*Images shown with intake fitted to a Supra with same engine. Carbon engine cover available separately.
Performance increase: 17-20 HP, 11-20 ft-lb
Compatibility: BMW G29 Z4 M40i
The Z4 B58 Eventuri intake was developed to provide the turbo with a less restrictive flow path while maintaining low inlet temperatures. Heat and volume are the primary considerations when designing an intake for turbocharged engines. In the Z4, the intake system is positioned next to the exhaust manifold which heats up rapidly the engine compartment.
*Images shown with intake fitted to a Supra with same engine. Carbon engine cover available separately.
Performance increase: 17-20 HP, 11-20 ft-lb
Compatibility: BMW G29 Z4 M40i
The Z4 B58 Eventuri intake was developed to provide the turbo with a less restrictive flow path while maintaining low inlet temperatures. Heat and volume are the primary considerations when designing an intake for turbocharged engines. In the Z4, the intake system is positioned next to the exhaust manifold which heats up rapidly the engine compartment.
High temperatures are detrimental to engine performance as the turbo is expected to create boost with heated, less dense air and so the only way to ensure IATs are kept to a minimum is with a fully sealed intake. This however results in a restriction with only one stock air feed to draw air from. During development we noticed an additional opening in the wheel arch area and took advantage of this by adding a secondary feed to our airbox. Additionally, our sealed airbox also has a gold reflective heat shield to minimize radiative heat transfer from the exhaust manifold. To maximize 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 that also has a larger internal volume with an initial internal diameter of 111mm (4.4") that tapers gently downwards to match the turbo inlet. The tube provides a smooth path from the filter to the turbo inlet. Finally we use a custom high flow dry filter that is ISO tested for filtration performance and has a larger filtration area than the stock filter.
Dynamic Testing
Our intake was independently tested by a US tuner on a B58 Supra with a downpipe and tune. The tests were performed back-to-back on the same day, with only the airbox replaced for our intake system. As you can see, there is a performance gain across a large portion of the rpm range, with some areas showing a gain of over 20hp. This is the result of reducing intake path restrictions while maintaining low intake temperatures while maintaining a completely sealed system.
Dyno testing an open cone system with the hood open will yield gains, but once on the road with the hood closed, heat absorption will cause significant damage to power with the open cone sucking in hot air, which is a significant issue on the Supra since the intake is directly next to the exhaust manifold and turbo. With a higher temperature of air that is less dense, the turbo will not produce as much boost, resulting in reduced power. Also, once the car accelerates and the open cone intake has pulled out the hot air present, it will continue to suck in the heat generated by the engine and the turbos as they spool up. With the engine under load and accelerating, the turbos produce a lot of heat which can also be seen with the hot sides glowing red. That's why we designed our system to be completely sealed.
Another dynamometer test was carried out in the UK by Evolve Automotive with a downpipe and stage 2 tune. This dynamometer graph shows the difference between a completely stock Supra, then with the stock airbox, downpipe and stage 2 tune, and finally with the Eventuri, downpipe and stage 2 tune. All tests were carried out with the bonnet off. closed.
The Eventuri Z4 B58 intake system is made up of a series of components designed to perform a specific purpose and manufactured to the highest standards. We use 100% pre-preg carbon fibre with no fibreglass, which means we can achieve a smooth internal surface to maintain a smoother airflow. Here are the details for each component and the design ethic behind them:
Each intake system consists of:
Double carbon fiber airbox power
Made of pre-impregnated carbon fiber, The airbox has two purposes: to seal the filter from the heat of the engine bay and to provide a dual supply of cold air. Since the airbox is positioned next to the exhaust manifold, it is essential that the filter is completely sealed, so we designed the airbox to encapsulate the filter while providing a large internal volume. To seal the intake pipe we designed a laser cut plate with a rubber sealing strip that attaches to the airbox. The intake pipe passes through the plate and the rubber seal ensures that hot air does not enter the airbox. To further reduce heat absorption, there is an additional heat shield with a gold reflective layer on the exhaust manifold side that effectively combats radiant heat transfer.
Having a completely sealed airbox comes with the problem of having a restriction for cold air supply. The stock airbox draws air from a single duct that extends all the way 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 where the airbox sits. To utilise this feed we extended a scoop at the rear of our design which protrudes into the wheel arch and can also be seen after installation behind the front wheel. This second feed allows the turbo to draw from a larger area, therefore reducing restriction. As the scoop extends into the wheel arch area we also incorporated an internal splash guard to deflect water from the filter. The animation below shows both feeds and also the internal splash guard.
Our final consideration was for racing applications where our optional headlight duct is utilized for maximum cold air flow. We have incorporated a removable panel on the headlight-facing side of the airbox so that when the optional ducting is used, this panel can be removed for another direct feed of cold air to the filter.
Carbon inlet tube
The stock inlet pipe has a flexible, twisted section to provide movement to the engine. However, this also adds the possibility of turbulence in the flow path as there are more faces that can cause swirls. We replace this with our carbon tube which is smooth and also has a larger internal volume. Unlike most aftermarket intakes, we have maximized the size of our intake tube, the OEM inlet tube has an internal diameter of 80.8mm or 3.2" at the filter end. Our tube has an internal diameter of 109mm or 4.3". This equates to a whopping 82% increase in cross-sectional area over stock. The tube tapers gently towards the stock turbo inlet to ensure airflow remains as laminar as possible. The hose also has a CNC machined fitting for the temperature sensor and vent adapter. style="vertical-align:inherit;">Filter custom cone
Our Cone filter is made from a double layer non-woven mesh material and is ISO tested to ensure filtration meets OEM standards. The filter is cleanable and very stable at high temperatures with the urethane base material. The filter incorporates an internal flow guide cone to help the airflow converge while reducing the possibility of a stagnation point in the center of the filter space. The filter media has significantly more surface area volume than the stock panel filter.
