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View Poll Results: What type of tail
Turbo
19
16.81%
Carrera
33
29.20%
Duck
33
29.20%
none
28
24.78%
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Tails!

Old 08-25-2011, 02:20 PM
  #46  
whalebird
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So at 130mph, your looking at removing 200#s from the rear of the car. How much does an engine weigh? We know what a 911 sans engine looks like. Perceptible lift certainly.
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Old 08-25-2011, 03:24 PM
  #47  
SARGEPUG
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Originally Posted by Ed Hughes View Post
OK, read that, and look at the pics they show. Then go to the R&T or C&D article on the Porsche ducktail, and some other published data that shows Porsche was able to reduce lift on the cars via the tails in the 70's and 80's.

I'm going off memory, but the car in the mag test took 250 or 300lbs of lift (measured via an articulated bicycle wheel affixed to the back of the car) and took it down to 80 or so.

Now, with a GT3RSR, anmd certainly Formula and prototype race cars, there are aero aids that provide true downforce. But the rudimentary achievement of a basic tail, at the speeds our cars run, is that it is a "spoiler" that negates lift. The shape or a 911 and an airfoil are quite similar.
It actually says spoiler on the wiki site as well. I totally understand you on the lift, but how can you say that the tail doesn't create more downforce? It even states it on the wikipedia page. The basic principle of the tail catching the air, is a force in which is pushing down on it / keeps the rear better seated. I think the tail's generated downforce, is what keeps the rear from lifting.

Last edited by SARGEPUG; 08-25-2011 at 07:58 PM.
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Old 08-25-2011, 04:48 PM
  #48  
g-50cab
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Originally Posted by whalebird View Post
So at 130mph, your looking at removing 200#s from the rear of the car. How much does an engine weigh? We know what a 911 sans engine looks like. Perceptible lift certainly.
from ~low 400's to upper #400's - 3.2's and early 3.6's weigh the most...
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Old 08-26-2011, 02:03 AM
  #49  
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I'm a firm believer in form following function; too many Pontiac Grand Ams on the road now with spoilers.

I added my spoiler back in the mid 80's when I noticed my SC felt very light at speeds above 110 or so. Yes I drove fast back then. On one trip from Houston to New Orleans, I remember straddling the white line in the middle of the interstate and noticing that the car tended to drift slightly, and steering input did not have as immediate an effect like it did after I installed the front lip and rear spoiler. The car was much more stable at high speeds with the spoiler. Steering input was immediately noticeable.

I went with the turbo tail at the time. I just wish I would have kept my original engine lid and bought a separate one. I don't regularly drive at those speeds anymore and could get by now with no tail.
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Old 08-26-2011, 10:49 AM
  #50  
theiceman
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Originally Posted by SARGEPUG View Post
It actually says spoiler on the wiki site as well. I totally understand you on the lift, but how can you say that the tail doesn't create more downforce? It even states it on the wikipedia page. The basic principle of the tail catching the air, is a force in which is pushing down on it / keeps the rear better seated. I think the tail's generated downforce, is what keeps the rear from lifting.
#semantics .. i think that ship has sailed ..

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Old 08-26-2011, 01:36 PM
  #51  
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in addition to the issue of effect of lift on straight line stability, I am thinking it also affects the initial braking at speed such as the end of a longer straight. if you are getting lift and then start to brake hard, it diminishes the ability of the rear brakes to be effective. and can contribute to limiting the amount of initial braking without getting some rear lockup. on the tracks I run, I am in the 120 range.

need to get a lip and duck before next track season.....
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Old 08-26-2011, 02:19 PM
  #52  
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It all depends on the flairs... the bigger your car's flares, the bigger a spoiler you can get away with.

Narrow-bodied 911's look best with no spoilers.
Carrera-flared cars look fine with either the ducktail or Carrera spoiler.
Turbo-flared cars look great with the tea-tray spoiler.

If your spoiler overwhelms your flares, ie: a turbo tea-tray on a Carrera-flared car, you end up looking ridiculous.

Just one man's opinion, YMMV.
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Old 08-26-2011, 10:04 PM
  #53  
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Originally Posted by exc911ence View Post
It all depends on the flairs... the bigger your car's flares, the bigger a spoiler you can get away with.

Narrow-bodied 911's look best with no spoilers.
Carrera-flared cars look fine with either the ducktail or Carrera spoiler.
Turbo-flared cars look great with the tea-tray spoiler.

If your spoiler overwhelms your flares, ie: a turbo tea-tray on a Carrera-flared car, you end up looking ridiculous.

Just one man's opinion, YMMV.
I agree with this 100 %
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Old 08-27-2011, 05:48 PM
  #54  
autobonrun
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Originally Posted by SARGEPUG View Post
It actually says spoiler on the wiki site as well. I totally understand you on the lift, but how can you say that the tail doesn't create more downforce? It even states it on the wikipedia page. The basic principle of the tail catching the air, is a force in which is pushing down on it / keeps the rear better seated. I think the tail's generated downforce, is what keeps the rear from lifting.
I've got an excellent article on this if I can locate it. However, he's right that the primary purpose of a spoiler is to "spoil" the airflow over the top of the car eliminating lift; not to create downforce. It fundtions the same as flaps on an airplane wing.

An airfoil or "wing" on the other hand actually creates downforce. Basically, the tail design on cars like the RS3 incorporates an inverted airplane wing; negative lift.

Although most conversation is on the rear wing, the front spoiler is also important to redirect air around the car rather than underneath; just another tool to reduce lift.

Last comment with respect to looks, Porsche solved the dilemna with the retractable spoiler. However, I can't recall once thinking about my car's looks when I was at 120 mph; but I do remember thinking about how it wasn't responding well to steering inputs.
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Old 08-27-2011, 06:11 PM
  #55  
Ed Hughes
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....and as I was tooling around early this morning at "liftoff speed", I marvelled at how sure-footed she was for a 27 year old car with 140k on the odo.
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Old 08-29-2011, 01:35 AM
  #56  
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my favorite wing.




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Old 08-29-2011, 04:43 PM
  #57  
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Originally Posted by Euronavy View Post
my favorite wing.
Hey euronavy, you should add a front spoiler as well. See prior posts in this thread for the reason why.
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Old 08-30-2011, 01:41 AM
  #58  
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Yep, i agree, i am searching for a good one right now
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Old 08-30-2011, 05:33 PM
  #59  
autobonrun
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Originally Posted by Euronavy View Post
Yep, i agree, i am searching for a good one right now
Absolutely beautiful Porsche you have there.
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Old 08-30-2011, 09:12 PM
  #60  
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Euro,

You really need to get some "Period correct" Fuchs! Those wheels misrepresent your great ride.
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