Rear spoilers and wings, chin spoilers, splitters, and diffusers are all modifications that not only give your Mustang a more aggressive look, but that also can offer performance boosts as long as you pick the right parts for your build. Whether you’re looking to reduce drag, increase downforce, or just give your Mustang a customized look, there are plenty of options for everyone.
Types of Rear Spoilers
Rear spoilers are one of the most common sights on Mustangs. In addition to being easy to install, spoilers add to the overall appearance of a vehicle, giving it a sportier look. There are a lot of different styles of rear spoilers, and while the right one can improve performance, selecting the wrong type or installing it incorrectly can actually have a negative effect.
On an un-modified car, airflow comes down over the roof towards the rear of the car and down over the back edge of the vehicle. As it does, it creates two things you definitely don’t want: Drag and lift. The lift pulls your wheels off the ground (a serious detriment in a rear-wheel-drive vehicle) and the drag slows you down. The end result is a slower and less stable vehicle. Spoilers disrupt that airflow and prevent it from pulling the car downward, reducing drag.
There are a lot of different spoiler styles, and to some extent the rear spoiler that’s right for your build is going to come down both to personal preference and also what will fit on your Mustang, which is why it’s important to pay attention to what generation a spoiler is designed for.
Ducktail Rear Spoiler
Ducktail spoilers are aptly named. Once you see it like a duck’s tail, it’s hard to unsee that image. Essentially, a ducktail spoiler seems to almost come up out of the trunk and form a slightly tapered wedge shape across the trunk. Sometimes the ducktail spoiler doesn’t even span across the whole trunk, emphasizing the ducktail appearance. The ducktail was originally a ‘70s invention, designed for the Porsche, but since then it’s seen expanded use.
Pedestal Rear Spoiler
Pedestal types are actually the most common type of spoiler, though defining how they look is significantly harder than some of the more precisely named types. This modification is an easy bolt-on that fastens to the trunk of the vehicle. It has the look of a bar that goes across the trunk, hugging closely, but allowing for a slight gap of air. The goal of this style of spoiler is simply to create a small amount of downforce that can improve handling in a rear-wheel-drive car. There is a lot of variety in pedestal spoilers, so they’re one of the styles that is more frequently added to improve the overall aesthetics of a vehicle.
Not to be confused with a front or chin spoiler, lip spoilers create a slender “lip” on the edge of a trunk. One of the subtlest rear aerodynamic accessories, a lot of vehicles come with lip spoilers. These spoilers, despite their small size, are actually surprisingly effective. By disrupting the air just slightly and softening the angle air exits the vehicle at they are able to reduce drag and lift. At legal speeds, a lip spoilers effect will be minimal, but they do look very attractive.
Obviously, roof spoilers are going to be a fastback-only option. These spoilers go at the very top of the back windshield and disrupt the airflow before it even has the opportunity to approach the trunk of the vehicle. Though primarily installed on hatchbacks, roof spoilers are growing in popularity amongst sedans as well as part of a total aerodynamic solution.
From Cervini’s famous stalker spoiler to the deep cup shape of the Fox Body Mustang Spoiler first made by Saleen and now replicated by many, a lot of the most interesting spoilers are manufactured by famous performance shops and are named accordingly. Roush Performance spoilers have been especially popular for the S550 generation of Mustang, but there are countless options to select from for the Mustang enthusiast who wants a unique look.
Although wings and spoilers both reduce lift, they function very differently. While spoilers reshape airstreams, wings deliberately catch them, pushing the air up and the rear of the vehicle down. Rear wings increase drag significantly, so they really don’t make much sense off the track unless you like the aesthetics of them. By pushing the rear end of the vehicle down, wings ensure that the vehicles maintain stability even while making incredibly fast turns.
Whale Tail Wings
While rear spoilers have many different styles that are common, rear wings tend to all be fairly unique with one notable exception. The Whale Tail. First designed by Porsche, who also designed the ducktail, the whale tail was the ducktail’s more imposing cousin. Like the ducktail, the whale tail seems to sweep up from the trunk, but while the ducktail creates a slide edge, the whale tail is significantly larger. These are sometimes also called “tea trays” due to their slightly raised edges.
Whale tails are primarily used for style now. Though there is some evidence to suggest that they help to reduce oversteer when cornering, that’s been a difficult claim to substantiate. Regardless, they do look unique.
Gurney flaps are essentially a small tab that projects from the edge of a wing. Named for the race car driver who invented it (Dan Gurney) this is one of the simplest styles of spoiler. Regardless of their simplicity, gurney flaps can negatively affect your car's performance if installed poorly.
Essentially, a Gurney Flap is a piece of metal fixed at a right angle that increases the downforce on a rear wing or spoiler, which improves traction. Or at least it does when it’s pointed up. Pointing the flap downwards negatively impacts performance.
Neither a wing nor a spoiler will help if you’re just driving around town in a straight line, but they both definitely have performance functionality in other scenarios.
Mustang Chin Spoilers
Chin spoilers are sometimes called front spoilers or air dams. These parts are also sometimes added purely for aesthetic value, but, like spoilers, they do serve a purpose. Underneath your car is a topographical map of valleys and mountains that catches air, creating drag and lift. A front air dam prevents that. By decreasing drag and increasing downforce, the chin spoiler provides an easy performance boost in handling. As an added benefit, the increased airflow can help to keep your engine a little cooler.
Splitters are attached to the front of the car and look like a flat scoop. Because the downforce on splitters can be intense, they’re often supported by small metal support rods. The splitter actually works as a wedge, sending the low-speed, high-pressure air over the car and the high-speed, low-pressure air underneath the car. The overall effect? Reduced lift and subsequently increased front tire traction. Resulting in increased grip in high speed turning situations.
One of the most famous splitters for Mustangs is the iconic front splitter printed with “Shelby” but there are plenty of great splitters available for every Mustang, whether you’re driving a Shelby or an Ecoboost.
Another way to generate a low-pressure zone to increase downforce is to use a rear diffuser. True to their name, diffusers help to direct the air as it makes its journey underneath your car so that it doesn't create too much drag. As you can imagine, much like splitters, these modifications don't do much for cars that sit high above the road. On a sporty car though they can also contribute to the overall 'look' of performance and speed.
These are some of the easiest performance modifications you can make on your Mustang, and in addition to enhancing the performance, you’ll also be adding to your Mustang’s appearance in a way that’s sure to turn heads.
Aftermarket parts’ material composition has an effect on how they perform as well. While fiberglass and ABS remain popular choices due to cost and ease of painting any parts that don’t come pre-painted, carbon fiber is growing in popularity as the cost decreases. Additionally, it’s becoming increasingly easy to find quality composites that combine the best features of multiple types of materials.
Because many aftermarket parts don’t come pre-painted, you’ll want to make sure you find your Mustang’s paint code and order a paint that matches. Few things will look quite as off as a Velocity Blue Mustang with a Lightning Blue spoiler. That said, some enthusiasts have abandoned matching all together and instead purchase their aftermarket parts in a uniform color like black to provide a contrast to the color of their Mustang. Ultimately, it’s up to you, but thinking through these choices in advance makes it easier to achieve the aftermarket look of your dreams.