Carbon intake system with secondary duct Eventuri EVE-B9RS5-CF-INT Audi B9 RS5 RS5

The Audi B9 RS4/RS5 Eventuri intake was developed to provide less restrictive airflow to the turbo while maintaining low inlet temperatures. The RS5/RS4 engine bay heats up very quickly, so simply having an open cone system would result in better airflow but higher inlet temperatures. We therefore completely redesigned the inlet path from the turbo inlet pipe to the front grille with a highly efficient sealed system. The restrictive stock airbox and flexible plastic inlet tube have been replaced with a venturi filter housing and duct system with smooth transitions. Additionally, by removing the convoluted stock inlet tube and replacing it with our one-piece venturi housing and solid tube, the airflow is much smoother as it enters the turbo inlet pipe. The resulting performance gains and aesthetics are industry leading for this platform.

The Eventuri B9 RS4/RS5 intake system is made up of a series of components designed to perform a specific purpose and manufactured to the highest standards. Here are the details for each component and the design ethos behind them:

Each suction system consists of:

• Carbon fiber venturi housing with integrated tube
• Generation 2 high-flow filter
• Carbon fiber intake duct
• Carbon fiber front air intake
• Carbon Fiber Secondary Duct
• High Quality Silicone Joints & OEM Spec Hose Clamps
• Laser Cut Stainless Steel Bracket
• CNC Machined Mounting Studs

Carbon Fiber Intake Housing Assembly

The filter housing consists of our bespoke second generation filter, carbon pod and integrated pipe. The carbon pod wraps around the reverse mounted filter and gently shapes the airflow up to the turbo pipe, which matches the turbo pipe in diameter. This is a key feature of the intake design, where we have eliminated the need for a convoluted rubber pipe between the intake and the engine. The filter housing and integrated tube extends to the stock turbo downpipe, and by mounting it to the engine, the entire filter housing moves with the engine. As the engine and filter housing move under acceleration, they are able to maintain a seal to the duct through the use of an expanding rubber extrusion that is mounted to the face of the duct.

This smooth reduction in cross-sectional area is reminiscent of the Venturi effect, where the airflow accelerates while maintaining laminar conditions. It can be thought of as a large velocity stack - below is a diagram showing how our patent-pending design compares to a typical intake system. Our custom filters aid the flow of air through the housings and allow for a smooth velocity profile as the airflow exits the housings. Further details can be found on the Technology and Filters pages. Carbon Fiber Intake Duct The duct directs ambient air from the scoop into the filter housing. It also creates a sealed volume of ambient air before the filter so there is a ready supply for the filter to draw from. The duct has been designed to make the most of the available volume in the engine bay. To ensure a good seal against engine bay heat, the duct also has a flexible rubber lip around the ports that press against the filter housing and the OEM front duct creating the desired seal but allowing the housing to move with the engine. To further improve airflow we have added a secondary port to the rear of the duct in the cold region of the engine bay. This geometrically complex piece is a key part of our B9 S4/S5 design. Carbon Fiber Secondary Duct For the full carbon fiber setup we have also fabricated the carbon secondary duct. This part connects the carbon main duct to the air inlet area on the slam panel. It eliminates the holes on the OEM part and blends in with the rest of the system for a more refined aesthetic. Carbon Fiber Air Intake The final carbon component in this system is the front air intake, which is essential for directing ambient air into the duct and then onto the filter. The air intake has been designed with a constant radius of curvature for maximum efficiency in directing incoming air into the duct opening. Allows you to minimize inlet air temperatures and increase the rate of IAT decline after the system has been subjected to heat during a shutdown.

Custom Bracket Work

To ensure a perfect fit, we spend a lot of time developing the mounting hardware. Like all of our air intakes, the brackets are designed specifically for the application and for the B9 S4/S5 system, the brackets are laser cut from stainless steel and then powder coated for durability. The CNC machined mounts are then bolted to the brackets and pushed into the stock rubber mounts that the stock airbox uses to attach to. This ensures that our air intake fits exactly like the OEM system.

All components come together in the engine bay to produce a genuine enhancement to the driving experience and provide an incredible display of form and function in complete harmony.

We've got an independent dyno chart showing the Eventuri versus the stock airbox on a B9 RS5. The car has had no other modifications. As you can see, power and torque are up across a wide portion of the rpm range. On the road this translates into more part-throttle and full-throttle response with the car pulling much more eagerly towards the redline. Testing was done on the same day back to back and temperatures were monitored to ensure consistency. The hood was closed for all races.

The gains are due to a combination of reasons:

1) The sealed system keeps IATs low, especially with the front intake forcing air into the system.

2) The venturi housing provides a smooth transition from the filter to the intake pipe without a twisted rubber section. This helps the turbo run more efficiently by maintaining laminar flow in the inlet runner.

3) The entire system is constructed from pure pre-preg carbon fiber which is great at insulating heat.