out the window with huge tails and tail extensions, front splitters and ground effects! just my 2 cents
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AKA "86ragtop" 1986 911 Carrera SOLD 11/2001 1984 Carrera 3.2 IROC RSR look |
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durn for'ner
Join Date: Feb 2005
Location: South of Sweden
Posts: 17,090
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My lip and wing less Carrera feels significantly more sensitive to wind at speeds above 60-70 mph as compared to my friends with both. But it´s prettier..
![]() In this case I prefer design before function.
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Markus Resident Fluffer Carrera '85 |
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PRO Motorsports
Join Date: Nov 2001
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Todd, you're not likely to need more front with the Big IROC. You're still not to the point of any NET downforce in the rear yet.
Of course, the rest of the package may affect this, like where you have the roll couple set with torsions and swaybar settings. And the biggie, which is rake. Rake affects aero, and also affects the rollcouple since it changes the relation between roll center height versus center of gravity differently between the front and rear when you alter the rake. In other words, if you do feel you have aero-induced handling issues, you can raise or lower the front of the car to alter the roll-couple, as well as the center of pressure fore-aft. FWIW, I'm currenty running an IROC wing with an early S spoiler with a very small splitter, and it works very well. Might push a little too much at faster tracks, but I'll cross that bridge when I come to it.
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'69 911E coupe' RSR clone-in-progress (retired 911-Spec racer) '72 911T Targa MFI 2.4E spec(Formerly "Scruffy") 2004 GT3 |
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At CA Speedway today I was flat in 5th by the end of the front straight (not at redline though), topping out at around 130mph. Car felt quite stable. I like the iroc. Banking is a good thing too, although it does scrub speed. Now if I could just not look at the other guy that spun, causing me to dispy doodle, losing 20 seconds on the lap and 5 places...
practice, practice, practice... |
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Administrator
Join Date: Feb 2000
Location: Los Angeles
Posts: 13,333
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Weirdly, Fontana really isn't an aero track.
Willow is.
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Jack Olsen 1972 911 My new video about my garage. • A video from German TV about my 911 |
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