Roof scoops. You may have noticed it in a racing game, or perhaps you’ve seen it in a photo of your favorite hypercar. While not a very common feature in vehicles, roof scoops, which are roof-mounted air intakes, have been around for quite some time in the automotive industry.
In this article, we’ll discuss the functionality and implications of roof scoops.
The Purpose of Roof Scoops – Short Answer
A roof scoop is intended to provide air to the engine of mid/rear-engine vehicles. While in rally racing vehicles, roof scoops are used to provide clean air to the interior cabin, preventing dust from entering the space of the driver.
The functionality of a roof scoop is very important for rally racing and mid/rear-engine cars. If you are considering adding a roof scoop to your vehicle or are simply curious, there are some things you need to know first.
How does a roof scoop work?
Roof scoops for mid/rear-engine cars:
Providing cool air to an engine is essential for a vehicle to operate. Without this, the engine would overheat, which could potentially cause the metal to melt into the engine blocks, effectively destroying the engine.
Front engine vehicles receive air through the grille. The grille, a mesh-like opening at the front of the automobile, allows cool air to enter the engine compartment under the hood. This allows air to move through the engine manifold and the engine’s radiator, which keeps the engine from overheating.
Performance cars that have engines mounted in the back need a way to provide air to the engine and radiator. This cannot be done using a front grille because the engine is not located directly under the hood. Instead, mid/rear-engine vehicles feed air into the engine and radiator using side-mounted intakes, or NACA ducts.
NACA ducts are inverted intake vents designed to pull air in without creating extra drag. These side scoops and NACA ducts are normally located behind the door. They can be slightly in front or above the rear wheels.
If there isn’t already enough air entering the engine compartment through the side vents or NACA ducts, some mid/rear-engine cars will opt to include roof scoops to provide more air to the engine.
Let us take the McLaren 620R as an example,
The base model McLaren 620 has side vents mounted behind the side windows. However, on the 620R model, buyers are given the option to have a top-mounted roof scoop replace the window-level side-mounted intakes. The top-mounted intake (roof scoop) can be seen in the image above.
Air enters the roof scoop intake, which then splits route between the rear window frame, entering the 2 sides of the engine manifolds.
Advantages of roof scoops
There are many advantages in choosing a roof scoop to either complement or replace other vents. The 4 main advantages are as follows:
- Engine sound: The roof scoops are right above the ears of both the driver and passenger. With the intake being directly connected to the engine itself, the engine sound can be heard through the roof scoops. This makes for an exciting driving experience.
- Clean air: Roof scoops provide clean air because the intake is positioned slightly above the vehicle. This way, the amount of debris going into the intake is dramatically lower than side or front grille intakes.
- Direct air: Side vents may not be receiving an ideal amount of air during a manuvering situation. The air flowing going into side vents is from air being routed along the aerodynamic curves in a car, which leaves a lot of air on the table. Airflow is also limited to one side when the vehicle is turning a corner. Roof scoops do not have this problem, as air passes into them directly without being blocked by the sides of the car or bounced away along the curvatures.
- Increases engine pressure: In mid/rear-engine vehicles without turbochargers, roof scoops can increase the engine pressure at high speeds which can potentially increase the power output. An increase in engine pressure effectively boosts performance in the same way a turbocharger would.
Roof scoops in rally cars:
Rally cars often drive in harsh off-road terrains such as dust, mud, and snow. Any vehicle racing through such conditions would face difficulty maintaining a suitable cabin pressure, or temperature. These conditions create a pressure vacuum within the cockpit of the vehicle, forcing outside debris and hot air (from the engine) into the cabin, causing the visibility within the cockpit to dramatically drop. To solve this issue, rally cars use roof scoops.
The roof scoops in rally racing vehicles are used to maintain a pressure equilibrium between the inside and outside of the cabin. The roof scoops allow clean air to enter through the roof of the car, which stabilizes the pressure, thus preventing dust from pouring into the cabin.
Adding a roof scoop to a car
If you are interested in building a rally racing vehicle or just like the look of having a roof scoop, then you should know that you can add a roof scoop to your car.
Roof scoops can be added to most vehicles, so long as it is without a sunroof. You can either opt to purchase a third-party roof scoop or mold one yourself. The installation process of a roof scoop is similar to that of installing a hood scoop.
The following video illustrates the method by which most aftermarket roof scoops are installed:
When choosing the install a roof scoop into your vehicle, it is important to carefully consider the design and material of the roof scoop.
What roof scoops are made of
Design of roof scoops:
With any roof scoop, there will be aerodynamic implications that must be considered. Roof scoops effectively raise the aerodynamic height of the vehicle, which increases the drag and reduces the downforce. Due to this, roof scoops are designed to be as thin as possible.
To maximize the amount of air received, roof scoops are made as wide as possible, this is especially the case with a mid/rear-engine performance car. To make up for the increased drag and loss in downforce, performance cars may add a spoiler or raise the height of an existing spoiler to increase the overall downforce at higher speeds.
A typical roof scoop will be made from either aluminum, stainless steel, carbon fiber, plastic, or a combination of some/all of the said materials.
1. Stainless steel:
Stainless steel has many applications in automotive manufacturing and is perhaps the most versatile metal in the industry. Stainless steel provides many benefits. It is ductile, tough, and relatively lightweight when compared to other metals. The deciding factors of using a stainless steel roof vent are cost-effectiveness and corrosion resistance.
Much like steel, aluminum is known to be a very versatile metal. It’s corrosion-resistant, ductile, odorless, and flexible. The biggest advantage aluminum has is it’s very lightweight compared to steel while providing many of the same benefits.
While it may not be as strong as the other materials mentioned on this list, what plastic lacks in terms of strength, it easily makes up for in cheap production costs. Plastic does not corrode and is very lightweight. Weight reduction is very important in a performance vehicle, even if it is just a roof scoop. A few kilograms in reduction can make a difference in a race where the tiniest of milliseconds count.
4. Carbon fiber:
Carbon fiber is a staple material in the high-end performance car market. Carbon fiber is far light lighter than steel and is the strongest material on the list. It is also the most expensive to produce. The practicality of carbon fiber heavily depends on the production cost of the vehicle.
While a rally car may not necessarily need carbon-fiber roof scoops, it’s almost always the best option for a high-performance supercar. A mid/rear-engine sports car with a roof scoop will be moving at very high speeds, producing very strong aerodynamic forces. Materials like plastic will not do ideally in this case as the wind forces could break the plastic material.
When the price of production is not taken into account, carbon fiber is the best material to use for a roof scoop, as seen in most performance cars today.
7 production cars with roof scoops
McLaren F1 (1992)
The McLaren F1 was perhaps the greatest supercar ever built and was one of the very first, if not the first production car to wear a top-mounted air intake. Many car manufacturers soon followed suit by adding roof scoops to their hypercars.
The car was first unveiled in 1992 and was equipt a 627hp 6.1L V12 engine which could do 0-60 mph in a whopping 3.2 seconds. The F1 reached a top speed of 240 mph and was the fastest car in the world until the Bugatti Veyron took the title 13 years later in 2005.
Lamborghini Diablo SV/SV-R/GTR (1995)
Following suit after the McLaren F1’s top-mounted air intake, Lamborghini implemented a roof scoop into the design of their Diablo in 1995, the successor to the long-standing Countach.
The car could get to 202 mph and did 0-60 in just 3.4 seconds with its 5.7-liter V12 engine producing up to 575 horsepower and 457 pound-feet of torque. The Diablo was the first Lamborghini to have a roof scoop intake.
Porsche 911 GT1 (1996)
The Porsche 911 GT1, preceding the current 911 GT2 and GT3, was Porsche’s hypercar of the 90s. The car debuted in 1996 and was the official successor to the iconic Porsche 959. It was Porsche’s first and only car to have a roof-mounted air intake.
The GT2 boasted a 3.2L twin-turbo flat-6 engine producing up to 536 horsepower and 443 pound-feet of torque, and it could do 0-62 mph in just 3.9 seconds. The roof-mounted intake fed air directly into the engine manifold.
Bugatti Veyron (2005)
The Bugatti Veyron took the world by storm during its debut. The French car’s goal was simple, to unseat the long-standing top speed king, the McLaren F1, and it did just that.
The Veyron’s produced a ridiculous 1184 horsepower with its massive 8.0-liter W16 quad-turbo engine and had a record-breaking top speed of 268 mph. The engine produced so much heat, it need 10 radiators to cool the engine along with 2 massive roof scoops.
Koegnisegg Agera (2010)
Although the Agera was released in 2010, Koenigsegg first started implementing roof scoops to the Agera in 2014, with the Koenigsegg One:1.
The Agera was powered by a 5.0-liter V8 engine. It produced 947-1341 horsepower depending on the model (R/S/One:1/RS/Final).
McLaren P1 (2014)
The P1 was McLaren’s official hypercar successor to the F1. It carried over many of its design features, including the iconic roof scoop.
It had a 3.8-liter twin-turbo V8 producing 727 horsepower and an electric motor producing an additional 177 horsepower, combining to produce 903 horsepower and 723 pound-feet of torque.
The McLaren P1 was a track-focused vehicle rather than a top-speed-focused car. At 217 mph, had a slower top speed than its predecessor, the F1.
McLaren Senna (2018)
Though not a direct successor to the P1 or F1, the Senna is part of McLaren’s ultimate series, alongside the F1 and P1. McLaren chose to carry over the iconic top-mounted intakes to the Senna as well.
McLaren’s roof scoops enhance the supercar experience. The engine’s intake location, placed directly above the driver’s head, made hearing the engine’s symphony all the more exhilarating for drivers.
It produces 789 horsepower and 590 pound-feet of torque with its 4.0-liter twin-turbo V8.
Functional roof scoops are an essential part of a vehicle when needed. As discussed, many considerations go into the design and incorporation of roof scoops.
Rally racing vehicles need to use roof scoops to maintain a stable pressure within the cabin. Without it, the racers would be unable to see due to the dust pouring into the vehicle’s cabin.
The functionality of roof scoops in mid/rear-engine cars is very similar to that of a hood scoop/vent. In the same way that hood scoops feed air into the manifold of front engines, roof scoops do so for mid/rear engines.
Mid/rear-engine performance vehicles, most notably McLaren’s production/track cars, use roof scoops as a functional air intake to supply air into the engine manifold.