The F8X M3/M4 Eventuri intake system was a culmination of months of dedicated design and development work. Here are some details of the development work and decisions which were made during the process:
A photo showing the final 3D printed prototype parts in place:
The aim as always was to develop an intake in order to make the inlet track of the engine more efficient therefore allowing the engine to make more power. To do this we had to carefully balance inlet temperatures requirements with a smooth path for airflow. Clearly lower IATs is best for power but then ensuring the inlet track is smooth is equally as important to allow the turbos to draw in air with as little drag as possible.
All our main components will be made from prepreg carbon fibre of the highest quality. We use CF because it is a great heat insulator across its thickness. We have seen other companies use Aluminium tubes etc which is a cheaper way of doing things but Aluminium is more than 400 times worse than CF at insulating the intake air from engine bay heat! So once the engine bay is heat soaked, metal tubes will get very hot and will heat up the inlet air as it travels through.
Filter Housings
The main component in our intake systems and the thing which sets us apart from other intake companies is our Venturi housing which is a unique take on the regular "cone filter with heat shield" design. It is a Patent Pending system where we reverse the cone filter to decouple it from the narrower inlet/MAF tube and the actual housing acts to then shape the airflow smoothly down from the large opening to the smaller outlet to the MAF.
Here's a diagram to summarise the advantage of the design:
With the housing design completed to fit into the F8X engine bay we then proceeded with the tubing which also hold the MAF sensors.
LHS Intake
Looking at the engine, the left side has a short convoluted pipe going from the OEM airbox to the turbo inlet tube. In order to use our intake housing, we redesigned the tube, removing the ridges and importantly holding the MAF sensor.
To direct ambient air to the filter, a duct was designed which fits over the stock intake duct from the bumper. Initially this was designed as a closed duct to completely cover the mouth of the housing:
However, CFD analysis pointed to turbulence caused by the abrupt change in direction from the stock duct to the filter - on dyno testing this was proven as we gained more power by opening the top of this duct.
So this was redesigned and now the duct directs and saturates the filter opening with ambient air without causing a restriction - a balance between IATs and airflow:
Although now semi-open, IATs are still kept consistently low with the front scoops which saturate the area in front of the filters with ambient air. More details on the scoops later.
Now since we have removed the flexible stock tube and replaced it with a rigid CF tube, we needed to ensure some movement in the assembly in line with engine rotation and vibrations. So a mounting bracket was designed to slot into the stock rubber airbox mount. The bracket has a stub at one end which sits in the rubber mount and allows for adequate movement:
RHS Intake
For the right side, we redesigned the long tube to go from our filter housing to the turbo inlet tube. This longer tube has to clear the top of the radiator fan shroud but stay under the stock strut brace. In order to do so, like the stock tube, we transitioned the tube from circular at the connecting ends to oval in the middle for clearance. Importantly, we maintained a constant cross sectional area throughout the length downstream of the MAF sensor. By doing so the airflow maintains a constant velocity through the tube and the smooth geometric transitions help maintain laminar conditions.
Again - a duct was designed to capture ambient air from the stock ducts and direct the flow to the filters. Just like the analysis and testing carried out on the left side duct, we found that by opening the top of this duct, the system gained more power. Again - our scoops then ensure cold air saturation at the filter mouth.
Front Air Scoops
The final components in this system are the front scoops - essential in our system to direct ambient air to the ducts and then to the filters.
The scoops were designed for maximum efficiency in directing the incoming air to the stock duct openings. Many aftermarket scoops have a large flat area almost perpendicular to the oncoming air - not great for channeling it into the ducts as the airflow just "hits" this flat portion and creates turbulence.
The Eventuri Scoops have been designed to sit directly behind the front grills to capture as much air as possible and with a continuous curve to the duct opening to ensure this airflow is efficiently channeled.
Here are the 3D printed prototypes in place - as you can see they capture the full area between the duct opening and the grills.
Full assembly photos:
With the design completed we then moved onto production from Prepreg Carbon Fibre using the same weave as the OEM BMW M Performance 2x2 weave. Dyno testing was also carried out as results can be seen in the performance tab above.