Forge Induction Kit for BMW B46/B48 120i 125i 220i 230i 320i 330i 420i 430i FMINDK55

Step 1:  UK and some EU spec F chassis BMW’s have a blank which stops the low-pressure zone that builds up in front of the radiator from entering the inlet tract. We created FMINLD2, a carbon fibre sculped duct to replace the blank, and route more air into the tract towards the airbox.

Step 2: Now that this greater quantity of air has entered the airbox, we need a greater surface area of filtration to maximise the airflow towards the engine. Therefore, we decided on a high-flow performance cone filter and used our development of other upper airbox induction kits to inform our design process to create FMINDK55.

Step 3:The weak link was now the OEM inlet hose with its sound resonator and accordion ribs which cause turbulence and slow down the airflow. We created a multi-ply smooth silicone to significantly reduce turbulent airflow, and to handle tuned vehicles with ease.

We used SolidWorks CAD, 3D prints and numerous dyno sessions to truly unlock the power. Simulation testing played a large part in the design process to help maximise the airflow.

We were able to experiment with the airflow entering the chamber from the inlet tract into the lower airbox, by changing the position of the filter, the size and location of the louvres and other variables to ensure that the intake is maximising performance.

The 3D printed prototypes helped with comparing our simulation testing to real world driving conditions.

Using carbon fibre brings obvious benefits of strength, lightweight and aesthetics. However, a part that is often forgotten is its low thermal conductivity, which means it reduces heat soak and transmission of said heat to nearby items. Keeping Inlet Air Temps (IAT’s) low is often a difficult part of developing induction systems, so replacing metal or plastic inlet solutions for FMINDK55 will help decrease IAT’s and increase the volume of air supplied to your vehicles engine that is compressed by the turbo charger.

This has a better effect on performance when cool as this is to provide the engine with more oxygen (denser air), thus improving the combustion in each cylinder. In addition, by regulating and reducing the air temperature, it also increases the reliability of an engine by keeping the AFRs (Air Fuel Ratios) in each cylinder at a safe level, which in turn, can increase an engines power due to the air being cooler. A bigger bang is then created within the cylinder, providing the correct amount of fuel is added. This can equate to an increase in BHP and torque.

Testing was completed using Performance Remap in Gloucester with their VTEC 4 wheel drive dynamometer. This was to ensure all our data has been achieved with results as accurately as possible by an independent tuner. The results below speak for themselves, also with the added benefit of being a very easy component to fit with no specialist tools this is superb, affordable modification for the BMW enthusiast.

INDK55 picks up peak performance gains as well as smoothing out the curve throughout the rev range. Between 3500RPM and 3900RPM there is an increase of around 7NM, which is where the vehicle is happily in boost and utilising the increase of cold, de-restricted air.  This is at the exact point in the rev range where you will feel the punch of power, either in day to day driving when you’re picking up throttle, or at apex to corner exit where you get back on the power!

The BHP curve with FMINDK55 is smooth and consistent, with a slight increase in power that coincides with the 7NM gain discussed above. However, the most notable gain is from 5900RPM onwards, where there is a significant increase compared to stock. This increase shows a much flatter curve, rather than the drop shown by the stock setup where the engine effectively runs out of air. This is an increase of around 8BHP and lasts for 700RPM all the way to redline.

The M230i tested on the dyno was completely stock, but with a tuned vehicle you will see greater percentage gains as the vehicle will be able to utilise the large increase in volume of cold air.