Eventuri Intake BMW G29 Z4 M40i B58 Carbon

Air Intake BMW G29 Z4 B58

*Images showing the installed air filter on a Supra model with the same engine. Carbon engine cover available separately.

Power Increase: 17-20HP, 11-20Nm

Fitment: BMW G29 Z4 M40i

The Eventuri air filter for the Z4 B58 has been developed to provide the turbine with a less restrictive airflow path while maintaining low intake temperatures. Heat and volume are the main factors taken into account when designing intakes for turbocharged engines. In the Z4 model, the intake system is located next to the exhaust manifold, which quickly heats up the engine compartment. High temperatures are detrimental to engine performance because the turbocharger would have to build pressure from heated, less dense air, so the only way to maintain minimal intake temperatures (IAT) is with a fully sealed intake. However, this leads to restriction, as there is only one factory air inlet. During development work, we noticed an additional opening in the fender area and took advantage of it by adding additional air intake to our air filter. Additionally, our sealed air filter has a heat shield with a reflective gold lining to minimize heat radiation from the exhaust manifold. To maximize volume, we made the air filter as large as possible, with a recess for potential stabilizer brackets. The factory corrugated intake pipe has been replaced with a smooth carbon fiber pipe, which also has a larger internal volume, starting with an initial inner diameter of 111 mm (4.4"), gradually narrowing to match the turbocharger inlet. The pipe provides a smooth path from the filter to the turbocharger inlet. Finally, we use a specially made high-flow dry filter, which has been ISO tested for filtration performance and has a larger filtration surface area than the factory filter.

Performance Testing

Our air filter has been independently tested by an American tuner on the B58 Supra model with a downpipe and tune. The tests were conducted directly after each other on the same day, with only the air filter being changed to our system. As can be seen, there is a power increase across a large part of the RPM range, and in some areas even exceeding 20 HP. This is due to unlocking the intake path while maintaining low intake temperatures by preserving a fully sealed system.

Testing on an open cone system with the hood open can yield benefits, but already on the road, when the hood is closed, heating of the air will cause significant power degradation because the open cone will be sucking in hot air. This is a significant issue in the Supra model, as the intake system is located directly next to the exhaust manifold and turbocharger. At higher temperatures, the air is less dense, resulting in lower compression pressure and lower power. Additionally, as the car accelerates, the open cone will still be sucking in hot air generated by the engine and turbochargers as they heat up. Turbocharged engines under load produce a lot of heat, which can even be seen by the redness of their hot parts. That's why we designed our system to be fully sealed.

Another dyno test was conducted in the UK by Evolve Automotive with a Stage 2 downpipe and tune. This chart shows the difference between a fully stock Supra model, then with the original airbox, downpipe, and Stage 2 tune, and finally with Eventuri, downpipe, and Stage 2 tune. All runs were conducted with the hood closed.

Eventuri BMW Z4 M40i B58 Kit

The Eventuri intake system for the Z4 B58 consists of several components designed to achieve a specific goal and made to the highest quality standards. We use 100% prepreg carbon fiber without fiberglass, which means we can achieve a smooth internal surface to maintain smoother airflow.

Each intake system consists of:

• Carbon fiber Airbox with dual inlets
• Specially designed high-flow dry cone filter
• Carbon fiber intake pipe with a 111 mm inner diameter
• CNC machined temperature sensor mount
• CNC machined evaporative adapters
• Gold reflective heat shield
• Laser-cut stainless steel brackets
• Silicone connector with OEM standard clamps

Dual Carbon Fiber Airbox

Made from prepreg carbon fiber with an impregnated finish, the airbox serves two functions - sealing the filter from engine heat and providing dual cold air inlets. Since the airbox is located next to the exhaust manifold, it's important for the filter to be fully sealed, so we designed the airbox to shield the filter while providing a large internal volume. To seal the intake pipe, we designed a laser-cut plate with a rubber seal that attaches to the airbox. The intake pipe passes through the plate, and the rubber seal ensures that no heated air reaches the airbox. Additionally, there is an additional heat shield with a gold reflective layer on the exhaust manifold side, which effectively combats heat radiation.

Having a fully sealed airbox poses a cold air intake restriction issue. The standard airbox draws air from a single duct that extends to the front bumper area. During development, we identified another area from which cold air could be drawn, which was the gap between the fender and the underbody where the airbox sits. To utilize this inlet, we extended the insert at the rear of our design, which protrudes towards the fender and may even be visible after installation behind the front wheel. This second inlet allows the turbocharger to draw air from a larger area, thereby reducing restriction. As it extends into the fender area, we also included an inner splash guard to redirect water away from the filter.

Our final consideration was the use of an optional headlight duct in race applications. We included a removable panel on the side of the airbox facing the headlight, so that in case the optional duct is used, this panel can be removed, allowing another direct cold air inlet to the filter.

Carbon Fiber Intake Pipe

The standard intake hose has a flexible and complex section to allow movement with the engine. However, this also adds the possibility of turbulence in the flow, as there are many surfaces that can cause swirling. We replace this with our carbon fiber pipe, which is smooth and also has a larger internal volume. Unlike most intake replacements, we maximized the size of our intake pipe, the standard intake hose has an inner diameter of 80.8 mm or 3.2" at the end of the filter. Our pipe has an inner diameter of 109 mm or 4.3". This means a huge increase in cross-sectional area by 82% compared to the standard. The pipe gradually narrows to the standard turbocharger inlet to ensure that the airflow remains as laminar as possible. The pipe also has CNC machined mounting elements for the temperature sensor and breather adapter.

Individual Cone Filter

Our cone filter is made of non-woven mesh material, which is double-layered and has been tested according to ISO standards to ensure that filtration meets OEM standards. The filter is washable and highly stable at high temperatures, with the base material being polyurethane. The filter features an internal cone-shaped structure to guide airflow towards the center, reducing the possibility of stagnation in the middle of the filter space. The filtering surface has a significantly larger volumetric area than the standard flat filter.