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Old 09-13-2012, 11:12 AM   #8
roger 04 rt
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Joined: Nov 2011
Location: Massachusetts
Oddometer: 2,363
Originally Posted by bigbadandugly View Post
[U][B] ...

The Long Story


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.


The PCV comes with a map for the stock GS. Fortunately DynoJet had a map on its website for a US bike with a full Akro system and stock air filter, so I grabbed that. Turns out it was almost a perfect map for my bike.

After the installation of the mods was complete, I took the bike for a spin. My Fat Ass dyno certainly noticed the power pick-up as soon as it hit 6,000 rpm. The first time I cracked it wide open throttle, the bike nearly ripped the handlebars from my grip. It is literally like somebody threw the nitro switch at the engine crested 6,000 rpm. What an amazing feeling!

This is about when we first noticed that the performance of the boxer engine was highly temperature dependent. The best runs came when the engine was in the "high four bar" range, meaning just before the oil temperature gauge moved to five bars. Runs at three bars were consistently about 10-12 rwhp low (i.e. in the high 90's). Runs at five bars were typically around 4-5 rwhp low of the highs. The optimum readings all came during runs when the engine had been in the four bar range for a bit, and typically in the second or third run (we typically did three runs whenever we made a change to ensure we eliminated any abnormalities.)


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).

Really interesting project thanks for providing all the information. I bet you're pretty pleased with the extra horses and better driveability. A couple questions and thoughts crossed my mind as I read through.

--Have you used the AutoTune capability yet? What's it like to use, how long did it take to dial it in?

--I see that the Dyno runs show data starting at 4000 RPM. Did you get any charts with data in t he 2000-4000 RPM range?

--I downloaded a map for the Akro system (attached below) I noticed that it adds a lot of fuel at half throttle. No real comment just found that some of the 25% additions are pretty big (if I'm reading it correctly). Also found it interesting that the L/R cylinders are pretty different.

--Regarding the best runs being just before it warmed up at 4 Bars, this may be at the tail-end of the warm-up enrichment and the BMS-K could be adding 3-4% to the fueling. If that's the case, you may get more performance warmed-up with some tweaks to the tables.

Thanks again for the effort to share all this.


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