Eventuri Intake Audi B9 RS5 / RS4 Carbon with Secondary Duct

Intake AUDI B9 RS4 RS5

Performance gains: 11-16 HP, 12-17 Nm (at the wheels)

The Audi B9 RS4/RS5 Eventuri intake has been developed to provide less restricted airflow to the turbocharger while maintaining low inlet temperatures. The RS5/RS4 engine bay quickly heats up, so having an open cone system would simply result in better airflow but at higher inlet temperatures. Therefore, we completely redesigned the intake tract from the turbo inlet pipe to the radiator core support, creating a highly efficient, sealed system. The restrictive factory Airbox and flexible plastic intake pipe were replaced with a Venturi filter housing and smooth channel system. Additionally, by removing the convoluted factory intake pipe and replacing it with a one-piece Venturi housing and fixed pipe, the airflow is much smoother as it enters the turbocharger inlet pipe. The performance gains and aesthetics achieved are leading in this industry.

Eventuri Difference

The B9 RS4/RS5 Eventuri system utilizes their patented carbon fiber housings with specially designed Gen-2 filters, providing an aerodynamically efficient airflow path from the filter to the intake pipes. This is not just another cone filter with a heat shield but a unique design that induces a Venturi effect. More information on the housing design and its operation can be found HERE.

Performance Test

Below is an independent dyno chart comparing the Eventuri system to the factory Airbox in the B9 RS5 model. The car had no other modifications. As shown, power and torque are increased across a wide range of engine speeds. This translates to increased response when partially and fully opening the throttle, and the car accelerates more eagerly towards the redline. Tests were conducted on the same day, one after the other, and temperatures were monitored to ensure consistency. Hoods were closed during all trials.

The gains stem from a combination of reasons:

1. The sealed system maintains low inlet air temperatures—especially with the front air inlet forcing airflow into the system.

2. The Venturi housing provides a smooth transition from the filter to the intake pipe without convoluted rubber sections. This helps the turbocharger work more efficiently by maintaining laminar flow in the intake tract.

3. The entire system is made from pre-preg carbon fiber, which effectively insulates from heat.

Eventuri B9 RS4/RS5 Kit

It consists of several components designed to fulfill specific tasks and crafted with the utmost care. Here are the details of each component and its design concept:

Each intake system comprises:

• Carbon fiber Venturi housing with integrated pipe
• High-flow Generation 2 filter
• Carbon fiber intake channel
• Carbon fiber front air inlet
• Carbon fiber additional air inlet
• High-quality silicone connectors and hose clamps meeting OEM specifications
• Laser-cut stainless steel mounting brackets
• CNC-machined mounting plugs

Installation of the carbon fiber inlet housing

The filter housing consists of our individually designed Generation 2 filter, a carbon fiber capsule, and an integrated pipe. The carbon fiber capsule surrounds the reverse-mounted filter and smoothly shapes the airflow downward to the turbocharger pipe, matching its diameter to the turbocharger pipe. This is a key feature of the intake design, where we eliminated the need for convoluted rubber hose between the inlet and the engine. The filter housing and integrated pipe extend all the way to the factory turbocharger pipe, and when mounted to the engine, the entire filter housing moves with the engine. As the engine and filter housing accelerate, it is able to maintain a seal to the channel due to the use of a rubber extrusion that expands and is fixed to the front of the channel (see below).


This gradual reduction in cross-sectional area induces the Venturi effect, where the airflow accelerates while maintaining laminar conditions. This can be likened to a large speed cone—below is a diagram comparing the patented Eventuri design to a standard intake system. Individually crafted filters assist the airflow passing through the housings and allow for a consistent velocity profile as the airflow exits the housings.

Carbon fiber intake channel

The channel guides atmospheric air from the inlet to the filter housing. It also creates a sealed volume of atmospheric air in front of the filter, ready to be drawn by the filter. The channel is designed to make the best use of the available volume in the engine bay. To provide good insulation from heat from the engine bay, the channel features flexible rubber seals around the openings, which press against the filter housing and factory intake channel, creating the desired seal while allowing the housing to move with the engine. To further improve airflow, we added an additional opening at the rear of the channel in the cold zone of the engine bay. This geometrically complex element is a crucial part of our design for B9 RS4/RS5 models.

Additional carbon fiber channel

For a complete carbon fiber set, we also created an additional carbon fiber channel. This component connects the main carbon fiber channel to the area of the front bumper air inlet. It eliminates holes in the factory part and integrates with the rest of the system, creating a more aesthetically finished effect.

Carbon fiber front air inlet

The final carbon fiber element in this system is the front inlet—essential for directing atmospheric air to the channel and then to the filter.

The inlet is designed with a constant curvature radius for maximum efficiency in directing incoming air to the openings in the channels. This allows for maintaining the lowest possible inlet air temperature and increases the rate of inlet air temperature drop after the system is heated up during idle.

Individually crafted mounting brackets

To ensure a perfect fit, we dedicate a lot of time to developing mounts. Just like in all our intakes, the brackets are specially designed for a given application, and for the B9 RS4/RS5 system, the brackets are laser-cut from stainless steel and then powder-coated for durability. CNC-machined mounts are then attached to the brackets and pressed onto the factory rubber mounts used to secure the factory airbox. This ensures that our intake fits just as precisely as the factory system.

All components come together in the engine bay, creating a genuine improvement in the driving experience while also providing an amazing visual presentation of form and function in total harmony.