text: Dyno testing a '12 R1200GS with full Akro system with Power Commander | R1200GS Forum
  1) I did three stock runs and the best was 104 rear wheel HP ("rwhp") and 82 ft-lbs of torque (the other two were 103 and change rwhp). The best post-mod run was 111 rwhp and 86 ft-lbs of torque (with a number of 110's). There was one run that actually hit 112 rwhp but it was spikey above 7,000 rpm (unlike the other runs which were more or less smooth), so we eliminated it as an anomaly. These readings, and all the readings below, are "corrected" to a reference external temperature and humidity baseline for consistency.
  2) Of the 7 rwhp gain, about half was due to the Akropovic exhaust and the other half due to the Power Commander.
  I previously had a Moto Guzzi Stelvio that had similar engine performance issues caused by leaning fueling, and people raved about how the PC-V gave the bike a completely new character, so I knew that was a (expensive) solution to the first problem of low-RPM performance. However, through this forum I also because of the Booster Plug, which at $150 was a much more cost effective solution to the same problem, but did not address the 4200 rpm vibration issue. I had no urge to make this bike a track demon, so high-rpm horsepower gains weren't overly influential in my decision. Having time on my hands,
  I decided to splurge for the Power Commander in the hopes of adding additional power in the mid-range to hopefully drop the rpms below 4200 at my highway cruising speed of 120 kmh. I paid $520 for the R1200GS PC-V and AT-300 dual-channel Autotune device from Revzilla after a price match. The AT-300 has two O2 sensors so I could tune each cylinder independent of the other. The other advantage of the Power COmmander is that it enables you to have two maps, so I can set one map for every-day use (towards the power side in the non-cruise range) and second, leaner map to improve fuel economy on longer highway journeys. Creating the second map would be a snap with the Autotune.
  1) Akro exhaust with BMC filter, PCV disconnected
  2) Akro exhaust with BMC filter, PCV engaged and custom map
  I was a bit curious as to the impact of the high-flow BMC re-usable air filter over stock. I had read in a number of forums that there was no meaningful impact, but never saw any facts supporting this position. So we decided to pull the BMC and put in the OEM filter and did three runs. We did 108 and 109 rwhp runs, and followed these up with a 111 rwhp run, which became the new high of the day! One caveat here - when we did the runs after the filter swap, we didn't replace the fairing. This allowed the cooling fans to blow directly up the snorkel, possibly providing a "ram air" effect.
  I found this pretty conclusive evidence that "high-flow" air filters from K&N and BMC have little to no performance impact, but may still be worth buying as the re-usability factor will save you big bucks in the longterm. They are also beneficial as they allegedly continue to function when wet whereas paper filters break down. On the other hand, there are many posts in forums indicating that these high-flow filters are not recommended if you're doing significant dusty off-road riding because they tend to pass a lot of dust compared to the OEM paper filters
  We then began discussing the size of the filter and the narrow snorkel. The dyno operators noted that the GS air filter was the smallest they've ever seen, and also found that the long, narrow-entrance snorkel may compound the problem of the engine being air-starved. So we removed the snorkel completely, and just had the BMC filter sitting in the airbox (again, with the fans blowing into the air filter). We did two runs, both hitting 105 rwhp. We then surmised that snorkel design was an integral part of the engine design and not to be messed with!
  And with that my dyno session ended. I got my charts and rode home $350 broker.
  Here's the dyno chart of my best stock run contrasting against the best run with the mods (the one with the stock air filter).
  Reactions: sarkuch
  Great write up. Thanks for spending the time (and money!) on this. I know where I'm going to send people the next time the "air filter change for better performance" issue is raised.
  I did the same to mine (since sold) and it will remain the smoothest running motor I've ever owned. If a buy another GS in the future I will do the same to it.
  Past: too many Ducatis to list, a few Aprilias, a Guzzi Stelvio, a Husky, and some BMWs as well.
  A K&N filter should give you some hp boost.
  I kinda did the same on my 2008 R1200GS, only with a K&N air filter and a full front to back open BOS exhaust sytem, and i used a Rapid Bike instead of a power commander.
  I got to 117 Hp, but i'm not sure thats on the rear wheel (prob not).
  Im not an expert, but from what ive read it would be harder to get two dynos to read within 5hp with the same bike, than it would be to get two bikes within 5hp on the same dyno!
  What im trying to say is dont get hung up on figures from someone else. Dynoing bikes all over the world (or even in different towns) is not consistant
  Absolutely great write-up! Thanks for taking the time and sharing.
  It is really nice to see someone take the time and spend the money to do a methodical study like this and share it with everyone.