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Old 09-13-2012, 08:31 PM   #15
bigbadandugly OP
Gnarly Adventurer
Joined: Apr 2010
Location: Walnut Creek, SF Bay area
Oddometer: 423
I haven't had time to take the bike for a long ride to test the 4200 rpm shakes issue or to calculate the fuel economy. I'm not a big fuel economy aficionado on motorcycles, so I haven't take many mileage sessions to test fuel economy. I did calculate the mileage of two tanks of gas running a stock bike registered 42 mpg on both. The riding style was quite mixed for both rides - some highway, some back roads, some single track, etc. A very good "mixed riding conditions" ride.

And now to answer some questions:

Originally Posted by jdub View Post
I believe the above is mis-stated though, as the only way to change engine rpm for a given road speed is through gear ratios and not via engine performance.
Now that I think about it, my logic was ass backwards. My theory would be correct if I could have added a higher seventh gear!!!

Originally Posted by '05Train View Post
I take it you loaded a canned map and let the autotune module handle the VEs? Do you have any idea what the PC did to the target Lambda and spark tables? Also, the PCV adjusts timing the same way it adjusts target AFR/Lambda and VE; through offsets. I take it you didn't change them from the canned tables?
You can buy yet another Power Commander add-on that tunes in the ignition timing, but I gotta draw the line somewhere. I agree that if we had some spark timing flexibility we could have done a lot more. But time is money on the dyno and I was rapidly running out!

Originally Posted by Some Dude View Post
Also your dyno of choice is very generous as most dynojets around these parts put a stock R1200GS DOHC in the 90-94 rwhp stock with up to 104 after full Akra, PC V and Unifilter.
Now that you mention it, I do recall they had another R1200GS in that did mid-90s. Don't recall if it was a DOHC boxer or the predecessor. This would be consistent with what you said.

Originally Posted by roger 04 rt View Post
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?
This is a good question. We used the Autotune extensively in the tuning. In our first few runs we used the trace function and ran through as many of the cells as possible to get the Autotune to register a trim adjustment. Most adjustments were in the low single digits.

Afterwards we would focus on an area of the map to tweak. We would set a target AFR (i.e. make a group of four cells) either richer or leaner and then do a few runs to see the difference in output. We would then make tweak the cells depending on the dtno run and Autotune trim table.

Originally Posted by roger 04 rt View Post
--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?
Another good question that requires an explanation of the dyno process. The test run is done in third gear which they determine is the optimal gear so the run doesn`t last too short or too long (and some other reasons undoubtedly). They would get the bike at a steady speed (in this case 4000 rpm) and then go to wide open throttle (wot). The operators chose 4k rpm because they mostly tune sport bikes on the dyno and they would often bog down below 4k rpm in third gear, ruining your run.

At one point when we were trying to reduce the mid-range dip we postulated that the first bump at 4800 rpm way have been as a result of transients caused when cracking the throttle open at 4k rpm. So given the massive torque put out by the Boxer, we decided we could safely start the run at 3k rpm to see if it made any difference to the first hump. It did not so we went back to 4k rpm for the remainder of the tests.

Originally Posted by roger 04 rt View Post
--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.
Accurate observation, and the Autotune did not significantly alter this map. I postulate that the factory may really lean this section of the stock map out, probably because it plays a big part in the EPA test. I don`t think the EPA test hits the WOT range and therefore there isn't as much adjustment there. As well, when riders crack open the throttle to 100%, they want to (or expect to) accelerate rapidly and are less forgiving of hesitations, boggings, etc. Just my guess.
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