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Introduction and O2 Question


roger 04 rt

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More great data. Thanks.

 

Some first thoughts.

 

Not quite correct to talk about the maps as aiming for say, 14.7. The maps have their spritz durations but your measured A/F also depends on other factors which may or may not be close to the Factory parameters.

 

Zero crossings in a feedback system are not an essential or even meaningful property of the system but just a consequence of lots of other factors.

 

Booster Plugs and other foolers are a strange approach. Might be OK in some places that have very steady temperatures.

 

Ben

 

Hi Ben, Thanks for the feedback and thoughts.

 

When the Motronic/BMW engineers set that "spritz" of fuel, they had a hoped-for AFR target in mind it appears to me to be about 14.7:1 in the cruising range, which makes sense since that is where the O2 control program will toggle around. Your are right though that Battery Voltage, Fuel Pressure, Injector performance, etc. effect the actual AFR measured, as does Fuel Composition (e.g. E10).

 

Zero crossings of the O2 sensor are something that many (most?) ECUs monitor to conclude whether the O2 sensor and software are working correctly, hence why I showed the plot (also, DirtRider asked about it).

 

BoosterPlugs, as you know, shifts the AIT by 20C which effectively richens all Open Loop fuel "spritzes" by about 6% (confirmed by the tests I just made). For Closed Loop fueling, it effects the starting point used by the closed loop control program. In my application, I want the slightly richer Open Loop and also the shifted Closed Loop starting point. The BoosterPlug is a great choice since it shifts by 20C pretty linearly from 20F to 90F (measured in my test rides).

 

RB

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Comments: Pulling the Pink CAT Code plug definitely created leaner mixtures than with it in, by an amount I would guess was about 0.4 AFR leaner. I would not ride without Pink CAT Code plug installed.

 

 

Interesting.Back a number of years ago I almost holed a piston on my 1100RT. I was experimenting and had cut the signal wire from the o2 and had it connected to a cheap A/F ratio meter and had removed the Cat code plug.

 

We were on a group ride and really hammering it on a uphill mountain run when I noticed the A/F was getting very lean and at one point went completely off the lean side.

 

I backed off and let everybody pass and took it easy on the way home,where I pulled the plugs and found aluminum flecking on them.Looking at the piston tops revealed surface blistering on the piston tops. :P

 

Put the Cat code plug back in and never had the same problem.I would imagine normal riding would not have been an issue,but pushing it to the extremes puts it outside of the safe envelope

 

Yup, I've read so many post about richer mixtures with no CAT Plug and richer Limp Home Modes, that I thought I would just run the tests and see.

 

On my 04 1150RT, reset fuel tables are a bit leaner than 14.7 in the cruising range (maybe due to my running 7% ethanol fuel?) with the CAT Plug in and about 0.4 AFR leaner with it out.

 

My background is in the electronic Test and Measurement industry so I tend to think in terms of setting up tests and making the measurements when I want to know what's going on.

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Morning Roger

 

The thing that we all need to keep in mind is that you are working on an 1150 2 spark plug per cylinder head BMW with an Ma2.4 system. With 2 plugs per cylinder the open loop air/fuel ratio can be set a bit leaner than on the single plug models as that 2nd plug initiates better ignition at the outer edge. Even the spark tables are different on the twin spark.

 

The BMW 1100 (2.2 system) had a real open loop (only) fueling map available (no CCP) that didn't use an 02 sensor or catalytic converter.

 

 

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Morning Roger

 

The thing that we all need to keep in mind is that you are working on an 1150 2 spark plug per cylinder head BMW with an Ma2.4 system. With 2 plugs per cylinder the open loop air/fuel ratio can be set a bit leaner than on the single plug models as that 2nd plug initiates better ignition at the outer edge. Even the spark tables are different on the twin spark.

 

The BMW 1100 (2.2 system) had a real open loop (only) fueling map available (no CCP) that didn't use an 02 sensor or catalytic converter.

 

 

Hi D.R.,

 

You raise some good points. And I would emphasize that I have only run these tests on a 2004 R1150RT. For that model and for MA2.4, I think my results are fair and representative.

 

Also I have made the tests with the Pink CCP installed in almost all cases except the one noted in the post just above. There are some other MA2.4 CCP configurations. I took out the CCP because of the number of 1150 owner comments that I have seen where they've pulled the CCP "and thrown it in the trash". I wanted to get an idea what that would do to the fueling tables. My own belief is that the Bosch and BMW engineers are very good and I want to keep as much of what they've done as possible. The areas where they were challenged are fuel mileage and environmental compliance. 14.2:1 which is just a bit richer than stock (14.7:1, which is really Lambda=1 but who talks in Lambda terms) and it makes a world of difference in my 2004 R1150RT performance.

 

Regarding the MA 2.4 comments: Isn't it likely that they added the dual spark to reduce problems at 14.7:1 (O2 Closed Loop target) more than it was done to get even leaner?

 

Regarding the MA 2.2 and R1100: None of my tests have been made on that bike. It would not surprise me at all if there was a richer table in there. The best way to determine how much richer would be to ride around a test course (as you pointed me toward) with a Wideband O2 sensor and gauge. If I were to hazard a wild guess, and if I were them I would have made those cruising AFR targets in the 13.8 to 14.2 range, perhaps a bit richer.

 

I bet that for Closed Loop R1100s, a 13.8:1 target for an LC-1 implementation would yield a great-running, surge free motorcycle, but that is just an opinion.

 

RB

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Regarding the MA 2.4 comments: Isn't it likely that they added the dual spark to reduce problems at 14.7:1 (O2 Closed Loop target) more than it was done to get even leaner?

 

Yes, that illustrates what is wrong with targeting the lab-rated myth "14.7". 14.7 is too lean for single-plug Oilheads and maybe even a bit lean for dual-plug machines. They just don't burn as well as other contemporary (lean) machines and need a bit more gas.

 

Closed-loop using a narrow-band O2 sensor, you are pretty much obliged to target 14.7. But there is nothing special about 14.7. Your new gizmo (or the wide-band PCs) over-come that lock-step 14.7.

 

Ben

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Hi Guys -

Newbie to the oil head world. I've been following this thread with some interest. I have a new to me 2002 R1150RT single spark - yes, I know, worst of the surge offenders. I am in the process of completing an entire maintenance once over. The bike was babied, and is in great shape, however I am finding a few things that need remedied. I have felt the dreaded surge, and it is my humble opinion (after much research) that the bike runs too lean. We all know the reasons why. My bike does surge, and I believe that it can be made to about 90-95% surge free, I've done all the prerequisite, TB clean and balance, valves, autolite plugs, etc.

I've run the bike without the CCP, it feels smoother, but still surges and is anemic for sure. The question I have for those of you with more experience is:

1: Do you feel that simply pulling the 02 sensor cures the surge issue? Based on the research done in this thread, it would seem that this forces the bike into an open loop table - but richer. Is it enough though?

2: Is it not perhaps better, or have you had more success simply adding a techlusion, and setting it up to a richer fueling state with the O2 sensor in place? I this a better solution? I have a tehclusion Gen3 on the way.

 

Sorry if I hijacked the thread, but there have been many different options discussed and studied in this particular thread, that is why I asked here.

 

 

Thanks for your input.

Edited by steelerider
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Hi Guys -

Newbie to the oil head world. I've been following this thread with some interest. I have a new to me 2002 R1150RT single spark - yes, I know, worst of the surge offenders. I am in the process of completing an entire maintenance once over. The bike was babied, and is in great shape, however I am finding a few things that need remedied. I have felt the dreaded surge, and it is my humble opinion (after much research) that the bike runs too lean. We all know the reasons why. My bike does surge, and I believe that it can be made to about 90-95% surge free, I've done all the prerequisite, TB clean and balance, valves, autolite plugs, etc.

I've run the bike without the CCP, it feels smoother, but still surges and is anemic for sure. The question I have for those of you with more experience is:

1: Do you feel that simply pulling the 02 sensor cures the surge issue? Based on the research done in this thread, it would seem that this forces the bike into an open loop table - but richer. Is it enough though?

2: Is it not perhaps better, or have you had more success simply adding a techlusion, and setting it up to a richer fueling state with the O2 sensor in place? I this a better solution? I have a tehclusion Gen3 on the way.

 

Sorry if I hijacked the thread, but there have been many different options discussed and studied in this particular thread, that is why I asked here.

 

 

Thanks for your input.

 

Although our bikes differ in number of spark plugs, there is a lot in common--both are MA2.4 Motronics and they use the same CAT Plugs. Here is my 2 cents.

 

1. Simply pulling the O2 will not lead to a richer mixture. At some RPM/TPS points it may well be leaner based on the measurements I've made so far. When I pulled the CCP it was even a bit leaner. If you pull the O2 and add a BoosterPlug you will end up with a richer mixture and an AFR range of 13.5 to 14.5 in cruise. That may be rich enough but you may need to get a bit richer still. Can't really know without measuring.

 

2. I've studied the Techlusion but have not measured it. They do not say how the R259 version modifies the O2 sensor signal nor do they say how much richer the "pots" make the mixture. The O2 sensor connects through the Techlusion but it is not clear if it allows the Motronic to run closed loop. It seems you basically use your senses to decide when it is better. If you have it on order, why not try it? I didn't go that route because of their lack of a good explanation of what it exactly does.

 

Based on what I've measured on the '04RT an AFR of 13.8 to 14.2 should be able to make a surge free 1150.

 

My RT runs very strong while it is cold (1 bar or less on the RID) are you surge free while cold? The AFRs run between mid 13s and low 14s there.

Edited by roger 04 rt
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Regarding the MA 2.4 comments: Isn't it likely that they added the dual spark to reduce problems at 14.7:1 (O2 Closed Loop target) more than it was done to get even leaner?

 

Yes, that illustrates what is wrong with targeting the lab-rated myth "14.7". 14.7 is too lean for single-plug Oilheads and maybe even a bit lean for dual-plug machines. They just don't burn as well as other contemporary (lean) machines and need a bit more gas.

 

Closed-loop using a narrow-band O2 sensor, you are pretty much obliged to target 14.7. But there is nothing special about 14.7. Your new gizmo (or the wide-band PCs) over-come that lock-step 14.7.

 

Ben

 

Hi Ben,

 

Surely you are right about 14.7 being too lean for the 1150 bikes (single and dual sparks) given the hundreds of posts that can be found discussing the subject. There have been many fine mechanical solutions proposed to reduce the problem by "super tuning". Not too long ago I saw that some single spark owners are adding a second spark plug as a fix which seems kind of extreme to me.

 

My original idea was to find ways to enrich the mixture slightly for all modes and keep the Motronic fully functioning in both Open and Closed Loop.

 

(As a side note Stephen Mullen at Nightrider.com has produced a product that shifts the stock narrowband O2 for Harleys which need it for the same reason (surging) and also for the heating effect of the lean mixtures. He has several products and patents. He's a good guy and I keep in close touch with him but he doesn't see enough of a BMW market. In this video, he shows a simple install of an LC-1 on a Harley Harley LC-1 Install.)

 

So after fully mechanically tuning my R1150RT '04, a simple way of describing what I've done so far is:

 

1) Use a BoosterPlug to shift the Open Loop tables 6% richer across the board. The reason is threefold: E10 fuel needs a 3% richer mixture, to make the fuel tables richer when not Closed Loop, and give the Motronic a better starting point for the Close Loop search. The data I've taken indicates this worked.

 

2) Use an Innovate Technologies LC-1 to shift Closed Loop to 14.2:1 AFR. I may try a bit richer and a bit leaner at some point. But in doing the recent Open Loop rides I realized how much I like these new Closed Loop settings.

 

There is another cheaper way to shift the Closed Loop O2 which I will post in a minute but it takes some electronic design know-how and a way to measure the results.

Edited by roger 04 rt
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I'm new to this, so forgive my naive questions. As far as I can tell, the O2 sensor returns a voltage-coded signal that indicates the oxygen level in the exhaust and the ECU then uses this return voltage among other parameters to determine fuel injection timing and duration? With your programmable sensor, you are changing the transfer function between O2 and voltage such that the ECU is effectively fooled into thinking there is less/more (I'm not sure which) oxygen in the exhaust and adding more fuel than before?

 

If you were to take the O2 vs voltage plot of the old and new oxygen sensors and plotted them, would the shape of the lines be the same with a constant offset across the O2 range? (i.e. have you, e.g., lowered the voltage by .1 or whatever V for every O2 level?) Or is it more complicated than that? Could a simple circuit shift the voltage curve?

 

...

 

 

You've got the right idea on how a simpler version could be made. Here are some plots of appoximately how the stock Narrowband O2 sensor works:

 

nbest.jpg

 

The Motronic looks at the voltages coming from the stock narrowband sensor as it ramps fueling up/down, and switches in the vicinity of 450mV or about 14.7:1 AFR. You can see that it is not very temperature sensitive at that point which is a good thing.

 

If you wanted to use the stock sensor, you would have to design a circuit (probably with dual analog comparators and filters) that switched around 750-900mV and then produced an output centered on 450mV, offset by the voltage on the O2(neg) lead coming from the Motronic (about 140mV). This isn't too hard if you're an analog circuit designer but it would have the difficulty of needing temperature compensation.

 

All that considered, the BoosterPlug (which is fairly linear with temperature) and LC-1 seemed simpler and you get an AFR gauge included.

 

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Hi Guys -

Newbie to the oil head world. I've been following this thread with some interest. I have a new to me 2002 R1150RT single spark - yes, I know, worst of the surge offenders. I am in the process of completing an entire maintenance once over. The bike was babied, and is in great shape, however I am finding a few things that need remedied. I have felt the dreaded surge, and it is my humble opinion (after much research) that the bike runs too lean. We all know the reasons why. My bike does surge, and I believe that it can be made to about 90-95% surge free, I've done all the prerequisite, TB clean and balance, valves, autolite plugs, etc.

I've run the bike without the CCP, it feels smoother, but still surges and is anemic for sure. The question I have for those of you with more experience is:

1: Do you feel that simply pulling the 02 sensor cures the surge issue? Based on the research done in this thread, it would seem that this forces the bike into an open loop table - but richer. Is it enough though?

2: Is it not perhaps better, or have you had more success simply adding a techlusion, and setting it up to a richer fueling state with the O2 sensor in place? I this a better solution? I have a tehclusion Gen3 on the way.

 

Sorry if I hijacked the thread, but there have been many different options discussed and studied in this particular thread, that is why I asked here.

 

 

Thanks for your input.

 

Morning steelerider

 

On your "single spark" 2002 1150RT (the worst of the 1150RTs to get the surge out of), just removing the CCP will NOT drive open loop. Unlike the 1100 removing the CCP on the 1150 still allows the closed loop operation as long as there is an operational 02 sensor.

 

A (properly set up & adjusted) Techlusion will in most cases remove most of the light throttle steady RPM surging) as long as the fueling system is operating properly.

 

One of the issues with installing & using the Techlusion is getting it adjusted properly to remove the surge but still retain decent fuel economy. On the single spark 1150's that I have installed the Techlusion on the adjustment was critical & they didn't all respond the same.

What I do is temporarily mount the Techlusion in (plain sight) easy external access (not under the seat) then also run a remote fuse in place of the #5 (motronic) fuse (remove the #5 fuse & install a remote fuse holder in place of the fuse). That way I can easily remove the remote fuse to clear the Motronic's learned trim off-sets at every new Techlusion adjustment then do a new TPS re-learn.

 

Also, for the Techlusion to work properly on the 1150 it requires the stock 02 sensor to be healthy & working properly & the engine/fueling system to be in good condition.

 

 

Something else to try---- On the single spark 1150's I have also had decent luck in reducing/removing the surge by just disconnecting the stock 02 sensor & leaving the stock CCP (usually pink) in place then clearing the Motronic trim learn. Roger's data doesn't seem to confirm this on the later 1150 twins park but on the single spark 1150's I have done this on it made a noticeable reduction in the light throttle steady RPM surging. This also opens the door for adding an IAT or (Intake Air Temp) tuning resistance system (Like the Booter Plug) or a homemade resistance tuning system.

 

Some of the early 1150 single spark were REALLY bad for light throttle steady RPM surging & were not easy to get the light throttle surging out of.

 

If you have a stubborn one you might also try working with single electrode spark plugs in place of the factory dual electrode plugs then opening the electrode gap up to .035"-.040". That can help initiate combustion on the leaner light throttle F/A mixtures.

 

Also, verify a good base TB balance & clean throttle bores with clean BBS screw passages.

 

 

 

 

 

 

 

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If you wanted to use the stock sensor, you would have to design a circuit (probably with dual analog comparators and filters) that switched around 750-900mV and then produced an output centered on 450mV, offset by the voltage on the O2(neg) lead coming from the Motronic (about 140mV). This isn't too hard if you're an analog circuit designer but it would have the difficulty of needing temperature compensation.

 

In my experience with sports cars, it's very difficult to get a good AFR reading with narrow band O2 sensors. I suspect your simpler design will be more difficult to realize in practice.

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D.R,

Thank you for your excellent reply. I have done all the pre-requisite maint. Last night, I pulled the BBS screws and they were coated with junk, something I missed. They were cleaned and replaced, as well as the port. Injectors were also pulled and cleaned. Perhaps that will help. Will remote mount the techlusion 1332 as per your advice and add fuel as needed. It makes sense that if I add fuel where the bike needs, I will be able to tune out most of the surge. If the techlusion fails to work I will pull the 02 sensor and just ride the bike. The PO put 38K miles on it, so apparently it didnt bother him too much. Coming from my 2009 Triumph Sprint, I felt it right away - of course the Triple is one of the smoothest bikes I have ever owned. Appreciate your advice. I am assuming that pulling the 02 sensor forces open loop operation the whole time? I have yet to see that question answered in this thread.

 

Cheers.

 

Edited by steelerider
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I think removing/disconnecting the O2 sensor would also affect the gas mileage. Before that, try adjusting the TPS, easy to do. Also, try having it close to the 0.4V limit, I have heard that helps too.

 

My RT is close to yours, the way it is built I mean, and it does not surge at all. What are you using for TB sync?

 

Dan.

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D.R,

Thank you for your excellent reply. I have done all the pre-requisite maint. Last night, I pulled the BBS screws and they were coated with junk, something I missed. They were cleaned and replaced, as well as the port. Injectors were also pulled and cleaned. Perhaps that will help. Will remote mount the techlusion 1332 as per your advice and add fuel as needed. It makes sense that if I add fuel where the bike needs, I will be able to tune out most of the surge. If the techlusion fails to work I will pull the 02 sensor and just ride the bike. The PO put 38K miles on it, so apparently it didnt bother him too much. Coming from my 2009 Triumph Sprint, I felt it right away - of course the Triple is one of the smoothest bikes I have ever owned. Appreciate your advice. I am assuming that pulling the 02 sensor forces open loop operation the whole time? I have yet to see that question answered in this thread.

 

Cheers.

 

Back a few posts to 756667, all those measurements were with the O2 sensor pulled, which keeps the Motronic in Open Loop mode.

 

 

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If you wanted to use the stock sensor, you would have to design a circuit (probably with dual analog comparators and filters) that switched around 750-900mV and then produced an output centered on 450mV, offset by the voltage on the O2(neg) lead coming from the Motronic (about 140mV). This isn't too hard if you're an analog circuit designer but it would have the difficulty of needing temperature compensation.

 

In my experience with sports cars, it's very difficult to get a good AFR reading with narrow band O2 sensors. I suspect your simpler design will be more difficult to realize in practice.

 

I'm sure you're right. The results would not be easy to calibrate and would vary with sensor temperature.

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---- Before that, try adjusting the TPS, easy to do. Also, try having it close to the 0.4V limit, I have heard that helps too. ----

 

Afternoon Dan

 

That doesn't work on the 1150 with the 2.4 Motronic. The 1150 with the 2.4 uses a "learnable" TPS that learns the low & high threshold then assigns a base voltage.

 

 

 

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I think removing/disconnecting the O2 sensor would also affect the gas mileage. Before that, try adjusting the TPS, easy to do. Also, try having it close to the 0.4V limit, I have heard that helps too.

 

My RT is close to yours, the way it is built I mean, and it does not surge at all. What are you using for TB sync?

 

Dan.

 

Unplugging the O2 sensor might hurt mileage a little but the numbers I measured earlier in this thread suggest that the mixtures could easily be leaner than with the O2 connected.

 

My 1150RT didn't surge at all. What I wanted to find out was how well it would run with mixtures nearer Best Power levels (mid-high 13s). There is certainly more torque and better drivability even on a non-surging bike when you get the AFRs below 14.2.

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It would seem that disconnecting the 02 sensor to force open loop, and then adding a booster plug will the bike closer to an ideal mixture.

 

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It would seem that disconnecting the 02 sensor to force open loop, and then adding a booster plug will the bike closer to an ideal mixture.

 

It looks like that to me too. I might have gone that route but it does take the Motronic's ability to adapt to changes away when Closed Loop is eliminated.

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I pulled the O2 sensor tonight, got the bike up to temp, and the surging is just as bad (at operational temp.) This would support your data that the open loop is not a as rich as we would like to believe. By your data, it is only marginally better, and perhaps the effects of at are mitigated by E10 fuel. It would make sense that BMW would make an open fuel map that is very lean. There would be no reason for them not to. I would guess that they would try to get its as close to the closed loop mode. Even tried it with the CCP pulled - tiny improvement but not much. IncidentallyI had an older techlusion that I removed since I couldn't stand the manual pots (with screwdriver adjustment) and the bike ran much better with it on - which tells me that more fuel is needed, and the bike runs very lean in all modes. I have the newer version on the way, Will install, and turn up the cruise fuel.

 

I work in the diesel industry. We don't measure 02 levels as a form of fueling adjustment. We look more at input parameters (boost pressure, ambient temp, engine temp, air intake temp, coolant temp) rather than an output parameters such as 02 levels in the exhaust. Much better way of doing things IMHO.

 

Thanks for your very detailed analysis. It has been very useful. It seems like you have also come up with a solution that works.

 

 

 

Edited by steelerider
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I can't recall seeing any /2 boxers with dual plugs but it sure was common on the Airheads from 1970 on. Airhead owners were hopeful the 4-valve Oilheads with a central plug would be great, Odd that the Oilheads still benefited from dual plugging.

 

Charts I've seen of O2 sensors show more gradual transition than Roger's chart. These are not active devices (please correct me here) and so their voltage behavior is based on their chemistry.

 

Roger is quite right that it would be a simple matter to boost the O2 signal with an op-amp in-line to the ECU. Just scaling it and without temperature compensation is pretty simple with a four-wire circuit to the O2 sensor.

 

Rich A/F will destroy the cat converter. I suspect there are no cat converters out there on Oilheads that are working at this point in time... or on any sport bike. Silly to use a cat converter unless you have a sophisticated ECU too, not a Motronic.

 

While nobody can argue with Roger's evidence about the Booster Plug and similar gizmos, just seems inelegant to crow-bar the ambient temp signal that way.

 

Sharp pointy tiny permanent never-changing iridium plugs are really great on an Oilhead - saves money on plugs and prolly on gas too. Multi-electrode pretty daft. Be sure to use copper anti-seize since you may not be looking at them again for a lot of years.

 

Ben

Edited by Peter Parts
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...

 

Charts I've seen of O2 sensors show more gradual transition than Roger's chart. These are not active devices (please correct me here) and so their voltage behavior is based on their chemistry.

 

...

 

Hi Ben, I always look forward to your feedback since my experience is limited to the one model that I've been taking data on.

 

You're right about the narrowband O2 sensors. There are no transistors or active electronics. Oxygen chemistry causes them to produce a voltage which is measured by the Motronic as part of the Closed Loop control program. Here is a good description by Bosch of its O2 Sensors.

 

The O2 sensor chart I picked was simulated but I chose it to show the temperature sensitivity. The main point of the chart is to show how hard (not impossible) it is to shift the stock sensor away from 14.7:1 and why something like the LC-1 is better for shifting the AFR. Below is Bosch's actual chart.

 

I've read a lot and can't find anything that suggests a slightly rich mixture destroys the catalytic converter. A mis-firing engine that leads to a rich mixture can wreak havoc though. In the first case the exhaust has some unburned fuel but no oxygen so the cat doesn't overheat. In the mis-firing case there is both unburned fuel and a lot of oxygen (because the mixture didn't ignite in the cylinder), when it hits the hot cat it burns, eventually permanently damaging the cat. I have tried to understand this because of concerns about what the 14.2:1 ratio I'm running would do to the cat. (Of course Techlusions and Powercommanders also produce rich mixtures.)

 

Like you say on the 1150s and 1100s, the cats and O2 sensors are pretty old. One does wonder what they're doing at this point.

 

boscho2.jpg

Edited by roger 04 rt
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I took this scope shot from the terminals on my car's oxygen sensor. I was traveling at 60 mph, on a relatively flat road surface. This is the real time behavior of the sensor. I am guessing that the computer filters out this signal to provide a smoother control of the gas/air mixture.

5882.jpg.8e02b9c67da30351244102e759c21111.jpg

Edited by TeSmSp
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I've read a lot and can't find anything that suggests a slightly rich mixture destroys the catalytic converter. A mis-firing engine that leads to a rich mixture can wreak havoc though. In the first case the exhaust has some unburned fuel but no oxygen so the cat doesn't overheat. In the mis-firing case there is both unburned fuel and a lot of oxygen (because the mixture didn't ignite in the cylinder), when it hits the hot cat it burns, eventually permanently damaging the cat. I have tried to understand this because of concerns about what the 14.2:1 ratio I'm running would do to the cat. (Of course Techlusions and Powercommanders also produce rich mixtures.)

 

I spoke with one of our staff engineers today about a rich mixture possibly damaging a CAT. He suggested that in fact the opposite is true. A lean mixture burns hotter and is much more likely to inflict damage than a rich mixture that essentially burns cooler. As far as soot and carbon buildup, even at a richer burn the CAT still has plenty of heat to work effectively. He noted that has has seen damage from a coolant or severe oil leak into the engine which plugs the face of the brick and can start a combustible condition.

 

I have yet to read of a CAT being damaged by a richer mixture.

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I took this scope shot from the terminals on my car's oxygen sensor. I was traveling at 60 mph, on a relatively flat road surface. This is the real time behavior of the sensor. I am guessing that the computer filters out this signal to provide a smoother control of the gas/air mixture.

 

Great photo, thanks. I would love to get a scope hooked up to my motorcycle.

 

Looking at schematics and write ups, there are both analog input filters and digital switched-capacitor filters that pre-condition the O2 Sensor input to the Motronic Closed Loop program.

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I took this scope shot from the terminals on my car's oxygen sensor. I was traveling at 60 mph, on a relatively flat road surface. This is the real time behavior of the sensor. I am guessing that the computer filters out this signal to provide a smoother control of the gas/air mixture.

 

Again, I (and I am sure, many others) appreciate the data.

 

But what the curve shows is the sensor output while operating inside a feedback loop. It is the ECU that is initiating the switching by toggling the spritz in whatever increments Bosch thinks best, not the O2 sensor. The O2 sensor kind of amplifies the effect due to the pretty steep slope, but it isn't the reason for the all-or-nothing pattern.

 

Feedback is a challenging topic. You usually need to consider phase angle, system gain, bandwidth, and other electronic terms to think productively about feedback. BTW, aged O2 sensors get slow - and that screws up the feedback system.

 

As I poorly understand it, when you stuff carbon into a cat converter, it has to burn if off and the more carbon the hotter.

 

Now, I often insert the word "sport bike" into my posts (like the name of this forum) intentionally. Roger, as ever cogently, points out design A/F (whether by map or by feedback) should never be too far from stoich. True, but any time you blip the happy knob, you are dosing the cat converter with carbon and there are many instances while riding along when there's a lot of unburnt stuff passing into the cat converter... in sporty riding. For that very reason, modern cars with modern ECUs and 6 O2 sensors before and after the cat converter don't ever let this happen.

 

BTW, being stupid about acceleration is one major shortcoming of the Motronics. A shortcoming the CV carbs on the Airheads did not have.

 

Ben

 

Edited by Peter Parts
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I spoke with one of our staff engineers today about a rich mixture possibly damaging a CAT. He suggested that in fact the opposite is true. A lean mixture burns hotter and is much more likely to inflict damage than a rich mixture that essentially burns cooler. As far as soot and carbon buildup, even at a richer burn the CAT still has plenty of heat to work effectively. He noted that has has seen damage from a coolant or severe oil leak into the engine which plugs the face of the brick and can start a combustible condition.

 

I have yet to read of a CAT being damaged by a richer mixture.

 

Yup, a rich mixture quickly depletes the CAT's stored O2. Once it is depleted there is no O2 in the CAT or in the exhaust stream to oxide the unburned HCs or CO. No oxidation no heat.

 

However, when an engine is misfiring you have unburned HCs and Oxygen and the CAT can get very hot. A misfiring engine can be very hard on CATs.

Edited by roger 04 rt
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Pleased to say I installed the Techlusion 1332 today. No surging at all. Bike is running so much better with a richer mixture. The techlusion does add fuel in closed loop mode. I will likely watch my fuel mileage suffer. No big deal.

I found that there stock cruise mode setting -green ( 1 ) was still not enough. I have it turned up to 4.5 and the it runs very well. I finally feel that I am riding the bike that BMW intended this to be. Cat code plug is installed. I like that the Techlusion works with the 02 sensor. Accelerator pump, and top end fuel are at stock settings. Still running autolite plugs. It started today at 37 deg f and idled right away. Will be nice to be able to concentrate on actually riding for once. Thanks for all your data Roger. I feel like the techlusion is a little easier than your mod though. Cheers

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Pleased to say I installed the Techlusion 1332 today. No surging at all. Bike is running so much better with a richer mixture. The techlusion does add fuel in closed loop mode. I will likely watch my fuel mileage suffer. No big deal.

I found that there stock cruise mode setting -green ( 1 ) was still not enough. I have it turned up to 4.5 and the it runs very well. I finally feel that I am riding the bike that BMW intended this to be. Cat code plug is installed. I like that the Techlusion works with the 02 sensor. Accelerator pump, and top end fuel are at stock settings. Still running autolite plugs. It started today at 37 deg f and idled right away. Will be nice to be able to concentrate on actually riding for once. Thanks for all your data Roger. I feel like the techlusion is a little easier than your mod though. Cheers

 

Really glad the data helped you get a good result. The Techlusion is a different approach, an output modifier. It is easier to install but harder to know the AFR you've ended up at. Do you understand how it can close the loop and add fuel. They don't explain that and it's a contradiction. Perhaps they close the loop only under limited conditions.

 

Edited by roger 04 rt
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Roger,

It does intercept the 02 sensor to the ECM. So I assume that is how it knows when closed loop mode is engaged. It is also in full control of the inectors. Essentially, all it does is hold the injector open a little longer - and thus more fuel. On the new unit, you can actually adjust the switch point where the closed loop mode engages (by RPM)

I'm not an engineer, but I can tell you that it is very effective.

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My best guess is that you attach the O2 sensor to the Techlusion just to keep the connector from banging against the tank. Otherwise, the Techlusion is mostly just a smart spritz lengthener piggy backing on the ECU map.

 

The Techlusion might be piggy backing in the closed-loop mode too but I have good reason to think the T. folks prefer not to have that pesky closed-loop mode come into action (since they told me that one day long ago).

 

Ben

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Roger,

It does intercept the 02 sensor to the ECM. So I assume that is how it knows when closed loop mode is engaged. It is also in full control of the inectors. Essentially, all it does is hold the injector open a little longer - and thus more fuel. On the new unit, you can actually adjust the switch point where the closed loop mode engages (by RPM)

I'm not an engineer, but I can tell you that it is very effective.

 

I saw that it intercepts the O2 and your explanation has filled in a gap for me. By limiting the times when closed loop is possible, they can add fuel in Open Loop over more of the performance range.

 

During the times when it is Closed Loop, the Motronic will negate any additions that the Techlusion tries to make since the definition of closed loop is that the Motronic is varying the pulses (and any additions) around 14.7.

 

My best guess is that you attach the O2 sensor to the Techlusion just to keep the connector from banging against the tank. Otherwise, the Techlusion is mostly just a smart spritz lengthener piggy backing on the ECU map.

 

The Techlusion might be piggy backing in the closed-loop mode too but I have good reason to think the T. folks prefer not to have that pesky closed-loop mode come into action (since they told me that one day long ago).

 

Ben

 

It is pesky to what Techlusion does. Believing that steelrider is right, they found a way to maintain some co-existance.

 

I've started to log real-time LC-1 data and took a ride this morning after the motorcycle warmed up. The plot below gives an idea of just how well the LC-1 can hold the 14.2 target I've programmed it to. This tight band is because the LC-1 approach keeps the Motronic fully "in the loop".

 

It's also interesting to see spread on a normal ride--most of the points between 12.9 and 15.1.

 

I'll add some more charts over the next couple days when I get better at using that capability.

 

14.2histogram.jpg

Edited by roger 04 rt
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I beleive the answer lies in the fact that the techlusion actually does modify the input signal from the 02 sensor to the ECM - very similar to your method Roger.

It also then has control over injection duration, and is able to enrichen the mixture. So it seems to be a two part process:

1: Modify 02 signal

2: Control injection duration.

The rest, is magic jooojoo.

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I beleive the answer lies in the fact that the techlusion actually does modify the input signal from the 02 sensor to the ECM - very similar to your method Roger.

It also then has control over injection duration, and is able to enrichen the mixture. So it seems to be a two part process:

1: Modify 02 signal

2: Control injection duration.

The rest, is magic jooojoo.

 

It's very hard to shift a narrowband O2 sensor and keep it stable--modify, yes, shift perhaps. And if they did shift the O2 sensor, and keep the Motronic in the loop, the Motronic would be able to add the fuel. So I'd agree to "similar" in the way a cat is similar to a tiger. ;)

 

The joojoo is interesting. Since the Tech doesn't intercept the Fuel Injector (but rather hangs on) and doesn't connect to the TPS, what it does is create a pseudo TPS signal by measureing injector pulse width, it gets RPM information from injector repitition rate--what they call "load based technology".

 

As a class, the output modifiers (Powercommander and Techlusion) take the Motronic out of the loop. Input modifiers like Nightrider.com, BoosterPlug, Zeitronix or LC-1 sensors let the Motronic do what it was designed to.

 

I've got some interesting slide coming in another post soon.

Edited by roger 04 rt
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It has only recently dawned on me that in addition to logging samples with the GS-911, the LC-1 wideband sensor is able to log high-speed real-time AFR data. Here is a plot from a ride I took today, Closed Loop AFR still set at 14.2:1.

 

Some things I would note:

 

--During the first 2:40 the Motronic is Open Loop and the mixture is richer than 14.2, and climbing. At that point, it goes Closed Loop and the line holds 14.2 for most of the time.

 

--The Motronic is quickly richening the mixture during acceleration. The dips in the plot correspond to me turning the throttle. The AFR can, during "normal" acceleration (part throttle), get as rich as 12:1

 

--The LC-1 is very effective at returning quickly to 14.2 as soon as any richer-mixture acceleration ends.

 

--On the right hand side of the chart, you can see the effect of fuel-cutoff, AFR goes to 22 (full scale). It really does shut of the fuel! However, it gets back to the 14.2 range pretty quickly once it exits fuel-cutoff mode.

 

14.2afrlclog.jpg

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Still digesting all this great data but wanted to point out there is no easy or definitive way I can think of for the Techlusion to know when the Motronic is closed-loop. Remotely possible for very smart algorithms. Unless you believe in fairies.

 

Pretty simple for the Techlusion to scale-up the O2 output before it gets to the ECU - either a fixed amount or proportionally. Piece of cake for an op-amp (of which a couple have to be inside the Techclusion).

 

Ben

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Honestly, I can't figure out exactly how it works, and I would think for sake of intellectual property, they would like us to keep guessing! I know that it does what it says. Thinking about it though, I think it uses the signal from the 02 sensor simply to detect when the motronic goes into closed loop mode. You can see this on the 1332 module I have. (A blue LED flashes on the display when closed loop is engaged )- At this point, it then adds more fuel simply by extending the injection period. So it simply watches the 02 sensor for its engagement into closed loop. The ECM would ground out that circuit anyway, to close the connection. Remember as well that the injectors are essentially spliced into as well. The techlusion assumes control of injection.

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Roger, You can see how it does a remarkable job of keeping the mixture close to, or at 14.2 Very nice data.

Edited by steelerider
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Thanks, it took some effort and I needed a lot of input from others to be sure it would work and not be bad for the bike.

 

Cost wise, it is among the least expensive things you can do to richen the fuel: an LC-1 with gauge and wideband O2 sensor is $169.99 no shipping no tax at Amazon.

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I've got some cleaned up pictures of the LC-1 Install which I will post soon. Before finalizing the install, I needed to know whether the Motronic MA 2.4 would throw an error code and/or disable Closed Loop operation if it didn't see an O2 Sensor heater.

 

In many ECUs, the monitor O2 sensor heater current to determine if the sensor is present and if it is working. Since there is no documenation, the only thing to do was cut the O2 heater wires and see what happened. I rode for an hour with the heater disconnected.

 

The bottom line is, that the Motronic MA 2.4 does not produce any error codes if the heater is missing, and still runs its Closed Loop program.

 

This was good news for the final installation since it meant that I didn't need to find a place to mount a 10 ohm resistor dumping nearly 20 watts of heat.

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  • 2 weeks later...

Below is a chart of a startup sequence and drive off. You can see the richness starting on the left, moving to closed loop at 14.2:1 AFR on the right. In between are some lean splikes from deceleration enleanment and from fuel overrun cuttoff (biggest splikes). You can also see a restart just right of center where it goes quickly through a rich sequence (idle lever not up). You can also see some rich blips as I roll the throttle on.

 

startafr.jpg

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Here is a plot of AFR for my '04 R1150RT cold started with the throttle and cold start levers in three positions. Ambient temperature was 35 F.

 

1) For the left hand third of the plot, the cold start lever is on, the engine is idling smoothly and the AFR is in the 12s. Notice that the mixture is appearing to get slightly richer in the first 40 seconds. This is because the fuel is being atomized and burned better, leaving less oxygen in the exhaust. Less O2 is interpreted by a wideband oxygen sensor as a richer mixture.

 

2) In the center part of the chart, the cold start lever is abruptly switched off. At first the mixture seems rich due to less air going in. But after a few cycles, with less air going through the TBs and the engine still cold, the rich mixture isn't atomized as well, the engine misfires, and the O2 sensor reads the un-consumed oxygen as a leaner mixture. I will say that a different way: there was enough fuel but not enough air and all the fuel didn't burn, leaving unburned O2 in the exhaust which was read by the sensor as leaner.

 

3) Cold start lever still off but throttle cracked open for smooth idle. Better combustion so the AFRs return to the 12s as the fuel and oxygen burn more completely.

 

Bottom line: cold engines need more fuel AND a bit more air to idle well. The oil temp sensor reading tells the motronic to add fuel, the rider uses the cold start lever to add air.

 

threeidles.jpg

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Still digesting this wonderful real data.

 

Roger, please excuse me if I mention something you know perfectly well, but the "cold start" gizmo is nothing but a long string that tugs on the butterflies shaft (metaphorically speaking) - and hence the TPS, of course.

 

It isn't doing anything different than stepping on the throttle would do.

 

The state of the engine is different and so the two temp trims are a bit off - but the trims are pretty minor unless you live in Canada, of course, and only the engine oil temp is changing during the course of your data run - unless you are heading up a mountain.

 

Ben

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Still digesting this wonderful real data.

 

Roger, please excuse me if I mention something you know perfectly well, but the "cold start" gizmo is nothing but a long string that tugs on the butterflies shaft (metaphorically speaking) - and hence the TPS, of course.

 

It isn't doing anything different than stepping on the throttle would do.

 

The state of the engine is different and so the two temp trims are a bit off - but the trims are pretty minor unless you live in Canada, of course, and only the engine oil temp is changing during the course of your data run - unless you are heading up a mountain.

 

Ben

 

The idea for taking this data came from a question in another forum. Someone thought the TPS on some bikes was driven directly by the cold start lever (it's not) and whether the mixture was richer if you used the cold start lever versus the throttle (mixture is the same).

 

Since the LC-1 gives you programmable Lambda AND realtime AFR data I decided to look at what happened under the three circumstances. Beyond the fact that it is the Oil Temp sensor that determines Warm-Up Enrichment which most know, it was interesting for me to see:

 

1) Just after start, the mixture seems like it's getting slightly richer, it's not. What is happening is the combustion gets better over the first 30-40 seconds, consuming a bit more of the oxygen (which is what an O2 sensor measures).

 

2) If you try to idle a cold (Canada cold) engine with a rich mixture but not enough airflow (middle of graph) a rich mixture will misfire--and look lean! That's due to unconsummed O2 (and unburied fuel) reaching the O2 sensor. Here is a good example of a rich mixture, with oxygen still in the exhaust that would start burning in a hot catalytic converter. Misfiring can be very damaging to cats.

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  • 2 weeks later...
roger 04 rt

Now that I can program my Closed Loop AFR where I want, I've started to think about the "best" place. I've been running between 13.8 and 14.2:1. I've also been thinking about why such a small mixture shift, only several percent, makes such a big difference to performance and smoothness. Yesterday I came across an article on EGT, CHT, AFR and mixtures that answered many of my questions. Here is a link to that three part aviation article: Understanding Best Power/Economy -- Back to the Future . The article also explains how you might get a "lean" mixture to run smoothly. (Chart from the article below.)

 

Some key points from the article:

-- In the engines they have studied, cylinder to cylinder AFR variation can reach 8-12%. So at the extreme, one cylinder could be as rich as 13.8:1 and the other as lean as 15.6:1 at the same moment.

 

-- Rich of Peak EGT (richer than about 14.7:1) operation is much less sensitive to AFR variation due to the depletion of oxygen by combustion. In other words, once the oxygen in the cylinder is used up, a little more or less fuel doesn't effect the horsepower of the cylinder/engine.

 

-- When operating Lean of Peak (leaner than 14.7:1), difference in fueling leads directly to differences in cylinder/engine power. There is still oxygen available, adding a little fuel adds a bit of power.

 

-- Roughness in leaned engines is usually due to cylinder to cylinder power imbalances, not lean misfiring.

 

-- Motors with very well balanced air intakes and fuel injectors can be run Lean of Peak more effectively.

 

-- Considering cylinder head temperature, 14.7:1 is the hottest AFR.

 

Some thoughts after reading the article:

 

-- A shift of AFR to 13.8:1, will add several percent to BHP in the cruising range, but not at high powers where the Motronic already runs richer mixtures. (N.B. CO pot R1100s are specified to idle between 13.8 and 14.1, so I guess the engine is okay operating there.)

 

-- After balancing airflow at idle, for motorcycles using a stock narrowband O2 sensor, it might be better to adjust the right cylinder throttle plate for smoothness (equal HP) at 3000-4000 RPM, rather than exactly equal manifold pressure. How could that be done?

 

-- There is value in having a very well matched set of injectors. What is the best shop for getting these?

 

-- For a stock setup, Open Loop operation will be smoother than Closed Loop since the fueling isn't varied. Adding a BoosterPlug will add power and smoothness when the O2 sensor is disconnected by getting closer to a best power mixture, also adding some insurance against leanness caused by E10 fuel.

 

-- My LC-1 Wideband O2 sensor will smooth out Closed Loop operation with a shift to 4-6% percent richer than 14.7:1. Example below.

 

When the R1100/1150 engine goes into closed loop operation, the fueling is ramped a few percent below 14.7:1 and a few percent above. Given the above points,  I can imagine a case as follows:

 

A) Cylinder left is 5% leaner than Cylinder right

B) Motronic Closed Loop AFR range: +/- 2.5% (est.)

C) Therefore in Closed Loop the left cylinder runs between 14 and 14.7, while the right cylinder runs between 14.7 and 15.4.

 

Although this is hypothetical, and you could imagine better and worse scenarios, in this case the left cylinder is always Rich of Peak, its power doesn't vary much during the Motronic's Closed Loop operation. But the right cylinder in my example is always Lean of Peak, so as the Motronic ramps fueling up and down, the power in the right cylinder varies. (Sounds like surging.) Even with these imbalances, a shift of 5% to 14:1 Closed Loop AFR will keep Closed Loop operation rich of peak for both cylinders at all times.

 

Here are some interesting charts from the article:

pt2fig2.jpg

pt1fig2.jpg

 

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-- After balancing airflow at idle, for motorcycles using a stock narrowband O2 sensor, it might be better to adjust the right cylinder throttle plate for smoothness (equal HP) at 3000-4000 RPM, rather than exactly equal manifold pressure. How could that be done?

 

 

Afternoon Roger

 

Thanks for the follow up info.

 

As I have posted here a few times in the past-- balancing for matched or even "engine vacuum" is not the best way on the BMW 2 cylinder boxer.

 

That method is basically used as it is easy, quick, gets it close, & can be done by a method that can be seen & measured by an instrument. Balancing for even POWER is the best way as far as I'm concerned.

 

Personally on my own BMW's I have used the even-power side to side method for a long time now.

 

Due to a few people on this site that like to question this method & don't seem to understand it's possibility I will respond to you on a PM so as not to turn this thread into a hijacking.

 

 

 

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Peter Parts

About tuning for equal power from the two cylinders (indeed a great idea), I am "a few people on this site that like to question this method & don't seem to understand it's possibility". OK, maybe DR doesn't mean me since I DO think this is a great idea but I have no idea how DR does it.

 

I have asked DR to explain his method many times and I can not recall ever seeing a description or even a hint about how he does it. If DR will please provide a link to where he explains the method he has advocated a number of times on this forum, many of us will be very grateful for the education, me more than anybody.

 

Roger -

 

Although I know a guy who will object bitterly for me to so much as mention a BMW shortcoming, but BMW is especially nasty in having rather loose injector balance requirements. If I recall, it is Adam Wade who says within a broad 10% tolerance. Even a TwinMax can read within that kind of tolerance, let alone BMW who can match injectors that arrive in a big mixed box to 2%, if they wanted to. This is unforgivable for the manufacturer of boxer engines.

 

BUT... as I discuss in my write-up, when you take your injectors to the cleaner-person (which everybody should do every three years), they will give you before and after flow stats, unless you are not using a qualified shop.

 

Some smart folks order matched pairs from RJ or some initials like that - the gold-standard of injector companies. Not expensive.

 

Ben

Edited by Peter Parts
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roger 04 rt

I plan to send my injectors out this spring out of curiosity. I'll post the report when I get it.

 

Ben, have you sent yours out? How were they?

 

A rule of thumb from the curves: at lambda <1 adjust air to balance power; at lambda>1 adjust fuel to balance power. So how do you adjust fuel imbalance? Maybe match them and add a voltage regulator to one of the power supplies!

Edited by roger 04 rt
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Peter Parts
I plan to send my injectors out this spring out of curiosity. I'll post the report when I get it.

 

Ben, have you sent yours out? How were they?

 

A rule of thumb from the curves: at lambda <1 adjust air to balance power; at lambda>1 adjust fuel to balance power. So how do you adjust fuel imbalance? Maybe match them and add a voltage regulator to one of the power supplies!

 

Roger -

 

My write-up has lots of details about cleaning. Mine went to the cleaners around 25,000 miles on the best gas, if I recall. Not too old, eh. But still needed attention.

 

Hey, I wonder how many riders out there are complaining about surging when their problem is dirty injectors cutting the fuel supply? The injectors are VERY sensitive to collecting dirt.

 

"Balance" has two parameters: rate of flow (the cleaning did increase the flow rate of both injectors by a small amount; mine were off balance two percent when dirty and same imbalance after cleaning) and a judgment of quality of spray pattern (slightly impaired when dirty, less when clean). I don't believe 2% is much of an imbalance but then yours could be less or more.

 

I couldn't detect a difference I'd confidently attribute to the cleaning, as I recall. But then these "tests" are terrible experiments because you are screwing around with a bunch of things at the same time and maybe my injectors were OK to start with.

 

But I think the RC (Russ Collins) matched injectors are the way to go.

 

I don't think there are feasible ways to re-shape the injector pulses. These are strong pulses and the "pintle" valves are pretty much all or nothing and not variable in any electronically simple way.

 

Frankly, I was astonished to learn BMW uses a wasted spritz (analogous to the "wasted spark" design), flushing both injectors even at the perfectly wrong moment for one of them. Very dim, wasteful, silly, and not much trouble to create an ECU that had two power transistors to trigger the injectors separately. I can't wait for what-his-name to tell me BMW engineers always pursue the True and Pure.

 

Roger - if DR PMs you his method for balancing the jugs based on power output as he promised, please ask him if he gives his approval for you sending it to me too.

 

Ben

Edited by Peter Parts
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