It's well known that the N55 engines runs very hot. Turbos that build a lot of heat and a small radiator play into why this engine runs so hot. A quick look at your gauge cluster on your dash after a few minutes of "spirited" driving, you'll notice oil temperatures over 250 degrees. Considering that most cars don't even exceed 230 degrees tells you quite a bit. As oil temperatures get too high, thermal degradation occurs. This is when the oil starts to lose viscosity due to heat and start to break down and becomes more susceptible to "shearing" or oil breakdown. An internal combustion engine like the N55 engine, imparts high shear forces on the motor oil, which is sandwiched between two rotating or sliding forces under load and heat. "Shearing" is when the molecular structure is essentially torn apart by these mechanical shear forces. Lower your operating oil temperature will greatly reduce this. Thus your motor oil is in better shape to protect the bearings in your car's engine, thus improving longevity.
The M235i/335i/435i/M2 comes from the factory with a small oil cooler with a core size of 8.75"x4.75"x1" (222mmx121mmx26mm) which comes out to 41 cubic inches of core. The Sports Series Oil Cooler system features a large 11"x8"x2" (280mmx203mmx51mm) oil cooler with a core size of 9"x8"x2" (229mmx203mmx51mm). The Sports Series Oil Cooler comes out to 144 cubic inches of core which is 3.5 times larger than the factory unit each!
Type III Hard Anodize Black Finish:
The oil coolers come standard with no finish (silver color). Just like ER's other intercoolers, now offering them with the Type III Hard Anodize Black for those who want the stealthy look. With the Type III Hard Anodized finish, it is very hard to tell there is an aftermarket oil cooler on the car. Another added benefit of the Type III Hard Anodizing is that it makes the oil cooler fins harder and stronger, which makes it less prone to getting bent/damaged from road debris like rocks etc... ER opted for the Type III Hard Anodizing over the Type II color anodizing which is only asthetics for this purpose only (even though it cost us considerably more to anodize Type III than Type II). ER started using the Type III Hard Anodized Black finish on our rally car customer's FMICs years ago. Rally cars go through tremendous amounts of abuse and it was quite common to take hits on the intercooler from debris on the course. In fact after 1 event, often would see a large portion of the intercooler fins bent (killing efficiency) and fixing them after each event was quite tedious. After the Type III Hard Anodizing, a noticeable difference as there was considerably less damage. Even after hits and even accidents, the FMIC could take more abuse than before. Testing has shown no noticeable ill-effect from the Type III Hard Anodizing on performance (regular spray paint etc... has shown ill-effects on performance). Eventually, we started utilizing the same Type III Hard Anodize Black on ER's street cars and FMIC applications. It's only natural to offer the same finish for the oil coolers.