Question regarding a particular rear wing

[4.6MustangSteve]

Hello,

I've got a question regarding the effects of a particular rear wing on the 1999-2004 Ford Mustang body style. The wing in question is the Steeda "Race Wing."

http://www.steeda.com/store/-catalog/styling/wing.jpg

I'm wondering what sort of effects this wing will have on the car. Will it create downforce? Will it aid in stability? At what speeds would the vehicle have to be traveling to experience any noticable effects? The list of questions goes on and on.

People who use this wing on their Mustangs usually experience a drop of 1-3 mph in their trap speed at the end of a 1/4 mile. A friend of mine has this wing on his GT and his trap speeds dropped from 99-100mph to 97-98mph. I assume that the wing creates more drag than the factory spoiler.

If anything I suspect the wing smooths the flow of air as it travels over the rear deck. Anyone have other input?

 

[one_raven]

I am not sure if the new generation Mustangs suffer from the same problems of the last generation (I have driven a few of the new ones, but not really DRIVEN them yet), but I will tell you what I know from my experience with the 79 - 93 model years.

I know that Mustangs are known for (I have had a few, and driven many of them, and know it is true) for an "imbalance" in the front/rear weight split.

The engine (on the GT) was quite heavy, and the rear of the car was very light.

At take-off, it reduced grip on the road at high torque, so it was really easy to just pop the clutch and burn rubber in place if your starting RPM was too high.
(Ever try driving a Mustang GT in the snow? )

At high speeds (especially over 100mph) the back end would feel a little squirrely due to the light weight of the back, and the downforce on the front-end from the wind.

Some people actually kept sand bags, or welded heavy steel plates over the rear wheels to counter this.
Other people would drop the front end slightly more than the rear.
Neither of these worked quite well enough.

A "race wing" like that would increase the downforce on the rear without forcing the front down as well thereby increasing stability of the rear without adding extra weight (well, almost no weight) to the car. This downforce increases with speed, so the effect is stronger when you need it to be stronger. This extra downforce will mean that the car requires a little more power to accelerate as your speed increases, but the increase in stability is worth it.
(It does nothing for the starting line traction, but other measures can take care of that.)

I know nothing about the particular wing you posted, but a wing is not simply a wing.
The shape, height, size, curve, weight of the car, actual front/rear balance after mods... all have a huge affect on the performance, and you have to find the right balance.
If it is too large and swooped up, then the downward force on the rear will end up in too much of a loss of power at too low of a speed by adding more downforce than necessary, for example.

There are more than a few magazines that are solely dedicated to fast Mustangs.
Check those out for honest reviews of that exact make and model wing on a similar year/model/weight Mustang (and if you are lucky, similar mods done).
You can also check out Mustang owner internet forums and ask who has which wings and their before/after numbers.

If you know a good and honest modern Mustang performance specialist (there are quite a few of them) you could also talk to them about specific manufacturers and their specific models.

 

[ken]

Hi

I don't know of this particular wing either but here is some math.

L = 1/2 * p V^2 * S * Cl

Where :

L = Lift
p = Density of air ( 1.225 Kg/m^3 at sea level)
V = velocity of air
S = Wing plan surface area
Cl = coefficient of lift.

A high lift wing for a car spoiler could probably produce
a Cl of 1 - 1.5

So let's say the wing is 1.5 metres long and .15 metres wide,
.225m^2 and the car is doing 50 m/s (180 km/h)

L = .5 * 1.225 * 50^2 * .225 * 1.5

L = 5176 Newtons
That's an estimated increase in effective weight of 52.7Kg

Now aerodynamic forces are proportional to the square of velocity
so at half the speed, you have 1/4 of the lift and 1/4 of the drag.
So you are not going to pay much drag penalty at lower speeds, only at heigh speeds when you really need the spoiler the most.
You could expect drag to be less than 1/30 of lift.