Eventuri BMW G29 Z4 M40i B58 Carbon Intake

BMW G29 Z4 B58

*Images shown with intake fitted to a Supra with the same engine. Carbon engine cover available separately.

Performance Gain: 17-20hp, 11-20ft-lb

Fitment: BMW G29 Z4 M40i

The Z4 B58 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.

Dyno Testing

Our intake has been independently tested by a US tuner on a B58 Supra with downpipe and tune. The tests were done back to back on the same day with only the airbox being changed for our intake system. As can be seen there is a performance gain for a large portion of the RPM range with some areas showing over 20hp gain. This is the result of derestricting the inlet path while maintaining low inlet temperatures by keeping a fully sealed system.

Dyno testing an open cone system with the hood open will yield gains but once on the road with the hood closed the heat soak will cause a significant detriment to the power with the open cone sucking in hot air which is a significant problem on the Supra since the intake is directly next to the exhaust manifold and turbo. . With higher air temperature being less dense, the turbo will not make as much boost resulting in lower power. Furthermore, once the car is accelerating and the open cone intake has pulled through the standing hot air present, they will continue to pull in the heat generated by the engine and turbos as they spool. With the engine under load and accelerating, turbos produce a lot of heat which can even be seen with the hot sides glowing red. This is why we designed our system fully sealed.