2004 R1150RT Wideband O2 Sensor Project

[roger 04 rt]

Someone asked me the other day to take a test ride with fuel pressure set to 52 psi, Motronic reset and in Open Loop mode (Wideband O2 sensor unplugged). I got out yesterday and made the run.

My report is simple, the bike runs great--smooth, good power, very responsive to throttle from 2000 RPM or so on up, even in 4th gear. A lot like the Closed Loop test rides at 52 psi and Wideband O2 set to 13.8:1. It's not really a surprise to me that it ran well in Open Loop. But I want to point out one thing: because I had the Wideband O2 installed, I knew that my setting of the fuel pressure was producing the enrichment I was looking for. Without the Wideband O2, you can crank up the fuel pressure, but you can't say for sure where you are with the enrichment.

If you go back earlier in this thread to here: Open vs Closed Loop, notice how much flatter the Closed Loop curve looks and how much tighter the histogram distribution of AFRs is in the smaller plots.

The same thing happened yesterday when I rode at 52 psi, reset Motronic, Open Loop. The range of AFRs, rather than being tightly centered on 13.8:1 where mostly around 14.3:1 and 13.3:1 (the two horizontal dashed lines in the plot below). My educated guess is that this is how the Motronic tries keep the Catalytic converter running even if the O2 sensor is dead. Normally in Closed Loop, with a stock sensor, the Motronic runs fueling a few percent above and below 14.7:1. (Snooze alert: The reason for going to the lean side of 14.7 is to allow Oxygen to recharge the Cerium in the three way converter.) So now, Open Loop the Motronic makes big moves in the fueling, still hoping to create a lean-of-14.7/rich-of-14.7 scenario. This way too rich/way to lean is a sort of limp-home-mode. (It's noteworthy that this will be how many PowerCommander and Techlusion curves would look if anyone plotted them.) I think it is very likely that this causes more fuel consumption than the Closed Loop case.

So here is the Open Loop 52 psi plot with all its "wildness".




My favorite configuration remains:
LC-1 set to 13.8:1 with Fuel Pressure boosted to 52 psi (for E10 fuel).

[roger 04 rt]

I've now logged about 500 miles on my add-on fuel pressure regulator (FPR) and LC-1 combo--no BoosterPlug or other changes to my stock R1150RT.

The LC-1 and FPR are tuned for a gasoline AFR of 13.8:1 using E10 fuel. The mileage includes almost 100 miles between 70 and 85 mph. Lambda on the LC-1 is now set to 0.94. And the fuel pressure regulator (FPR) is set to 52 PSI, correcting Open Loop for both the change in Lambda and the leanness of E10 fuel. As setup now, I would say that the Boxer engine is as responsive, smooth and powerful (for the bike's weight) as any engine I've owned. It's interesting to duck down below the windscreen between 60 and 80 mph in 6th gear, listening to the engine it's very comfortable at these speeds, powers and RPMs (3000-4000).

On the last series of Open Loop tests that I made, I attempted to set things up in the garage while on a conference call. Cradling the phone on my shoulder, taking the bike off the center stand and dodging some stuff piled on the floor in front of the bike led to a slow motion tip-over and a couple of deep scratches on the windscreen as it hit an adjacent bicycle. I've bought a Micro-Mesh kit and some coarser (320 & 600) sandpaper. That seems to be going pretty well. Scratches are gone, polishing it up.

When I have time, I'll take a look at all the speeds and RPMs where the Motronic is Closed Loop, at least as much as I can cover.

RB

[roger 04 rt]

I got out today with the GS-911 attached and a PC in the Top Case for a 100 mph run up a section of posted 50 mph highway that runs through a flat swamp nearby. I didn't get past fifth gear before running out of highway. I continue to operate at 52 psi fuel pressure and a mixture of 13.8:1 no BoosterPlug or any other modification to my '04 RT.

The idea was to see when and where the Motronic runs the Closed Loop program. I've got some charts coming but here are a few observations. Keep in mind that the max 95HP is at 7250 RPM.

--Closed Loop was operational at 100 mph (The engine seemed very smooth here)

--Closed Loop was operational in 2nd, 3rd, 4th gears at nearly 6500 RPM.

--Closed Loop was operational at 48 degrees throttle (80 degrees is wide open) going 100 mph

--In 3rd gear, while accelerating to 70 mph the Motronic was Closed Loop a lot of the time. Same in 4th gear to 90 mph.

--In 5th gear, WOT Motronic stayed mostly Open Loop from 65 mph to 100 mph. But as soon as I "relaxed" the throttle to about 3/4 open at 6400 RPM, Closed Loop kicked in. Amazing!

Given the amount of time and operating areas where the Motronic will enforce lean Closed Loop, I think it gets easier to see the advantages of mixture richening by using a Wideband O2 to shift Lambda from 1 to something less--0.94 in my case.

--At 6000 RPM & WOT the injector was on for 7.2 milliseconds. One revolution of the engine only takes 10 milliseconds at that RPM. At 7250 RPM (max horsepower) each revolution is only 8.3 mS. The injectors would be open 90% of the time!

(The air temperature was 90F today; had it been 20F the 7.2 mS injector pulse would lengthen to 8.1 mS. Were I to boost my fuel output using a -20C air-temp shifter on a 20F day, that pulse would lengthen to almost 8.6 mS. More than 100% on-time! Fuel pressure is a better method for boosting injector output (compared to IAT shifting or PCs or Techs) since it doesn't require the injector pulse to be lengthened.)

That's the raw data. I'll try and post a chart tomorrow after I've thought about it further.
RB

[rutard]

Roger, thank you for all the details and info you have posted in this thread. I am still trying to wrap my head around much of it, but it has certainly let some light into WTF is going on inside the Motronic brain.

Originally Posted by roger 04 rt

...Were I to boost my fuel output using a -20C air-temp shifter on a 20F day, that pulse would lengthen to almost 8.6 mS. More than 100% on-time!...

BUT, making conclusions about the efficacy of IAT shifters ( or other performance mods) based on their performance at temperatures well below freezing doesn't seem reasonable.

[roger 04 rt]

Originally Posted by rutard

Roger, thank you for all the details and info you have posted in this thread. I am still trying to wrap my head around much of it, but it has certainly let some light into WTF is going on inside the Motronic brain.

BUT, making conclusions about the efficacy of IAT shifters ( or other performance mods) based on their performance at temperatures well below freezing doesn't seem reasonable.

Thanks for the kind words. You're right about the IAT shifters, they should be judged on an array of merits, with measurements. The reality is that I may have made more GS-911 and AFR measurements than others. I think that WOT At redline RPMs is going to come close to overloading the injectors. But this is off track.

Many believe that Motronic Closed Loop works for small throttle andgles and up mid RPMs. The chart I'm going to show next will demonstrate just how much of the fuel table is covered by Closed Loop operation--nearly 50 degrees throttle and up to almost 7000 RPM and at 100 mph. The Motronic is reigning almost everywhere.

Next up, the chart.

[roger 04 rt]

I thought some might like to see the chart but I don't have time to provide the detailed annotation yet. Briefly, the Green line has two states: Closed Loop program running is the HIGH state but forget the label on the right side of the graph, it's just used to shift the 1/0 to the top of the chart. The red and blue curves use the left axis labels.

There are 6 RPM peaks. They are gears: 1st/2nd, 2nd, 3rd/4th/5th. I'll note them on the photo later when I get time for further detail but for now the comments in the prior post apply to this chart.

In first gear, Closed Loop seems to stop at 4000 RPM. In Neutral (not on the chart) Closed Loop ends around 3000 RPM, or maybe lower.

As I mentioned in the prior post, note that in 5th gear, 6350 RPM and 45+ degrees of throttle, the Motronic goes Close Loop!

[roger 04 rt]

How the Motronic handles spark advance has been something of interest. When the data in the last post was collected, I also collected ignition timing data, plotted below, for reference and for those who are interested. This data is for the Motronic MA 2.4, Pink Coding Plug.

Unlike fueling which can be modified externally, spark advance is under the control of the Motronic's internal program so can't be modified without an ECU chip replacement.

The charts below show spark advance compared to RPM and to throttle angle. In the RPM chart you can see that advance is increased with RPM, reaching a maximum of about 43 degrees above 4000 RPM.

In the TPS chart though you can see that the maximum advance is only for throttle angles below 18 degrees (80 degrees is WOT), and is then reduced for wider throttle angles. From 50 degrees to wide open throttle the advance is limited to 20 degrees.

The other thing worth noting is that while the spark is advanced with RPM up to certain throttle angles, there are a lot of points scattered well off the curve. This shows that there are other factors that the Motronic uses in its timing calculations.

[Drufus]

Originally Posted by roger 04 rt

I've now logged about 500 miles on my add-on fuel pressure regulator (FPR) and LC-1 combo--no BoosterPlug or other changes to my stock R1150RT.

As setup now, I would say that the Boxer engine is as responsive, smooth and powerful (for the bike's weight) as any engine I've owned. It's interesting to duck down below the windscreen between 60 and 80 mph in 6th gear, listening to the engine it's very comfortable at these speeds, powers and RPMs (3000-4000).



RB

At 75mph in 6th gear my 1150RT feels absolutely amazing, sounds great and it makes me want to run until the tank is empty! Just a great "feel" to the motor at this speed! I don't think I ever want own a bike that isn't a BMW boxer!

[Graminal95]

Keep up the great work. I really enjoy reading through your threads, and really like to see what the ECU is doing under what conditions.

[GS Addict]

Originally Posted by roger 04 rt

How the Motronic handles spark advance has been something of interest. When the data in the last post was collected, I also collected ignition timing data, plotted below, for reference and for those who are interested. This data is for the Motronic MA 2.4, Pink Coding Plug.

Unlike fueling which can be modified externally, spark advance is under the control of the Motronic's internal program so can't be modified without an ECU chip replacement.

The charts below show spark advance compared to RPM and to throttle angle. In the RPM chart you can see that advance is increased with RPM, reaching a maximum of about 43 degrees above 4000 RPM.

In the TPS chart though you can see that the maximum advance is only for throttle angles below 18 degrees (80 degrees is WOT), and is then reduced for wider throttle angles. From 50 degrees to wide open throttle the advance is limited to 20 degrees.

The other thing worth noting is that while the spark is advanced with RPM up to certain throttle angles, there are a lot of points scattered well off the curve. This shows that there are other factors that the Motronic uses in its timing calculations.

Interesting, I always knew that my bike had more power if I fed it the throttle going up a steep hill v/s cracking wide open. Thanks for all the great research!

[roger 04 rt]

Originally Posted by GS Addict

Interesting, I always knew that my bike had more power if I fed it the throttle going up a steep hill v/s cracking wide open. Thanks for all the great research!

Interesting point. At 49 degrees throttle there is 10 degrees more advance. I wondered about a second spring to increase resistance at 50 degrees.

The GS uses a different coding plug. I will have to use that some time and see how the advance plots.

[rutard]

Good stuff. These Spark-Advance/TPS/RPM graphs really get inside the brain of the Motronic.

Originally Posted by roger 04 rt

...Unlike fueling which can be modified externally, spark advance is under the control of the Motronic's internal program so can't be modified without an ECU chip replacement...

If this is true, would it make the GS's different coding plug irrelevant?

[roger 04 rt]

Originally Posted by rutard

Good stuff. These Spark-Advance/TPS/RPM graphs really get inside the brain of the Motronic.

If this is true, would it make the GS's different coding plug irrelevant?

Since the 1150 GS has different heads, cams and intake manifolds I believe there ARE differences in the VE (fueling) and Spark Advance tables. I plan to put a GS Coding Plug in my bike to see if there are any obvious Spark Advance differences.

What I was getting at with my comment is that I see several ways to adjust the fueling of the 1150 but I see no real way to adjust timing. Timing looks like a very dynamic matrix that you might change by swapping coding plug but not be able to effectively adjust by several degrees to a new value. For instance you can use a Wideband O2 to adjust closed loop fueling 4% richer or use a powerfommander to shift fueling but I don't see a way to adjust timing by 3 degrees at 5000 RPM with 50 degrees of throttle.

When I get a chance I will plot the 1150 GS plug. Then at least we will know the landscape.

It is also worth mentioning (even though I didn't plot it) that the dwell angle is very dynamic and changes somewhat differently from the advance curve. So the dwell time is variable based on TPS and RPM.

[k1w1t1m]

I for one, and I'm sure there are many others, that would love to see what the coding plugs do.

I know mine runs best on 91 octane gas, with the steptoe jumper, and it prefers the fancy plugs over the Autolite AP 3923s or whatever they are (single spark 2001). I suspect it is a bit richer with no CCP (which is how it came to me, I'm the second owner). It pings the same if I use mid grade gas whether I have the steptoe jumper on or not.

Thanks for all your hard work.

Tim

[rutard]

Originally Posted by roger 04 rt

...but I see no real way to adjust timing. Timing looks like a very dynamic matrix that you might change by swapping coding plug but not be able to effectively adjust by several degrees to a new value...

Have you seen Poolside's - Timing Adjustment How-to? It's not a dynamic change, but may allow you to shift the curve.

Keep up the good fight!