S2R 1000 Mufflers, Moto One Header Pipe and Lambda sensors - Written Feb ‘07
Summary: S2R 1000 demo bike fitted variously with Staintune slip on mufflers, Moto One cat replacement header pipe and open air filter. Lambda sensor connected and disconnected and a discussion thereof.
Note: ’06 USA spec S2R1000 run a different ECU to the ’07 USA, ’06 and ‘07 Euro spec S2R1000, all of which run the same part number ECU.
One of the problems when writing reports for these new closed loop models is that if I don’t actually know something there’s no one to ask, as the questions I want answered can only be directed at people hidden well within Magneti Marelli or Bosch. As such, it’s all trial and error with anecdotal evidence and speculation. And the problem with speculating is that you’re never quite sure if you’re (not) bullshitting and you really need to try something a few times with the same result before you can call it a truth.
And people who own the bikes often give reports of rather inconsistent behaviour that makes no sense, so it’s a bit of a minefield all round when you’re trying to sound like you know what you’re talking about. So if I say at this point I don’t know what I’m talking about that should help.
As an aside, the S2R 1000 ’06 and ’07 Euro and ’07 USA models share the same ECU. The ’06 USA model has a different part number. Don’t know why. Many US owners are complaining of surging, but we haven’t had anything too bad. This bike (our demo) does surge a little when you’re cruising along, but it’s fairly light albeit noticeable and still mildly annoying when you don’t ride it regularly. Like my R1100S, which surged somewhat, you get used to it as an owner. Although, like my BMW experience, the level of surging reported I suspect often has more to do with the rider or how the bike is used than the bike itself.
On to the bike. The engine spec for this model has not changed since the intro in ’03, regardless of what various press info says. It’s the same thing on all SS, M, MTS and Sport Classic models, with the exception of the wet clutch now being fitted to some. So we can happily compare this bike to the others we’ve dynod.
The only issue with this one is that the dyno appears to have picked up a different drum speed to engine RPM factor for the all std run, so all the (quite consistant) following runs don’t look as good if you do a RPM comparison. Not that there’s much in it. Also, all open air filter runs are just that std air filter with the lid removed. I didn’t have a DP filter kicking around to use for the tests. Well, actually, I didn’t look. I’m not that organised when I’m doing quick trips to the dyno.
First up is a road speed based power graph for the following combinations. All std is green. Staintune mufflers fitted is red. Staintune mufflers and open air filter lid is blue. Staintune mufflers, open air filter lid and Moto One header pipe is yellow. Staintune mufflers, open air filter lid, Moto One header pipe and disconnected Lambda sensor is pink. The runs end at the rev limiter, around 8,900 on this bike.
There are two things that stand out here. One is that the mufflers alone didn’t really do anything, which is a bit surprising, but the next point all the curves except the pink one are rather lumpy says a bit more about that.
The next graphs show the improvement the Moto One header pipe gives. The first graph is power with Staintune mufflers and std air filter lids, the second graph is power with Staintune mufflers and open air filter lids. Third is torque for the previous graph. As usual, green is before, red after. As you can see from the torque curve the cat replacement header pipe helps lift and hold the torque either side of the peak, although the actual peak improvement is not that great. The fact the mixture is too lean for max power will cloud the result somewhat, but the effect there should be somewhat consistant for both.
So why are all but the pink curves lumpy you ask? Well, the air/fuel curves show some more there. So far, none of the closed loop bikes have shown any indication they’re closed loop over the whole map. I wouldn’t have expected them to be. But the next graph (same as the previous one, except we’re looking at air/fuel only) makes me think that’s not the case. If you look at the lines, all except the Lambda sensor disconnected are fairly flat and around 14.7 or so. And there’s no way fitting mufflers, a header pipe and removing the airbox lid is going to make it run richer. Generally, when I see a result like this, I assume there’s something wrong with the dyno’s probe. But for the first two times we ran this bike all std and then with the Staintunes we ran the Aprilia RSVR immediately beforehand, and the result for it looked perfectly acceptable. So all I can say is, it appears this model runs closed loop all the time. And, that it has a very fast response to any mods you make. And a mixture over 14:1 will give a somewhat ratty curve on most things. For best power I’d want to see around 12.7 - 13.0 across the whole curve, so it’s definitely on the lean side power wise.
Next graph show the same air/fuel curves for 3 different Ducati closed loop models. Green is S2R 1000, red is S4Rs and blue is the Sport 1000, with all bikes being all std. As you can see, not all show the same consistant air/fuel around 14.7.
After I’d disconnected the Lambda sensor and run it I also disconnected the ECU and let the bike sit for a few minutes. This should have powered down the ECU and (speculation warning) cleared the adaption table. Not sure if I did it for long enough or not, but riding the bike afterward showed it to be noticeably different (not surging) when cruising. The WOT mixture didn’t change however. Green is Staintune mufflers, open air filter lid and Moto One header pipe. Red is Staintune mufflers, open air filter lid, Moto One header pipe and disconnected Lambda sensor and blue is with the ECU adaption table (allegedly) cleared. As you can see, the red and blue curves are identical.
To see how the power and then ECU would react to fuelling mods I added a Dobeck box. First up I ran without the Lambda sensor connected, just to see how much more power it made with more fuel, and to see what sort of air/fuel ratio it was happiest with. As usual with a Dobeck I did consecutive runs at settings 1 (no added fuel), 4, 7 and 11. The result is shown below, power first then torque and air/fuel. As you can see, the extra fuel helped down low, but not up top. Overall it would appear an air/fuel ratio of around 12.8 to 13 is where it’s happiest.
Then, without stopping the bike, I connected the Lambda sensor and ran again, with the Dobeck box still on setting 11. The previous (green) and next four runs (all run consecutively without interruption) are shown below for power and air/fuel. You can see the sensor input to the ECU made an instant change, but that change doesn’t appear to be moving with each progressive run as I expected. So maybe it’s not closed loop at WOT as I thought. You can see how the top end power responds to the leaner mixture too.
Then I wound the Dobeck back to setting 1 (no extra fuel) and tried that. Again, same result in that there seemed to be a sudden change without the further changes you would expect if it were closed loop. The previous run at setting 11 (green) and next three runs (all run consecutively) are shown below for power and air/fuel. The power clearly isn’t happy about the leaner mixture.
To end this last dyno session I unhooked the Lambda sensor again (between runs without stopping the bike) to see if we went back to where we had been previously. The next graph shows the run from the last dyno session (run 24, done a couple of months ago) being for the same bike setup, but with the sensor disconnected in green. The last two runs of this session are shown in red and blue red is sensor connected, blue is sensor disconnected. There is a little variation between the blue and green curves, but they’re very similar and show consistency in what happens when you disconnect the Lambda sensor.
The next graph shows where we started in green to the final result using two of the final session runs (red and blue) to give you an idea of what you could get if you tuned it properly. A nice improvement of the type generally expected. It’s also somewhat reassuringly about the same as one of the 1000SS I dynod a few years ago.
If we take the blue line out of the above graph and plot the green and red for speed against time you can see the clear increase in dyno roller acceleration with the mods.
So overall I don’t really know how the S2R 1000 ECU works with the Lambda sensor connected. I would have expected that any changes we made would have shown up in WOT dyno runs, but the consistency of the air/fuel trace says not. I have heard others comment on WOT tuning issues when running the lambda sensor connected, and from these results I can believe it.
I hope to trial and map the new idle motor control compatible Ultimap U59 ECU too, which will be available very soon.