Evolution Racewerks Competition Series Oil Cooler Upgrade Kit for BMW N54/N55 135i/335i

Traditionally, oil lines would typically be routed so that the oil gets split to each of the oil coolers (each oil cooler handling 50% of the oil)  due to ease of building the system and lower costs.  Our Competition Series Twin Oil Cooler System however are setup in a "sequential" configuration.  What this means is that oil travels from one cooler to the other thereby 100% of the oil goes through both oil coolers.  Our testing have shown significant increases in efficiency and performance running a "sequential" configuration.  Our new CNC machined oil filter housing adapter (included in the kit) makes this possible.

Once ER figured out it was oil temperatures causing the limp mode, they went straight to work trying to solve the issue. Starting off first by adding a small auxiliary oil cooler in conjunction with the factory oil cooler.  This was a laughable attempt. This did absolutely nothing noticeable.  The next race, limp mode just like before.  On the next attempt, discovered that maybe the factory oil cooler just wasn't really efficient.  Thus, a new, larger unit would be needed. With the new oil cooler with the small auxiliary oil cooler, ER finally saw a slight drop in oil temperatures.  However, it wasn't much and again, at the next race, limp mode.  The next attempt saw ER building ducting shrouds to channel cold air to the oil coolers.  Again, this saw another drop in oil temperatures and better ability to fight off "heatsoak" but still, not enough.  The car would still limp at the track. Frustration was setting in. Many long days going to the track being ruined by limp mode. This was ER's 2008 race season.

 

With the 2009 race season looming, ER decided to go all out. Tired of limp mode. Tired of trying to get the car to do 1 lap under full power. Tired of finishing in the middle of the pack. This was when the twin oil coolers was born. ER scrapped the small auxiliary oil cooler and added an identical, larger oil cooler on the driver's side.  Thus, 2 large oil coolers, one on each corner.  The first race, everyone though ER was crazy running 2 large oil coolers; yet SUCCESS!  Oil temperatures had dropped significantly.  Now able to do more than 1 lap under full power. 

Yet, this was not the end of the limp mode journey.  Evolution Racewerks is located in Southern California and thus, they frequently see ambient temperatures over 100F.  The race tracks are also all located in the high desert region.  Perfect for some extreme testing.  Even though the limp mode issue was now under control with the twin oil coolers, on very hot days, it would rear its ugly head.  Also, on certain high speed tracks where the car would be at WOT for long periods of time, like Autoclub Speedway's oval configuration (think Nascar), occassionally limp mode would return.  Thus, ER spent the entire 2009 season refining the twin oil cooler system.  Originally, the oil lines were routed so that the oil split at the oil filter housing.  This originally started because of earlier attempts to keep the factory oil cooler.  Yet it dawned on ER that this was not efficient.  In essence, since the oil was being split in half, each going to one of the oil coolers, all the oil wasn't being cooled with both coolers.  Granted, it still worked since each cooler is now only charged to cool down half the oil in the system but it was inefficient.  Thus, it was necessary to devise a new system to run the oil lines sequentially to take full advantage of both oil coolers.  Oil now runs from the oil filter housing to the first oil cooler.  Then it runs to the second oil cooler and back to the oil filter housing. Basically, now 100% of the oil was going through both oil coolers.  With the new oil line system, a big change came race day.  The oil temperatures again dropped but what also changed was how much longer the oil cooler fought off "heatsoak".  Temperatures were more stable and stayed lower longer throughout the whole race session. And the best thing of it all?  This completely SOLVED the dreaded limp mode problem!  By the end of the 2009 race season, limp mode was a thing of the past. Regardless of temperature or track, ER NEVER again experienced the dreaded limp mode!