2009 BMW 135i N54 vs. 2011 BMW 135i N55: Round 1

First I'll start with a little history. 

In the BMW 1 series enthusiast world the most debated subject seems to be what year of 135i to buy. For the US we got the 1 series starting in 2008. BMW had a beastly engine already developed to stuff in the small stubby chassis. It was a twin turbo charged, direct injection, 3 liter straight six that developed 300 horsepower and 300 lb/ft of torques (both under rated).

In 2011 BMW decided to switch the lump to the N55 engine that had been developed in 2009 and already doing duty in the 535i GT. This engine is rated at the same output, 300hp 300tq (Also under rated) but there are some key differences. First, the good. In addition to direct injection this version also adopted a technology referred to as Valvetronic. This is BMW's iteration of continuous and precise variable valve lift system. In combination with Double VANOS, continuously variable timing these systems allow for 15% improved fuel efficiency. Supposedly the N55 has less boost lag due to the twin scroll turbo design but I've driven both and I can tell you that's BS. Now, the bad. Because they went to a single turbo design it seems to be limited by the amount of air it can flow. This is evident on the dyno. Where the N54 starts slowly dropping off at high RPMs, the N55 crashes. This presents a problem when trying to get more boost.

Now the dyno runs

Mods:
2009 BMW 135i N54

• Burger Motorsports JB4 Tuner
• Injen Dual Cone air intake
• Berk Race axle back

2011 BMW 135i N55

• Burger Motorsports JB4 Tuner
• Burger Motorsports air intake
• Berk 4" catless down pipe
• Stock axle back

Baseline numbers were similar. I need to double check the exact numbers on the N54 but I believe they were slightly lower, especially in torque because the N55 was dyno'ed after the down pipe install. The baseline on the N55 with a downpipe was 289.6 hp and 301.0 tq. Once the tune was changed to map 2 the N55 put down 322 hp and 369 tq. Not bad, but...The N54 with stock catted down pipe on map 5 put down 343 hp and 370 tq.

N55

N54

The Race

Finally just the other day we got a chance to line them up, on a closed course with professional drivers...bwahaha. We both left some tire on the road in first but no smoke so I'd say we took off pretty well. The N54 pulled a slight lead. Near the top of 2nd gear the N55 started coming back. In to 3rd and the N54 lunged back ahead a few feet. Near the end of 3rd gear the N55 was pulling up to the door. We raced until the end of 3rd gear so about 110mph or so. It was so close but the N54 won by about 5 feet. This is the first time we ran them. Next Spring we'll be going to the drag strip to see what happens. I hate to make excuses but my N55 is still running worn out run flats. In the Spring I'll be getting new tires for sure. But then again the N54 may have down pipes and a larger intercooler too. We'll see. Videos will be taken for sure.