Behind the Speed: CSF Radiators

Keep Your Cool

Do you like going fast for extended periods of time? Are you making way more power than your car came with from the factory? Fancy turning your average grocery-getting BMW into a weekend track toy?

If you answered yes to any of these questions, a radiator upgrade should be at the top of your parts list. Don’t lie, we know you have a haphazardly organized list of your dream parts with their corresponding links and prices, just like we know you leave browser windows open with overflowing e-shopping carts without ever clicking “Check Out”.


Our project E90 335i is powered by the oh-so-lovely N54 3-liter twin turbo inline six. That’s right, two turbos and a cylinder layout that literally sucks when it comes to cooling. With a healthy 450hp, frequent trips to canyon roads and now, some of Southern California’s famous road courses, the little sedan the could, suddenly could not, after only a few laps. Once water and oil temps reach a certain threshold, the cars computer will save your ass by bringing power down to a whopping 50hp, which, as you can imagine, can put a real damper on fun-having or the attacking of time. Well, we got tired of this garbage, so we gave a call to our friends at CSF and ordered their Aluminum Radiator.


CNC stamped to guarantee it’s the real deal


There are a ton of benefits to this upgrade and literally zero drawbacks. CSF makes high quality products the exceed OE standards. Their radiators are all aluminum, meaning you can kiss your crappy plastic end tanks goodbye, which in itself will improve cooling by 25-30%. That right there is typically enough to keep this hot turbo monster out of limp mode on the track.


Well packaged to avoid damage during shipping


Direct Fit: The fact that this really is a drop-in unit, requiring no modifications, zip ties or bloody knuckles makes it a winner in our book. That’s right, the factory shrouding attaches perfectly, the inlets, outlets, brackets and mounting tabs are all CNC machined to guarantee everything fits, seals and works flawlessly. This kind of piece of mind goes a long way when you’re lapping a track at 100mph+, hundreds of miles away from home without a trailer. Yes, we might be dumb enough to do that. Daily driver, bro!


Data ist gut, yah? That oil needs cooling next. 


The radiator core itself is a 2-row 42mm unit with B-Tube technology. This design enables CSF to offer better cooling capacity and more surface area without adding weight. There’s a 15% increase in cooling capacity alone just by the increase in fin technology, which are precision multi-louvered to increase heat rejection performance and air contact. B-Tube technology sounds like a gimmick taken from a winter sports catalogue, but it’s the real deal. And would you guess it, B-Tube is exactly what it sounds like: most factory radiator tubes are “O” type, but CSF uses a specially engineered tube in the shape of a “B.” The tubes are carefully formed and then brazed over the seam seal, and CSF is able to use thinner and lighter aluminum because the “B” shape is actually stronger than a welded “O.” The tubes are made from aircraft grade special clad aluminum and are intricately formed on a high precision six-stage tube-forming mill. Too much info? Too bad! Do you know why I told you all of this? Because CSF is the ONLY aftermarket radiator manufacturer that uses this proven, badass process. They have raised the bar and set a new standard.


Precision fabrication with a polish to boot


We recently attended the KW Suspension “Shakedown” at Streets of Willow to get in some hot laps with our boosted sedan. Ambient temp was nearly 90* and there wasn’t a cloud in sight. The track was blasted with sunshine. Lap after lap, water temps stayed steady, never exceeding 230* F. If only we could say the same for our oil temps… but more on that soon!


 Each radiator is hand polished to a mirror finish

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