An ARM F30 Intercooler upgrade is one of the best modifications you can make to your 335i.  One of the F30 335i's most significant weak points is its stock intercooler.  This becomes obvious when tuning the N55 to increase boost with a Stage 1 tune and even more so with a Stage 2+ tune.  With a higher boost target, the charged air coming out of the compressor is hotter, therefore increasing IAT's.  To compensate for the higher IAT's the ECU (DME) reduces boost, timing, and overall power to the engine.  This is the exact opposite of what you want for getting your F30 335i to run faster.  In order to keep those IAT's low, a larger and more effective intercooler is needed.

CONSTRUCTION

The ARM F30 335i FMIC is the perfect cooling solution for any stock turbo or upgraded turbo N55 setup.  With an intercooler core size of 20x11x3" and an overall volume of 660cu in. the ARM F30 FMIC is 235cu.in. or 36% larger than the stock N55 intercooler which comes in at only 425cu in.  In addition, the ARM F30 FMIC utilizes an ultra-dense 14 fins per inch external core, giving it the best cooling performance possible. 

With a 220sq.in. face the ARM F30 335i FMIC has a 120% larger frontal area than the OEM intercooler with only a 100sq.in face, and 120sq.in. larger than OEM and 55sq.in./33% larger than most aftermarket F30 intercoolers.  Having a larger frontal area equates to more effective cooling compared to intercoolers of similar total volume.  In the milliseconds that the ambient air passes through the intercooler, it warms up, making the actual cooling less effective towards the rear of the intercooler.  Taking the area towards the rear of the intercooler and bringing it towards the front improves the overall ability of the FMIC to cool the charged air on the N55.  This is shown in our IAT testing results below.

INTAKE AIR TEMPERATURE RESULTS

Our baseline run was performed on a 335i running 16psi of boost with the stock F30 intercooler.   The 3rd gear run started at 93 degrees and ended at 126 degrees, a huge increase of 33 degrees Fahrenheit on 16psi of boost, and certainly restricting the amount of power this N55 could have been making.

After installing the ARM F30 FMIC there was a massive improvement in cooling performance that resulted in only a 2 degrees Fahrenheit increase in IAT. In this 3rd gear run with boost peaking at 18psi, which is 2psi higher than the stock intercooler run, it starting at 95 degrees and ended at only 97 degrees. This is a 94% improvement in cooling over the OEM F30 intercooler!

IN THE BOX