Description

The B48 Eventuri intake has been developed to provide the turbo with a less restrictive flow path whilst maintaining low inlet temperatures. Heat and Volume are the main considerations when designing an intake for turbocharged engines. In the Z4, the intake system is located next to the exhaust manifold which rapidly heat soaks the engine bay. High temperatures are detrimental for engine performance as the turbo would have to build boost with heated, less dense air and so the only way to ensure IAT’s are kept to a minimum is for a fully sealed intake. This however, results in a restriction with only one stock air feed to draw air in from. During development we noticed an additional opening into the wheel arch area and took advantage of this by adding a secondary feed to our airbox. Furthermore our sealed airbox also has a heat shield with gold reflective to minimise the radiative heat transfer from the exhaust manifold. In order to maximise volume we made the airbox as large as possible with a recess for potential strut braces. The stock convoluted intake tube is replaced with a smooth carbon tube which is also larger in internal volume with a starting internal diameter of 111mm (4.4″) smoothly tapering down to match the turbo inlet. The tube provides a smooth path from the filter to the turbo inlet. Finally we use a custom made high-flow dry filter which is ISO tested for filtration performance and has a larger filtration area than the stock filter.

The Eventuri B48 intake system consists of a number of components engineered to perform a specific purpose and fabricated to the highest of standards. We use 100% pre-preg carbon fiber with no fibreglass which means we can achieve a smooth internal surface to maintain smoother airflow. Here are the details for each component and the design ethos behind them:

Each intake system consists of:

• Carbon Fiber Airbox with Dual Feeds
• Bespoke High Flow Dry Cone Filter
• Carbon Fiber Inlet Tube with 111mm opening ID
• CNC Machined Temperature Sensor Mount
• CNC Machined Breather adapter
• Heat Shield with Gold Reflective Backing
• Laser Cut Stainless Steel Brackets
• Silicone Coupler with OEM Specification Clamps

Having a fully sealed airbox results in the problem of having a restriction for the cold air feed. The stock airbox draws air from a single duct which extends to the front bumper area. During development we identified another area to draw cold air from which was a gap between the wheel arch and the chassis on which the airbox sits. To utilise this feed we extended a scoop at the back of our design which protrudes into the wheel arch and can even be seen after installation behind the front wheel. This second feed allows the turbo to draw from a larger area therefore reducing the restriction. Since the scoop extends into the wheel arch area we also incorporated an internal splash guard to deflect water away from the filter. The animation below shows both feeds and also the internal splash guard.

Our final consideration was for race applications where our optional headlamp duct is used for maximum cold air flow. We incorporated a removeable panel on the side of the airbox facing the headlamp so that when the optional duct is used, this panel can be removed for another direct feed of cold air to the filter.