nick49

The problematic hydraulically movable wing is right where I want it...wrapped in a towel hanging on the wall in my garage. The ducktail lip on the rear deck is still there and if needed I believe will provide necessary down force.

I regularly drive in excess of the century mark, 105 yesterday between tight turns down a steep canyon road near home.

I'm of the impression Porsche created the movable upper wing as a sales tool, not much more. I may be very wrong, but I don't think so.

I cant' help to wonder why some of those who try to achieve speeds in excess of 200 mph would remove their upper wing if it would adversely affect high speed stability. This has been discussed in another forum.

Another thing to ponder. Excessive down force on the rear will make less or lift on the front. This has been a problem with previous Porsche's I've owned. At around 105-125 mph they started feeling really floaty and like on the verge of becoming uncontrollable.

kato1453

When I bought my car, the wing went but still had failing light on dash. Luckily, found Factory aero rear wing at LA Dismantler, changed out and never looked back.

neanicu

Sounds to me you're trying to convince yourself that you made the right choice.
Knowing Porsche engineering I highly doubt(matter a fact,I'm 100% convinced) that the wing is for looks only.

SSST

I'm not sure I would want to test your theory at 150. For normal street driving, I doubt you will notice a difference. On a track, pushing the limit through a high speed sweeper, you will probably see the difference.

Besides, there is the cool factor to consider with the trick spoiler.

If mine goes when it's out of warranty, I will probably get the kit that fixes it in the up position. That's the safest bet.

kezcapt

I'm a believer in keeping the car the way it was designed. I think it makes the car value better and I admire porsche's style and engineering. I hope that my remark about downforce is not taken to suggest that I think it should be removed, just that in the time it takes to fix it you won't be the subject of a crash investigation. There is on other function not widely discussed which is the "spoiler" function. One rennlister made mention of the height relative to a GT2. The presence of the spoiler in a low pressure zone is no accident as it also serves to "spoil" the airflow off the rear and trailer the car. This reduces drag and moves the trailing low pressure vortice to a point behind the car. This works in conjunction with smooth under body panels to enhance aerodynamics.

Kevinmacd

Nick you need to keep in mind the lower lip spoiler in the front. Tis decreases igher presssure under the car. I don't think the spoiler is a marketing tool. As I sad in my previous post Porsche distinctly says that operating the turbo over 75mph without the rear spoiler deployed can cause one to loose control. It's in the owners manual. So from my perspective, why would they put that discaimer in the manual, if in fact it had no handling contribution, and I am sure they put that in the book to keep from getting sued! Another thing to keep in mind why use a hydraulic system if there was insignificant downforce. They could just as well used a electric servo motor, which would be cheaper if no significant downforce was observed. Think there are too many skeptics!

Macster

A case can be made if one is seeking a max speed number removing the wing.


The wing (or spoiler when up) represents some drag and as speed goes up so does the drag.

I've read reports of drivers not only removing the wing but taping over body panel gaps, removing wipers, and folding back the rear view mirrors.

All reasonable actions if one is on a track or closed course getting ready to enjoy a v-max run.

The section of the road or track/course at least where the highest speeds will be obtained is probably straight, or smooth and level with little or no crests dips or camber changes get the car unsettled.

Sincerely,

Macster.

Dock

Of course our spoiler system contributes less down force at lower speeds; the wing doesn't even deploy until 75 mph.

But to the point, you didn't mention "low speeds" anywhere I could see. This is what you posted..."As the spoiler produces very low amounts of down force to begin with...". That's your statement I replied to.


The overall affect of the rear spoiler system is not just from the lift (down force) produced by the airfoil of the extended wing. The movable wing is part of an overall system. When the wing is extended, the fixed duct tail is exposed fully to the relative wind, and this accelerates the airflow over the lower surface of the wing (an increase in "V" in the equation). With the rear wing extended, the package also effectively reduces axle lift by better controlling the airflow at the very back of the car.

Kevin

Dock can speak from experience.. He uses the "Lift Coefficient" almost every day.

kezcapt

The overall affect of the rear spoiler system is not just from the lift (down force) produced by the airfoil of the extended wing. The movable wing is part of an overall system. When the wing is extended, the fixed duct tail is exposed fully to the relative wind, and this accelerates the airflow over the lower surface of the wing (an increase in "V" in the equation). With the rear wing extended, the package also effectively reduces axle lift by better controlling the airflow at the very back of the car.[/QUOTE]

I don't know why I bother but... Raising the wing has nothing to do with the velocity constant and the only way you can change the relative wind would be to change tha angle of incidence, not possible on a fixed wing. The variable changed would be the Coefficient of lift. It is defined as:
The relationship of the lift force, fluid density,true airspeed, dynamic pressure, and planform area. Raising the wing would increase Bernoullian effects which are directly dependent on CL.
I have no Idea why you insist on pursuing the matter but you will undoubtedly win the subsequent conversation as it will be with yourself.

Dock

The wing is not operating in a stand alone environment. The duct tail directly below the wing affects regional airflow.

MK19

I see a lot of this.......here's what worked for me. KEY POINT is that oil leaking from one ram may will go away in a well balanced and operatiing system and stay away......it did for me.

Forget the external cleaning........the real crud is down in the rams where you can get at it.

NOTE: a small film of hydr. oil coats the rams (small pin rams inside the big chrome slides you can see outside) and some very small evaporation takes place with use.........over 7-10 years, this evaporation eventually will cause an out of sync condition when you've never had a single drop of oil leakage. Once out of sync, the system tends to push oil through the sael on one or the other of the ramss due to high loading on one side. The crud that tends to stick the chrome sides doesn't help a bit......but may not be the real problem in most cases.

Here's the sequence to fix:
1) raise the wing and then renmove it........lots of other posts on wing removal.
2) lower the rams, and remove their upper snap rings to get them apart. This can be done in or out of the car, feel free to open the hoses........we'll re-bleed next. CAREFUL: There are springs inside (used to help retract the rams).......no dangerous load when the rams are retracted.
3) Clean the Chromed external sliding surfaces of the rams and the I.D.'s of their mating sleeves. This is where youi'll find the crud you can get at otherwise. I wouldn't lube beyond maybe a light rub with a silicone spray...certainly nothing that will collect dirt like a greese or oil. Put the rams all back together. Don't install the wing.
4) Flush and re-bleed:
a) Uncover the hydr. pump under the deck lid so you can apply an external power source. Note a battery charger will do it and note that swapping the input polarity reverses the direction of the pump.
NOTE: the pump is really two syringes driven in parallel by a motor driven screw..........this is how it synchroniozes the two rams........out of snyc rams means one side has less fluid in it than the other.....simply, the fliud colums are different in length.
b) Submerge both of the open hose ends (the ram end banjos) in a few ounces of fresh hydraulic oil (as used for power steering and for the small hydraulic brake reservoir up front). A clear container is good so you can see the fluid exchange and when the air is blead out.
c) Cycle the motor back and forth until all the air is out. CAUTION: don't over heat the electric pump motor.
NOTE: the total oil volume in the pump is very small..........maybe an ounce or so........so don't expect any big flow or spray here, and the fact that the flow is very small doesn't mean the pump is shot either.
d) With the hose ends STILL submerged in the oil.........retract the pump .......i.e. draw in a full fluid charge. KEEP the hose ends submerged.
d) Reconnect the hoses to the rams; A spare pair of hands hepls but yopu can do it alone too. Just have your self set up so that you loose the least oil from the dripping hose end as possible as you pull the hose end out of the oil container and get the banjo bolt and washeras screwed in. Do one hose after the other keeping the second one submerged until you are ready to connect it up. Some loss is inevitable and no big deal.
e) cycle the rams up/down 6-8 times.........their operation will become consistent.......although they will probably be out of sync. due to different oil loss during the two hose connections.
f) Sync the two rams: Realize that the big springs are pusing the Chrome rams down......and the oil in the hose/pump is pushing them up aginst the spring load. So following the manual more or less;
f1) raise the rams to a mid point.
f2) on the ram that sticks up the highest, crack the banjo bolt on its end allowing the ram spring to force to bleed bit of oil out as the ram lowers matching the height of the other........go back and forth a bit until they are within about 2 mm or 1/16 inch of each other........perfection is nice, but not required.
NOTE: If you let too much oil out.........refill the pump per e)above and start over.
g) Cycle the rams up and down to be sure they remain pretty closely synced........and re-install the wing.
NOTE: you'll end up with oil all in and over the rams and it may appear to leak.........drive and clean with the black covers on the bottom over the banjo bolts off for a week or two to be sure you either really do have a leaky ram........or just long term 'run off'.

Again; these leaks go away when well blead and synced..........at least they did for me. I did my daily driver over a year ago and its fine and dead dry today.

Best of luck. MK19

turbosjedi

Update in the damn spoiler from hell….the car was in the garage for over a week. They replaced the motor, the switches, the controller unit and something else. Failed to deploy the VERY first time I hit 75 on the freeway. This is starting to become really frigging annoying.

Mark Dreyer

On the topic of wings, my opinion from personal experience a couple weekends ago is that the wing definitely isn't for looks alone. I have done hundreds of laps at Sebring in my Boxster S race car pictured in my avatar, and have never spun the car (other than on a caution lap on green tires which I forgot were very slick). A couple weekends ago, I got the bright idea to remove the wing to see if I could improve lap times by getting faster on the straights. I noticed a definite loss of stability, but not only in the high speed sweepers like Bishop's Bend, but at about 60 mph through the carousel, I lost the car and spun. I did hit the tire wall, but fortunately, it was a low speed kiss by time I got there and no major damage to the car. Anyhow, that wing is back on my car, and my point is from my perspective, that even at a relatively low speed, the wing adds stability.

wross996tt

text book physicists seldom understand the real world (and they seldom take into account measurement uncertainty in the theoretical models).