BMW is no stranger to the turbocharged engine. From their early introduction of turbocharged road cars to current LMP cars, BMW has proven their forced induction engine variants in the hands of commuters and top-performing racing drivers. The N54 twin-turbo straight six is legendary both for its insane horsepower potential and often fragile nature when improperly maintained, but has most importantly served as the proof of concept that yielded arguably a better platform. Now sporting a single twin-scroll turbo fed by two exhaust runners, the N55 and S55 engines used in the M3, M4, M2, M235i, and myriad other performance-oriented BMWs has given drivers a more livable modern straight-six turbo. Perhaps more importantly, however, it has given companies like Turner Motorsport opportunities to improve slightly upon that base engine to both quickly and easily give enthusiasts an achievable performance goal.
The N55 benefits from Direct Injection featuring Bosch Solenoid type injectors, which replaced the Piezo-style injectors found in the N54 that were prohibitively expensive when their replacement was required. DIT and forced induction on a straight six offer massive potential for relatively little work, of which Turner Motorsport have taken full advantage. Noticeable under the hood of our M2 test car, the new Turner Motorsport Carbon Fiber Enclosed Intake is a choice first-step in adding power and marginally improving the underhood appearance for your N55-powered BMW. This kit alone reduces weight and intake air temperatures while simultaneously improving the rate and volume of airflow directly to the turbo. Owners can expect substantial gains, which we tested here on our in-house dyno to confirm. Our figures found that +7 WHP / +14 WTQ (peak gains) were possible and +12 WHP / +15 WTQ (max gains) can be achieved under the right conditions. While this may not seem like drastic improvements, the already snappy throttle response characteristic of the N55 is noticeably more responsive and the additional WHP can be felt as the engine reaches peak boost. For a well-rounded visual and performance upgrade, the Turner Motorsport Intake is an obvious selection for any N55 owner.
Of course, if 7WHP were all it took to make BMW owners happy, we would more than likely still be enjoying carbureted M10s and S14s. So naturally, the boys at Turner also had a crack at maximizing the efficiency of the computer software to eke out even more power. Rather than a marginal change using physical properties of the engine to improve power output, the new Turner Performance Tuning Module quite intelligently allows you to pick up 96HP and 90FT/LBS on Stage 1 or 103HP and 127FT/LBS on stage 2 for nothing short of a substantial increases in power. Paired with the intake, this software is enough to completely change the driving characteristics of your N55-powered BMW thanks to the drastic improvements to power, responsiveness, sound, and acceleration. Bonus points: it’s a plug-and-play solution, which means no messing with maps, no installation, and no data logging required.
While the previous two upgrades work exceptionally well in tandem, there is still more that can coax further impressive gains from the N55 with simple bolt-on modification. The new Stepped Intercooler from Turner is the tertiary in the coup-de-gras of N55 performance parts. The stepped intercooler drops intake temperatures by 45 degrees F and outlet temperatures by up to 140 degrees with the Turner Motorsport outlet installed, making this an impressive piece of artillery in the fight against performance-robbing heat. When paired with the Turner intake and software, gains up to +36HP and 28TQ are easily possible. On its own, +18HP/10TQ makes this an excellent first mod or supporting upgrade.
For those of you keeping track at home, with the Turner Motorsport Intake, Software Module, and Stepped Intercooler, your N55 should be pushing 120+ more horsepowers than it did from BMW, all with the reliability and drivability left uncompromised thanks to the bolt-on nature of the parts and a conservative tune. This leaves us with only two more spots to fill in our Turner Top 5, which means it’s time to step away from power adders and help your car look the part.
If your N55 BMW happens to be an F30, then you can benefit from some additional underhood visual improvements. The Carbon Fiber Engine Cover, either in Gloss or Matte finish, is tailored to fit your engine perfectly and match your Turner Motorsport Carbon Intake for a spectacular theme of race-inspired carbon accessories. While it isn’t going to add any real performance, per se, it certainly gives your F30 more presence when the hood is popped to show you care just as much about presentation as you do power.
Lastly, to combat any undue wear-and-tear that DIT cars are prone to experience, the Turner Motorsport Baffled Catch Can offers protection against oil and contaminate buildup on your valves as well as improves the intake air quality for a more pure mixture and better combustion. Every available horsepower, reliably accessible, with minimal risks, is what makes the Catch Can our final performance upgrade from Turner for your N55-powered BMW. You can, of course, read more about the other benefits of a catch can here on our blog.
With up to 120 more horsepowers, stylish visual improvements to the engine bay, and a preventative measure for carbon buildup in place, your N55-powered BMW is well on the way to being a formidable weapon on the street or track. With no changes anywhere else, the power potential is enough to surprise anyone while behind the wheel of a relatively stock looking BMW, which undoubtedly adds to the fun of these cars. Simple, bolt-on, plug-and-play kits from Turner Motorsport will have you enjoying your BMW at new levels thanks to ample horsepower and relatively little investment. Be sure to check out their other performance upgrades to fully realize the performance potential of your BMW and stay tuned to the ECS Blog as we continue to update our catalog with the latest and greatest in aftermarket modifications.