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Old 01-14-2005, 12:05 PM   #26
gjhsu
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STi wing is PERFECTLY functional. Check it out



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Old 01-14-2005, 12:21 PM   #27
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I'll have to ask some of my German Impreza enthusiast friends if Sport Auto ever did this sort of test for the STi. Perhaps they can scan it and email it to me.
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Old 01-14-2005, 12:23 PM   #28
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Quote:
Originally Posted by RumblingREX
Splitting hairs here!

{cheap shot}
The wing may not be the WRC wing with all the proclaimed downforce yadda yadda, but you are an idiot if you think it does nothing at all!
{Fuel}
Bashing the wing for looks is one thing and totally personal opinion. Bashing the wing because you "think" it does nothing is just plain stupid. ... For daily commute and legal speeds I 100% agree, it does not add to the driving experience. The STi wing does vibrates at legal speeds, proving it is in the wind stream and providing some downforce.
{Match}
These wing threads or annoying the living crap out of the engineer in me. They are purely opinions stated to prove why the wing needs to go to justify a certain member dislike of the "look or visual limitations" of the wing. Just say what you want say "I Hate The Look Of The Wing!" Don't make engineering judgement to back up your opinions!
{Flame suit on and run!}
Hit the nail on the head here. Any wing will affect the car's handling. At what speed and how much is subject to the wing's design.

I doubt even the most intelligent fluids engineer could design a wing that had absolutely no effect at all speeds. You change the way the air flows and you affect the handling of the car. Positive or negative, it's there. Period.

I seriously doubt that the Engineers at Subaru sat around and thought, "hmm. can we make a wing that looks huge and then throw 100 grand or more at it in engineering to be sure it won't affect the car at all?" They missed the boat on a few things when they americanized the car, but that would just be stupid. And that's one thing Subaru engineers are not.
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Old 01-14-2005, 12:38 PM   #29
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Kinda like making a 6lb. crank pulley that isn't a harmonic balancer? Or a counterweight? Subaru engineers aren't dumb. You know they would try to improve performance (for the most part) wherever they can, yet there's still a 6 pound crank pulley. I say keep the stock pulley.

Oops, we were talking about wings, sorry.
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Old 01-14-2005, 12:41 PM   #30
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An added piece of pro-wing data to the other technical info.

You'll notice that the air flowing over the back of the greenhouse is actually going down? (look at the EVO wind tunnel picture back on page 1.)

Even though the wing looks level, it is actually angled down in the airflow that it acts in. So there is more angle of attack then is readily apparent to the eye.

The wing also has an airfoil section to it (though not THAT efficient) so that will also add some downforce to counteract the negative pressure on the back window and trunk lid.
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Old 01-14-2005, 12:53 PM   #31
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Yeah, the little blurb in the Evo excerpt says that having the wing set at a neutral position gives the car a fairly even lift characteristic front and rear. It goes on to say that at the steepest setting, 15.5 degreees, the rear lift goes from a reading of 349 newtons to only 84 newtons while the front, due to the revised angle of attack gains a bit from 307 to 366 newtons.
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Old 01-14-2005, 01:04 PM   #32
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I'm waiting for people to consistently pull faster lap times with the wing vs. without the wing...
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Old 01-14-2005, 01:15 PM   #33
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What is a wing supposed to do? Keep the wind from blowing the car off the road? Keep you from fishtailing? Let you corner 0.5% faster?

Does the wing just correct defects in the basic design of the vehicle?
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Old 01-14-2005, 01:27 PM   #34
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Quote:
Originally Posted by z&cobb
What is a wing supposed to do? Keep the wind from blowing the car off the road? Keep you from fishtailing? Let you corner 0.5% faster?

Does the wing just correct defects in the basic design of the vehicle?
If provides downforce.

The natural tendency of any vehicle without aero-aids is for the rear to lift at speed.

With the original Audi TT for instance this effect was so bad due to the basic shape of the car that at high speed it was compared to driving an airplane wing...ie as if the car wanted to leave the road all-together. Audi knew about this before releasing the car but felt the wing ruined the look. But after owners complained, and after there were some actual crashes on the Audobahn in Europe where drivers lost control of the car, they recalled it and added a small wing.

Funny the number of people who 'don't believe' in aerodynamics. This force lifts 100 tonne aircraft thousands of feet in the air. This force that will incinerate space shuttles on re-entry into atmosphere as if they were made of paper mache' and set alight with keroscene.


I wonder if TT drivers rip it off, because they are 'waiting' for proof of improved lap times.
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Old 01-14-2005, 01:36 PM   #35
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In that case a lead weight would survive your test of functionality.

Merely providing a downward force does not mean it provides value. Sorry.
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Old 01-14-2005, 01:40 PM   #36
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"that case a lead weight would survive your test of functionality."

Ohhh man. No it would not. A lead weight does not provide downforce. A lead weight does not counter lift. A lead weight provides inertia that would actually make instability due to lift 'worse' in transient conditions. You guys need to revisit those high school science books. You scare me sometimes.
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Old 01-14-2005, 01:50 PM   #37
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Yes a lead weight would counter lift (as would the school books you feel you mastered, or any other mass in the appropriate location) and I didn't state a lead weight specifically provides downforce. I stated "downward force", because it would do just that thanks to gravity.

IMHO your assumption that people "don't believe" in aero is incorrect; but rather many believe in aero when properly designed and applied, rather than "any aero is good aero even if it's drag with no proven value."
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Old 01-14-2005, 02:05 PM   #38
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Lightbulb Egg-head explanation.

The top side of the car has more area than the bottom side of the car. At speed this causes lift, like an airplane wing. This is because the same amount of air is moving a further distance and therefore must move faster. This higher velocity changes the air pressure seen at the surface, creating a difference in air pressure at the top of the car compared to the bottom of the car. This difference in above-and-below pressure causes lift. It's the same way an airplane wing works.

A wing on a car (Front or Rear) is designed to create some amount of downforce at speed. This should increase as speed increases, thus countering the natural lift encountered by the vehicle. The Audi TT is an excellent example of shape causing lift that can help you visualize the effect.

A well designed wing, or better yet, pair of wings, will provide the car with much needed stability at speed. And since the car in not symmetric from front to back, the car will display a change in handling as the rear or front of the car experiences more or less lift than the other end. Enter the wings. The rear wing and front wing, together with the aerodynamics of the car, can be tuned to provide the appropriate downforce (anti-lift) at either end, with the sole purpose of keeping the front and rear of the car balanced, ie, equal lift.
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Old 01-14-2005, 02:11 PM   #39
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"Yes a lead weight would counter lift" -

No it does not.

And this is my last post on this thread as the "waste of time arguing on the internet" factor is starting to kick in.

Lift is the component of force produced in the direction perpendicular to the relative airflow. Lift and downforce are a functions of airflow, and NOT weight. Weight has properties of inertia. Add a weight/mass (ballast) to the back of the car and when you turn it, there is a pendulem effect that adds to instability....meanwhile nothing has been done to decrease the aero-dynamic force of lift. Ballast is not the equivelant of downforce. They are fundamentally different properties in physics. And confusing them does not change the way they work.

Try to think of it this way. Without aero-aids the faster you drive the car...the more lift you get. With aero-aids the faster you drive the car...the more downforce you get.
Now, the above is itself an oversimplification, but should at least help you understand why performance cars have aero-aids and not 'lead weights' attached to the rear of the car.
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Old 01-14-2005, 02:12 PM   #40
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Quote:
Originally Posted by strangerq
If provides downforce.

The natural tendency of any vehicle without aero-aids is for the rear to lift at speed.

With the original Audi TT for instance this effect was so bad due to the basic shape of the car that at high speed it was compared to driving an airplane wing...ie as if the car wanted to leave the road all-together. Audi knew about this before releasing the car but felt the wing ruined the look. But after owners complained, and after there were some actual crashes on the Audobahn in Europe where drivers lost control of the car, they recalled it and added a small wing.
Actually they changed the suspension geometry and electronic stability control to prevent it crashing. At most the wing was there to augment the changes but the cynic in me wonders if they stuck it on to make prospective buyers think this had fixed the problem (esp when most magazines reckoned the handling of the car was degraded after the modifications).

There were several accidents in the UK that occured below 100mph which also caused the modifications to occur. I very much doubt a 5" wing changes the TTs handling below 100mph.

Quote:
Funny the number of people who 'don't believe' in aerodynamics. This force lifts 100 tonne aircraft thousands of feet in the air. This force that will incinerate space shuttles on re-entry into atmosphere as if they were made of paper mache' and set alight with keroscene.
Thanks for the science lesson.

I don't think anyone disagrees that the aerodynamics of the wing provides some downforce. The argument is more whether anyone can notice it.

I would severely doubt you can notice such small improvements in downforce at the rear of the car when downforce on a roadcar is an insignificant component in cornering performance compared to mechanical grip.
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Old 01-14-2005, 02:16 PM   #41
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What's also being confused in this thread (and I admit it's a fine point) is downforce with reduced lift. The function of the wing of the STi is to reduce the inherent lift that air flowing around and under the car at speed produces. It's not driving the rear axle towards the ground as much as stopping it from lifting up, and creating an environment where changes in the cars attitude would be exaggerated. A subtle but important aerodynamic difference.

I'm sure that day to day driving shows no benefit from this reduced lift. But get the car on a track at high speeds (I've had it as high as 135), and I'll tell you I'd rather have less lift than more.
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Old 01-14-2005, 02:23 PM   #42
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Quote:
Originally Posted by Neek
What's also being confused in this thread (and I admit it's a fine point) is downforce with reduced lift. The function of the wing of the STi is to reduce the inherent lift that air flowing around and under the car at speed produces. It's not driving the rear axle towards the ground as much as stopping it from lifting up, and creating an environment where changes in the cars attitude would be exaggerated. A subtle but important aerodynamic difference.

I'm sure that day to day driving shows no benefit from this reduced lift. But get the car on a track at high speeds (I've had it as high as 135), and I'll tell you I'd rather have less lift than more.
Well put. Basically, when the car approaches speeds that would normally make it squirrely, it prevents it from going squirrely. So hopefully, no you don't notice in in everyday driving. Just like you don't notice your airbags, which also add weight to the car and aren't used every day. They too serve a purpose, even if it isn't to create more traction or power.
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Old 01-14-2005, 02:58 PM   #43
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Quote:
Originally Posted by Neek
What's also being confused in this thread (and I admit it's a fine point) is downforce with reduced lift. The function of the wing of the STi is to reduce the inherent lift that air flowing around and under the car at speed produces. It's not driving the rear axle towards the ground as much as stopping it from lifting up, and creating an environment where changes in the cars attitude would be exaggerated. A subtle but important aerodynamic difference.
Outstanding synopsis!
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Old 01-14-2005, 03:42 PM   #44
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Good article about this:

http://www.imps4ever.info/tech/aero/tech_aero.htm

It's basically a continuum, progressing through decreased lift, and on to actual downforce production. In order for the STi wing to actually produce downforce and increase traction during a turn, would likely require a steeper attack angle on the foil as well as much higher speeds.

Supposedly, F1 cars create so much downforce that at speeds over 100mph, they could drive upside-down on the ceiling. THAT is aerodynamics at work.

Last edited by Neek; 01-14-2005 at 03:51 PM.
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Old 01-14-2005, 04:12 PM   #45
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Quote:
Originally Posted by strangerq
Lift is the component of force produced in the direction perpendicular to the relative airflow. Lift and downforce are a functions of airflow, and NOT weight. Weight has properties of inertia. Add a weight/mass (ballast) to the back of the car and when you turn it, there is a pendulem effect that adds to instability....meanwhile nothing has been done to decrease the aero-dynamic force of lift. Ballast is not the equivelant of downforce. They are fundamentally different properties in physics. And confusing them does not change the way they work.

Try to think of it this way. Without aero-aids the faster you drive the car...the more lift you get. With aero-aids the faster you drive the car...the more downforce you get.
Now, the above is itself an oversimplification, but should at least help you understand why performance cars have aero-aids and not 'lead weights' attached to the rear of the car.
Why do you assume people are thinking ballast is equivalent to aero? Who said that ballast doesn't have negative properties? Enough of the patronizing, no one is confusing mass with lift.

I'd love to see anyone back up the generalization that performance cars have "aero-aids" for the purposes of performance. (a better start would be flat bottoms with a rake and rear diffuser, which are quiet rare indeed)
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Old 01-14-2005, 04:19 PM   #46
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Quote:
Originally Posted by srf
Why do you assume people are thinking ballast is equivalent to aero? Who said that ballast doesn't have negative properties? Enough of the patronizing, no one is confusing mass with lift.

I'd love to see anyone back up the generalization that performance cars have "aero-aids" for the purposes of performance. (a better start would be flat bottoms with a rake and rear diffuser, which are quiet rare indeed)
I would go as far as to say most aerodynamic aids on most roadgoing vehicles have minimal advantage at all. Those that do, primarily have reduced lift, with safety and control in mind. I imagine it is a rare car that comes with actual downforce producing, performance enhancing aerodynamic aids. Then again, I'm not an engineer and haven't tested any of them, so I could just be talking out of my ass.
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Old 01-14-2005, 04:20 PM   #47
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.....

Last edited by afpdl; 01-14-2005 at 04:23 PM. Reason: whats the point
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Old 01-14-2005, 04:33 PM   #48
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interesting ... so is the WRX wagon somehow less stable because there is no wing? (I assume that little flat thing does basically nothing) What do cars like the S4 avant use?
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Old 01-14-2005, 04:44 PM   #49
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So far all discussion has been about downforce/reduced lift effect of the wing.

The wing also serves to improve straight-line stability through the vertical side-walls that act as rudders....it removal probably results in the "twitchiness" that de-winged STi owners feel at speed.

I would imagine that they are even more effective functionally than the downforce that the upper deck provides.

Either way, I find it hard to believe that Fuji would go through extra costs (to themselves and to their customers) just to slap on a "cool looking" wing....there are factors affected such as tarrifs due to the weight-calassification (remember the '04
didn't even come with floormats?).

Finally, given the cutthroat competition between the STi and EVO, why would Fuji attach a wing that would handicap their car?

This is my best crack at the wing-argument given the lack of factual data. I'd like to see some numbers though, maybe with the spec C wing thrown in for comparison.


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Old 01-14-2005, 04:52 PM   #50
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Please take another look at that diagram of the Evo I posted. Even at 125 mph, there is still lift. Even the Porsche has lift. However the accompanying text described how changing the rear foil's angle from neutral to 15.5 degrees reduced lift forces significantly. A lot of the newer cars like the Audi S4 and BMW M5 are using a lot of underbody aerodynamics to reduce lift. That is how they get away with, at the most having a tiny lip spoiler on the trunk. Believe me, these cars are designed to travel at serious speed and aero is not something to considered as cosmetic with these companies.

I spoke with my German contact and he is checking with the publishing house for Sport Auto. Perhaps in a few weeks time I'll have a similar diagram posted up with an STi. Cross your fingers!

Last edited by Arnie; 01-14-2005 at 05:00 PM.
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