soverystout

This topic doesn't warrrant any other post than:

Whether you think it looks good up or down(and both questions have been asked here) the simple fact remains that you should not inhibit the spoiler from doing the job it was designed to do or you pretty car could end up in a bunch of little pieces scattered all over the highway do to your vanity.

It is true that the beancounters at Porsche fought this spoile tootha and nail but the car would not function properly at speed without it.

AndyK

I vote for leaving the engineering to Porsche engineers! The spoiler breaks up the airflow at speed - why would you want to mess with that? Try going 70, and stick your hand out the window in spoiler position, and you'll see how much air even your hand deflects! Don't mess with science in favor of looks!

redridge

The previous 911... 993 and 964 spoilers were more for engine cooling. The impact of downforce was very minimal. 996 was the first 911 that actually produced downforce.... Ill post my source later, when I find it.

Macster

Never once in over 226K miles of driving my Boxster, and over 20K miles driving my Cayman or Turbo been pulled over cause spoiler's up.

Have not even been issued a ticket for having a radar detector and in fact used its presence to help convince a Texas LEO he made a mistake pulling me over for speeding (he did, only had eyes for the Porsche and not the car next to mind in the fast lane that passed me and triggered the excessive speed warning a the radar gun).

Lots of things to worry about while driving but that the spoiler being up is going to bring down the law on you for speeding is not one of them.

Sincerely,

Macster.

Macster

A "right on" to your "It is true...." comment.

Let the OP ask early Audi TT owners how they liked it when their cars were flying off the road cause the Audi beancounters won out and prevented a proper spoiler from being fitted to the car from the outset.

Sincerely,

Macster.

BruceP

Again, not to be pedantic, but none of those spoilers, old or new, were meant for creating downforce. That's what a wing is for. A spoiler is meant to keep the whole car from becoming a wing. They superficially look alike, but they're really two different things.

I'd hazard a guess that the 'downforce' created by our spoilers is close to zero, especially given that it's louvered. There's very little surface area to pressurize. The idea is simply to create controlled turbulence at the back of the car in order to counteract lift. Given that there is so little mass in the front of a 911, you can imagine that high speed lift at the rear could have pretty scary consequences.

IIRC, there are one or two pilots on this board. They could probably do a better job of differentiating the physics than I can.

BruceP

The perfect illustration. And they didn't fix it with a wing. They fixed it with a little strip of plastic meant not to create downforce, but to deliberately mess up airflow.

medtech

Technically the spoiler isn't even needed until somewhere around 90mph.
Porsche had to lower the threshold on the US cars or else they would never come up. (can't remember the source).

Edgy01

As a long time flier, let me enlighten you. The shape of the 911 is essentially that of a wing--the chord of a wing. By that shape, it naturally will want to move up because the air pressure on the top of the wing (car) is lower than the pressure beneath the wing (car). As such, the natural tendency is for it to want to fly. In the case of the 911, for it to raise up upon its suspension. The tails are there to essentially SPOIL that flow over the top rear of the car and keep it from raising up on its suspension. When you alter the shape of the wing chord you are altering the flight properties of that wing (car).

I started off my 911 days with a new 911S many years ago and it had no tail. When on the autobahns it truly wanted to fly. If I was alongside a black truck I could look out to the side and see that the rear end of the car was way up. It was literally trying to fly. Later, when I had a turbo-charged 911, it came with the Carrera RSR tail (first seen on the 1976 Turbo Carrera street cars). It made a pronounced difference when driving that car. I used to run it up to 5th gear redline routinely (162 mph) and I couldn't have done that safely without the tail. With my current car, the tail deploys at an honest 75 mph (77-78 indicated) and it absolutely keeps the rear rend down--enough to inspire confidence in the car's stability. I had it over 180 mph on the autobahns and felt quite secure. Several years ago in Porsche Panorama, they had an article about tails and air dams and such, striving to clarify the entire issue. The article discussed the downforces achieved from each type of tail. So the story goes, one day a long time ago (early 1970s) a Porsche mechanic took a car out for a test drive and had neglected to close the rear deck lid. He discovered how much more stable the car handled at speed. The 911RS wound up with a Duck tail soon, and the rest is history.

jmaisch

Thanks for all the input, but nobody has answered my question.
Is there a way for me to de-automate the rear spoiler while keeping
the option for manual deployment?

gota911

Yes it was. Robin answered it in post #3.