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Discussion Starter #1
Hey all,

I've been closely following the threads on the surge issues on the S2R1000 with 02 sensor. My new 07 S4R displayed similar problems in that 2-5000rpm range from the first mile. I switched to the full Arrow system at about 100 miles. The big question for most is to go with or without the 02 sensor. This afternoon, I decided to test a variety of combinations to see how they differ in terms of performance. My test isn't entirely scientific, but I did test these new combinations all back to back over the same 4 mile loop of smooth road at speeds between 25-50mph, with the same engine temp reading between 161-165 degrees (ambient air temp was 55). In all combinations, the bike ran well without surge above 5000rpm. In addition, all combos except for stock are with a 14T (minus 1) front sprocket.

To recap...
Completely stock: Started easily. Idled at 2000 rpm for the first 10 seconds, then settles into a rolling idle between 1200-1600 for the next 45 seconds. Once the temps switched from "low" to 105, the idle evened out at a constant speed between about 1100-1200 rpm. Partial throttle between 2000-5000 rpm had noticeable surge, and was hard to keep at a constant speed.

Arrow full, K&N with stock airbox, 02 sensor connected: Started harder than stock. Cold and warm idle just as stock. Partial throttle between 2-5000rpm displayed less surge than stock, but it was still noticeable and actually sounded more prominent because of the overall louder sound of the Arrow system. On occasion, the motor would also hiccup between 3-3500rpm. Probably 1 out of every 10 starts from a stop. As mentioned above, very strong above 5000rpm. (note: the Arrow pipes discolored considerably on the first long run. After cleaning with Simichrome and steelwool, they discolored more evenly and almost no blue with this combo)

Arrow full, K&N with top off airbox, 02 sensor connected: Started as easily as stock. Cold and warm idle just as stock. Partial throttle between 2-5000rpm displayed even less surge (almost completely gone), and the 3-3500rpm hiccup was gone. Power felt strong below 5000rpm, and as always, strong above. The fully open intake was obviously much louder. Overall the sound was very strong. At this point, the bike ran well enough to leave it alone. But the lure of the default mapping was calling.

Arrow full, K&N with stock airbox, 02 sensor disconnected, ECU in default mode: Overall, this combo ran very much like the one with the sensor connected and the airbox in place. Started hard and the 3-3500rpm hiccup returned. The surging and lack of power below 5000rpm returned also.

Arrow full, K&N with top off airbox, 02 sensor disconnected, ECU in default mode: Started as easily as stock. Cold and warm idle just as stock with temporary surge that disappears when temp hits 105. Partial throttle between 2-5000rpm displayed no surge, and the 3-3500rpm hiccup was gone. Power felt strong below 5000rpm starting at 2000rpm, and still very strong above.With this combo, I could cruise at 3500, 4000 and 4500 rpm with constant throttle and no surge or hesitation. It was the most ridable combo, and revs could dip below 4000rpm in slow turns with no concern of choppy throttle. I let the bike cool for 8 hours and restarted to check the cold start. Stared easily and idled at about 200-rpm, then settled back into the rolling idle until 105 degrees. Even ran very well below 5000rpm at 105 on the temp gauge.

Some conclusions: The airbox is VERY restrictive, and seems to be the consistent element in my surging issues. Also, as mentioned by many, the default mapping with the 02 sensor disconnected is pretty solid. The bike actually ran smoother below 5000rpm than my 2000 996 with Terms and DP ECU. The Arrow system actually seemed to help, especially when combined with the open airbox and 14T gearing. (BTW, the Arrow full system comes with a machined plug drilled for safety wire that replaces the 02 sensor in the collector). Given all that, I'm not sure I would spend the money on the PC3 given how well the bike runs in this combo.

One final question: Has anyone been able to reset the "check engine" light after disconnecting the 02 sensor? My short-term solution was to plug the light bezel with a simple cap plug from the hardware store (15 cents). The color and texture match perfectly, and it fits snuggly but can still be easily taken out. I've attached a pica to show it installed.

Hope this gives others the confidence to try the 02 sensor disconnected/ECU reset (disconnect the battery for 3-4 minutes) if you bike still runs poorly while Ducati or somebody works on a solution to the closed loop partial throttle mapping below 5000rpm. Joe X
 

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Nice work! Did you notice any difference in your temps?

I'm running the Arrow carbons with the Spark headers, stock airbox, & O2 sensor connected. I get easy starting, smooth idle & very smooth throttle with no surging. Still think it might be a little lean. Wondering if the default map would be better. Maybe I'll try it this week.

Interesting note on the Spark headers, with this setup the front cylinder connects to the lower can where as with the Arrow headers, the front cylinder connects to the upper can. Wonder what if any difference this makes? Sound, temp, power?
 

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Discussion Starter #3
GusDuc said:
Nice work! Did you notice any difference in your temps?

if the default map would be better. Maybe I'll try it this week.

Wonder what if any difference this makes? Sound, temp, power?
GusDuc: The temps stayed within a 4 degree window over the same 4 mile route. On the new S4R, the Arrow is technically a 2-1-2 system with a single collector where tthe 02 sensor mounts. With the race cans, this deepens the sound compared to my S2R that had the Arrow system with only a small 3" section where the pipes were slightly siamesed.

The easy thing about the default mapping test is it's simple and reversable. Not sure it's better for everyone, but worth a try if you're curious. Joe X
 

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Fortunately for me I was blessed with a solid s2r1000 I have had no issues with surging. I have replaced the stock exhaust with arrow cf cans and the bike runs awesome I feel like one of those Toyota commercials who can ask for anything more. Like gus I do feel the bike is running a little lean because of the exhaust at low rpms the bike really does not like it and starts to pop as it maneuvers through this east coast traffic. Anything above 4,000 rpms the bike is as smooth as a bald women's head. Thinking about doing the old reboot on the ecu to see if that makes a difference or wait until a pc is made available for the s2r1000. Nice work my man Kudos to you.

-ghost
 

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Discussion Starter #5
Bill in OKC said:
Hi grazi, thanks for your informative post. I should be getting the VDSTS package real soon so I can post on if it does the trick or not. Bill
Very cool Bill. Thanks for the info. Very interested to hear what you find. Joe X
 
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