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2004 R1150RT Wideband O2 Sensors

Roger, I really appreciate your generosity in sharing your data on the forum. It sheds a lot of light on an area about which there is much conflicting information. Your data and explanations are clear enough that even a non-technical person like me can follow along, and understand and evaluate for myself what you are doing and what the results are. Very nice!

I've been trying out some of your ideas on my own 2001 R1150GS. First, I found the bike performed better (more power, no evidence of surge) during the first couple of minutes after a cold start when the Motronic is running a more enriched mixture and before it goes to Closed Loop. Then, as you suggested, I disconnected the O2 so the motor would run Open Loop all the time and installed the Booster Plug (thanks for the loan) to enrichen the Open Loop tables in the Motronic. The bike ran beautifully! The surging was gone, throttle roll-on and roll-off were smoother, and the bike ran stronger in the mid-range. (I ran all of these tests with the Cat Code Plug in.)

Yesterday when I was out I decided to do a comparison just to refresh my memory -- I removed the BP, left the O2 disconnected, and reset the Motronic. The surge returned and as near as I could tell the mid-range wasn't as strong, and the throttle on/off was more abrupt. If I'm understanding this correctly, the bike was back at the 14.7 AFR programmed into the Motronic Open Loop tables, confirming that the engine runs better with a richer mixture as provided by the Booster Plug when running Open Loop. I couldn't really tell any difference between Open Loop without Booster Plug, and stock Closed Loop configuration.

If I'm understanding your latest post correctly, it just might be possible that if/when I install an LC-1 on my bike the Motronic might be able adapt the Open Loop tables to function at the same target AFR as the wideband O2 is set at and, if so, could save me the cost of a BP. I'm looking forward to seeing more of your test data with the LC-1 without the Booster Plug to see if you can get the same level of performance as running Open Loop with the Booster Plug. If so, it seems I would have two options -- disconnect O2 and install Booster Plug, or install LC-1.

Keep up the great work, Roger.

Thanks for your comments, I'm glad that you got a good result. Several people have borrowed the BP now for 1150s running Open Loop and gotten similar results.

And yes, I think you have either option. Open Loop and BoosterPlug being the simplest and getting the AFR to 13.8 to 14.2 depending on fuel and bike tolerances; LC-1 retaining full Closed Loop operation and programming flexibility for a specific AFR target.

When I have some more time, I'm going to run a version of the charts below for Open Loop w/Reset Motronic and Open Loop w/Reset Motronic and BoosterPlug so that there is another baseline for all of this.

afrresetadapt1.jpg
 
Yesterday afternoon I disconnected the Wideband O2 sensor so that I could measure the "raw" or Open Loop, Air Fuel Ratio (AFR) of the Motronic MA 2.4., with Pink Coding Plug. And then measure the Open Loop effect of the BoosterPlug. The motorcycle is running 93 Octane E10 fuel, which is important since it has shifted the curves upward by about 4%, meaning running 4% leaner.

In all the charts, there are two marker lines, one is at 14.7:1 (normal Closed Loop stoichiometric) and 13.8:1 (my richer Closed Loop target that creates more power). In the first photo there are two charts: the top chart is Open Loop, the lower Open Loop plus BoosterPlug.

The top chart below shows Open Loop AFR, after the Motronic is reset, and from a Cold start. For the first three minutes, you can see the AFR moving from 13:1 to the low 15s as the bike oil warms up. If I were running pure gas, the warmup would be in the 14.7 range, but E10 leans out the mixture. Much of the cruising time, the AFR is between 15:1 and 16.5:1--fairly lean. Notice in the histogram inset chart that the bulk of AFRs are between 14:1 and 16:1, even including acceleration.

The in the lower chart, the bike is warm, the Motronic is still reset but a BoosterPlug has been connected, dropping the air inlet temperature (AIT) signal to the Motronic by 20C. There is a similarly large spread of AFRs, but now they run between 13:1 and 15:1, about 6-7% richer. I was surprised at how much the AFR varies in Open Loop operation.

afropenbp.jpg


For comparison, look at the next photo, the conditions are reset Motronic, no BoosterPlug and Closed Loop at 13.8:1. The upper run is the first test run after reset and the lower run is the second run after reset. Since the Motronic is only Closed Loop about half the time in these charts, and comparing these two runs to the first photo (Open Loop conditions), you see Adaptation, the learning of Closed Loop applied to Open Loop conditions, and in the second run looking at the even tighter spread of AFRs, further Adaptation.

afrresetadapt1.jpg


Some conclusions:

1) E10 fuel results in leaner Open Loop operation
2) Open Loop fueling results in a wide variation of AFRs
3) The BoosterPlug does enrichen the fueling tables by 6-7%, but only in Open Loop operation. Connecting the O2 sensor starts the process of Mixture Adaptation that negates the effect of air temp shifting.
4) Closed Loop operation tightens the fueling range
5) Closed Loop operation allows the Motronic to correct for E10, aging injectors and air filters, and variations in battery voltage and fuel pressure.
6) The Motronic is a learning, adapting engine controller that takes what it measures in Closed Loop operation and applies it to adjust Open Loop fueling. (The mechanisms and degree could be examined further.)
 
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roger 04 rt said:
Today I had the chance to answer a question that's been on my mind, how would my 04 RT run if I programmed lambda from 0.94 where the Wideband O2 has been (13.8) to a leaner than stock setting of lambda=1.06 (15.6:1)? The answer: Not Terrible.

After programming the LC-1 to the leaner setting, and then resetting the Motronic and removing the BoosterPlug, I ran a 10 mile test loop. At first, during the warm-up phase with enrichment by the Motronic and Open Loop, it seemed fine. But as I passed through 4 bars on the temperature gauge, it was apparent that the motorcycle was noticeably less responsive to the throttle. Then, fully warmed up, I started a climb through the gears, guess what? The motocycle surged around 3000 RPM in second, third and fourth gears--not a pronounced surging, just subtle modulation of the torque and shifting note at the exhaust. I couldn't wait to get back and reset to lambda=0.94.

So what did I learn? There is definitely an AFR component to the Boxer surging phenomenon: 6% leaner than stock is too lean for sure, and I know that 6% richer is great. Where is the spot in between the two ends that is just rich enough? Just a guess, somewhere between 14.0 and 14.4.

After making this test run at 15.6:1, I turned off the motorcycle, quickly reprogrammed the LC-1 to 13.8:1 which is an instantaneous change for it. I also reconnected the BoosterPlug. Then I quickly reset the Motronic, twisted the throttle twice and restarted.

The motorcycle immediately went into Closed Loop mode (see the chart photo below, top line is 15.6:1 lower line is 13.8:1) but was running still at 15.6:1 ! Apparantly I was too quick with Fuse 5 and the Motronic didn't reset. It still had its adaptation values for closed loop idle at 15.6.

After about 10 seconds after start, it caught on that the mixture was too rich and by about 15 seconds after start had locked to the 13.8:1. This is the clearest example of Closed Loop Adaptation Values that I have spotted. (And it seems it takes more that 20 sec. to reset the Motronic--or I only think I reset it and forgot.)

I programmed it to 13.8:1 but it ran for short time at 15.6:1, it had to have remembered it from a few minutes earlier!


afr15.6.13.8.jpg
 
GS-911 as Intertia Dynomometer

The GS-911 time stamps, to the millisecond, all the data it collects. Somewhere along the line it hit me that it could be used as a Inertia Dynomometer since it collects RPM data and the transmission ratios are printed in the R1150 BMW Repair Manual.

I've also been curious about the 1150 Torque at 2000 RPM at a 13.8:1 mixture. The final piece of the puzzle was using some of the HP physics that I boned-up on for the R1150 Gas Mileage thread.

A couple key (rough) numbers:

--8 to 12 ft/sec-squared is a decent rate of acceleration for town and highway driving.

--R1150RT and rider (in my case) weigh about 800 lbs.

--It takes 25 to 30 horsepower to accelerate bike and rider at 8-12 ft/sec2 plus 2-10 horsepower for aerodynamic drag between 30 and 60 MPH

--25 Horsepower corresponds to 65 ft-lbs of torque required at 2000 RPM. But 40 HP translates to only 52 ft-lbs. at 4000 RPM.

Have a look at the chart and data below which were taken in 4th and 5th gear, starting at 1500 RPM and 2000 RPM respectively and with Wide Open Throttle. It looks like (and felt like) there was just enough torque to meet the HP/Torque/Acceleration targets above at about 2000 RPM in 4th gear and about 2500 RPM in 5th.

There's lots to discover but, for instance, look at the 81 degree TPS angle and the 60-70 ft-lbs of torque. Notice too, the relatively flat rate of acceleration from 2000/2500 to 4000 RPM. It's making more HP as it accelerates but air-related drag is increasing too.

The graphs are choppy because I didn't use a high enough sampling rate and drop off at 4000 RPM or so because that's where I let go of the throttle on the in-town road where I was trying this out.

lowtorque.jpg
 
Now that I have about 2000 miles on my '04 1150RT, wanted to see how things have settled in. It has been a couple of months since I last reset the Motronic and cleared any Adaptation Values that might have been "learned" by the Motronic. So I made a couple checks.

First I measured the warm-up transition from start to running closed loop. As mentioned, I haven't reset my Motronic for over a month and have taken many, varied rides. I wanted to see how things looked and whether there was clearly ADAPTATION going on. The results are that the Motronic has "learned" about the BoosterPlug, E10 fuel I run and Wideband O2 set at 13.8:1.

The result that can be seen from the chart below is that everything has been shifted to the desired afr of 13.8:1, including the cranking and warm up period. Booster, E10 fuel and LC-1 are operating in harmony with each other.

Below is the warm-up from a cold (85F is cold today) to hot (Closed Loop) motor. You can see the cranking and afterstart enrichment on the left at about 12-12.5:1, the initial warmup at 13.1:1 (about 5% below 13.8), final warmup enrichment at 13.3:1 (3%) for a few seconds and then smoothly transitioning into closed loop for the right hand half of the chart. The Closed Loop AFR spread is a mere 2.5% because of the speed of the LC-1. Gas mileage from for the most recent tank of fuel running premium E10 was 44 mpg (235 miles and 5.3 gallons).

The lines on the chart are blue 13.8:1 and red 13.3:1.
adaptsurprise.jpg


Here is an Autolite Plug with 2,000 miles of mostly local driving at 13.8.
13.8autolite.JPG
 
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Hi Roger,
You know that on the twin spark 1150 you can't really tell much by looking at plug color as an indicator of proper A/F ratio. That's because the secondary plugs will ignite the mixture with or without help from the primary plugs. I lost both stick coils and rode home on the secondaries a couple hundred miles and the primary plugs looked about like your pix.

Oh, Earle has ordered his parts and is awaiting arrival. I hope he needs more help as it would be a nice ride on the Idaho back roads with wife on board as she didn't make the last trip with me. I just love that part of the world.:)
 
Great data, but over whelming unless you have a good understanding of fuel systems, and fuel injection in particular.

My 94 RS never had a surging issue. I believe the real early Oilheads basically ran in open loop mode all the time. My 94 RS has no CAT code plug, but I have read there is simply a jumper wire in the harness where the code plug connections would normally be.

Beyond that, the only things I have done to my RS are:
1. Installed the GS intake tubes, which I later shortened by about 1.5" to reduce the intake "honk" on acceleration.
2. I built my own free-flow baffling for the stock muffler/canister, but I still have the stock cat-convertor.
3. K&N intake filter.
4. Techlusion system for the fuel, as my bike popped excessively on decel (with the clutch out) after I modded the muffler. The Techlusion I adjusted barely off the minimum settings to reduce the popping.

With this, the Autolite 3923 plugs come out a nice tan color, and I get about 43 to 45 mpg fuel mileage, even two up.
 
Hi Roger,
You know that on the twin spark 1150 you can't really tell much by looking at plug color as an indicator of proper A/F ratio. That's because the secondary plugs will ignite the mixture with or without help from the primary plugs. I lost both stick coils and rode home on the secondaries a couple hundred miles and the primary plugs looked about like your pix.

Oh, Earle has ordered his parts and is awaiting arrival. I hope he needs more help as it would be a nice ride on the Idaho back roads with wife on board as she didn't make the last trip with me. I just love that part of the world.:)

It'll be interesting to hear how Earle makes out once he gets the parts. He's got a great bike there.

I agree with you about the plugs, you do lose some power with only one set of the plugs running but I've never thought about how they'd look. In a piston powered aircraft, during runup, you test both mags and sets of plugs before take-off. But back to the point: I'd been curious about how the plugs looked (and they're all firing) after a few thousand miles running 6% rich. The bottom line is they look pretty normal.

Great data, but over whelming unless you have a good understanding of fuel systems, and fuel injection in particular.

My 94 RS never had a surging issue. I believe the real early Oilheads basically ran in open loop mode all the time. My 94 RS has no CAT code plug, but I have read there is simply a jumper wire in the harness where the code plug connections would normally be.

Beyond that, the only things I have done to my RS are:
1. Installed the GS intake tubes, which I later shortened by about 1.5" to reduce the intake "honk" on acceleration.
2. I built my own free-flow baffling for the stock muffler/canister, but I still have the stock cat-convertor.
3. K&N intake filter.
4. Techlusion system for the fuel, as my bike popped excessively on decel (with the clutch out) after I modded the muffler. The Techlusion I adjusted barely off the minimum settings to reduce the popping.

With this, the Autolite 3923 plugs come out a nice tan color, and I get about 43 to 45 mpg fuel mileage, even two up.

Hi AndyVH, Yup, according to the drawings, you've got a jumper in the harness. Red100RT confirmed it on his bike, an RSL of that vintage. Interestingly if you bought it without a catalytic converter they put a socket in for a plug so that you could add a Cat later. !

You're very right about all the data in this thread, it is overwhelming. And that's my fault, I keep thinking of things to measure. That last chart shows that the Motronic is completely comfortable with an O2 sensor that switches at another air to fuel ratio. The curve looks just like a stock curve would look if you added 6% fuel across the board.

I've included all the data I've taken as I went along because there are so many aftermarket fixes--chips, intakes, exhausts, add-ons--that make great promises but include no description of how they work and no proof that anything has changed.

Anyone who's ever turned the needle jet adjustment on a snowblower, weed-whacker, go-kart, chainsaw or airplane knows that there's a setting where the machine just "hums". They run over a wide range of adjustments, but there's that magic point where they're smooth, with lots of power, and happy. My "needle jet" is now the LC-1 and I turn the screw with my PC.

As I come to the end of this project I have a lot of respect for the power of the Motronic MA 2.4. It has a good set of sensors, quickly adapts to lots of changing variables. Some of the things learned along the way:

1. The Motronic MA 2.4 will run very happily at an AFR setpoint other than the stock sensor's 14.7:1. The LC-1 doesn't interfere in any way with the Motronic operation.

2. The sole downside is that there should be an increase in CO and unburned Hydrocarbons in the exhaust to the levels of a European R1100 with CO pot. I take a small comfort knowing that as these bikes approach 10-20 years old, their emission systems are unlikely to be in tip-top shape anyway. And relative to the dozens of other changes owners are making with intakes, exhausts Techlusions, Powercommanders, etc. this mod isn't out of line. I have kept the Evap Canister.

3. The Motronic runs compatibly with the LC-1. I've tried hard to find things wrong and can't. No error codes, no lost functions.

4. The Oilhead engine is smoother and has better low-end performance with just a few percent more fuel than stock. Very impressive pull in 5th and 6th gear from 2500 rpm on up.

5. Gas mileage seems about the same as with the stock sensor. I attribute this to being able to often run in a lower gear (due to the increased low-end torque) at a place where the Oilhead engine is more efficient ( better specific fuel consumption).

6. Other than replacing the stock O2 sensor with a wideband version, everything else on the bike is stock. Unlike a Techlusion, you know exactly what an LC-1 is doing to the mixture. Unlike a PowerCommander III, no dyno tuning time was required to implement this and measure its effects.

RB
 
After my recent Fuel System Failure, I decided to further richen the mixture of my R1150RT from 13.8 (where it had been for several months) to 13.5. 13.8 was good and a bit smoother after the injector cleaning but I wanted to see what 13.5 was like.

I didn't make any quantitative measurements yet but it seems that the engine is smoother and has even a bit more pull than at 13.8.

I don't think I'll go much further than 13.5 because the warm-up fueling has gotten richer through adaptation, but I am testing some other ideas.

Most of the time I've been using a BoosterPlug that I already owned to pre-offset the fuel table to be 6% richer. This meant that the Motronic had to do less work to adapt from its basic setting at 14.7 (which is more like 15.4 on E10), to get to 13.8 and now 13.5.

This weekend, I disconnected the BP, left the LC-1 at 13.5, and reset the Motronic. Then took a couple long rides at various RPMs and loads to help the Motronic re-learn the corrections. Some quick measurements show that it has Adapted. When I have a chance I'll publish a graph or two.

The other thing I'm thinking about is changing my fuel injectors. After having them cleaned and tested. I have the Bosch P/N and believe that these are 325cc per minute injectors. I'm going to try and find some exact replacements that are 360cc. That would be 10% more fuel, 4% for ethanol and 6% for 13.8. The idea is that the Motronic would have to do much less work to rebuild the adaptations after a reset.

Anyone have any thoughts on this bigger injector idea?
 
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Here is a graph that I plotted a few days ago after fully reseting my Motronic, settting the LC-1 to 13.5. It took several rides at many RPMs, gears and TPS positions to relearn the Adaptation Values. Here's the plot, made after a warm restart, meaning that the bike was at temperature and was back in Closed Loop quickly.

fullyadapted13.5.jpg


What you can see is that for the first 12 seconds (until the 2:27 mark) the bike is Open Loop. In that period there is the After Start Enrichment and Warm-up Enrichment--the up-slope that levels at 13.2. Then at 2:27 it snaps into Closed Loop at 13.5.

What is noteworthy about this plot is that the entire curve has been shifted down by 12% or said another way, the Motronic has added 12% more fuel to both Open Loop and Closed Loop--4% more fuel because I run E10 and 8% more because the LC-1 is programmed to 13.5:1.

If the Closed Loop learning had not been applied to Open Loop (and you can see where Open Loop starts after a Motronic reset in plots from earlier in this long thread, here), The Open Loop phase would have started about 8% higher at 13:1 and the pre-closed-loop plateau would be at about 14.3:1, then it would have snapped down to 13.5 for the Closed Loop phase.

For me, this pretty fully settles the question of Adaptation and whether the Motronic MA 2.4 has that ability or not. Sometime when I get a chance I'll also measure the WOT AFR to confirm Adaptation there as well, but as an Anti-Knock measure, it's just as important to have Adapted there so I don't expect any surprises.

RB
 
In the prior post I showed that the Motronic had Adapted Open Loop fueling, without a BoosterPlug or any other modifications, to the 13.5:1 AFR that the LC-1 Wideband O2 replacement is set to.

Because the move from 14.7 plus the leanness of E10 requires the Motronic to add 14% to the stock fuel tables to reach 13.5, and because adaptation is deliberately a slow process, it took several rides over several hours for the Motronic to dial itself in.

Next I wanted to see how quickly it would Adapt if I shifted the IAT sensor by 30C, an 11% increase in fueling, such that the Motronic only had to move the last 3% (14% - 11%).

I bought a few EV1 connectors and wired them in series so that the BoosterPlug output had the stock IAT added to it. I then checked with the GS-911, the series pair did shift them temperature -30C. Next the Motronic was reset and I went out for a test ride. (LC-1 still set to 13.5.)

The result was that the bike needed little adaptation to get Open and Closed Loop fueling in sync. This produced the smoothest engine performance in all the testing I've done, and kept the point at which I've got strong roll-on throttle at about 2600 rpm.

My next test will be to remove the BoosterPlug, run with only the stock IAT and boost the fuel pressure to 50-55 psi using an external fuel pressure regulator from Aeromotive, installed in the return line to the tank. I will select and measure a pressure that boosts the fuelIng by about 12% and test ride to confirm similar results to the 30C temperature shift.
 
Fascinating. :lurk

Looking forward to further results/experiments, as I intend to heavily rely on this whole series when I turn to my '04 R1150RT-P this fall. :thumb
 
On Saturday I got around to boosting the fuel pressure to match my Wideband O2 setting of 13.8:1. I used an Aeromotive 13301 (picture below) and increased the fuel pressure from 43.5 psi (3 bar) stock to about 52 psi--install photos later. Although a BoosterPlug configured for -30C or just letting the Motronic "adapt" work, I wanted to input the actual air temperature and adaptation is a slow process.

Bottom line: My R1150RT is running its strongest and smoothest yet. The pull from about 2,000 RPM on up in 4th gear is strong. Fifth and Sixth gears are similar but a bit higher on the RPM. The bike is now stock except for the Wideband O2 and higher fuel pressure, and the Motronic has a direct connection to all sensors.

Here's why I have decided to boost the fuel pressure. BMW has done a good job designing the basic fuel map for the 1150 and I don't want to lose their design knowledge--they have a good map of RPM vs TPS (how much air is going into the engine), they just plugged in lean fuel values. Look at the fuel map for a Ducati that I linked from Brad the Bike boy's site. This is not the same map as an R1150RT but it can illustrate some points.

You can see that it has 16 RPM columns across the bottom and 16 throttle angles up the side. This table holds 256 values that specify how long, in thousandths of a second, to turn on the injectors for certain RPM and throttle positions--based on their detailed knowledge of how much air the engine draws at each point. These values are only valid for gasoline without ethanol, and for one air temperature, one barometric pressure and for 43.5 psi fuel pressure. The R1150 has sensors for actual air temperature, barometric pressure and battery voltage. Then it uses the O2 sensor in Closed Loop to determine the actual fuel pulse needed to correct for ageing and component tolerance and E10 fuel. It compares the actual pulse calculated by Closed Loop to the fuel table and comes up with a correction factor. BMW calls these correction factors: Adaptation values. From all the reading I've done there is probably no more than a 4 X 4 table of Adaptation values, maybe fewer. And these values change slowly. And while you're waiting for the slow change your bike doesn't run it's best.

The numbers in the table have been designed for a Closed Loop mixture of 14.7:1. When I fill up with E10 fuel, it would be better if every number in the table were 4% larger since ethanol is a leaner fuel than gasoline. Since I've moved the Closed Loop to 13.8, that means the numbers should all be 6% higher. So 6% for my AFR change and 4% for ethanol means I would like every number in the table to be 10% larger.

It's not really possible for us to go in and change the numbers in the table to make them 10% bigger. But you can boost fuel pressure by about 20%, and the injectors then squirt 10% more fuel using the stock map numbers. This means the fuel table now matches my wideband O2 setting of 13.8:1. And that means the Motronic doesn't have to work hard to Adapt the two to match.

The fuel pressure regulator has done away with the need for a BoosterPlug to richen the Fuel Map (The BP works by lowering the temperature the Motronic sees) and now I'm running without one.

As an example of Adaptation, I'll add some tables in the next post.

I've only had one day of running but the combination of wideband O2 and add-on fuel pressure regulator looks like a winner.



fuelmapexample.jpg



0539a811-d7bc-4780-a2aa-fdb1cb34cafd-800.jpg
 
I mentioned a couple posts ago that I would show where I've temporarily fit the Aeromotive 13301 Fuel Pressure Regulator (those of you who are more natural mechanics, try not to cringe at the tie-wraps). In the photo below you can see it in position below the right-hand throttle body intake-tube (where many have installed an external fuel filter).

The Aeromotive 13301 has four inputs (three of which are plugged) and a return. I've attached 18" lengths of fuel line hose with QDs on each end of the hose. This has allowed me to snap it in series with the return line from the R1150's fuel distributor, returning to the tank. The input of the 13301 is QDed to the fuel distributor and the output of the 13301 is QDed to the tank return line. The excess hose is looped around, staying clear of the moving parts of the throttle body.

The experiments have gone very well. The 52 psi setting adds almost 10% to every fuel pulse (that's 4% for E10 fuel and 6% for my Wideband O2 shift to 13.8:1). It does it reliably, allows me to remove the BoosterPlug so the Motronic knows the actual intake temperature and without waiting for the Motronic to go through a lengthy Adaptation Cycle (more in a coming post).

Because I have the Wideband O2 installed and can connect an AFR gauge at any time, I could confirm that 52 psi brought Open Loop fueling to about 13.8:1 on my motorcyle--an unexpected advantage of using the Innovate Motorsports LC-1. If I were to go leaner or richer with the Wideband O2, I will change the fuel pressure up or down as needed so that Adapation is nominally ZERO.

As for a final home I'm planning to get some proper clamps and make it look like the external fuel filter installation (or if I can find a spot under the tank, perhaps there. When I do that the hoses will be shortened and the extra pair of QDs will be removed in favor of Oetiker clamps.

Any suggestions on how or where to locate the 13301 would be welcomed.

fprinstalled.JPG
 
Am I understanding this correctly -- that increasing the fuel pressure takes the place of both the Booster Plug and Wideband O2 sensor/adjustment? Very interesting thread, Roger.
 
Am I understanding this correctly -- that increasing the fuel pressure takes the place of both the Booster Plug and Wideband O2 sensor/adjustment? Very interesting thread, Roger.
I've asked on Roger's BMWST thread a similar question -- I'm guessing the fuel pressure regulator still needs the LC-1/wideband O2 sensor to fool the engine computer into believing the 13.8:1 AR ratio is the 14.7:1 the computer is looking for.
 
Am I understanding this correctly -- that increasing the fuel pressure takes the place of both the Booster Plug and Wideband O2 sensor/adjustment? Very interesting thread, Roger.

The fuel pressure boost takes the place of a BoosterPlug in my implementation but the LC-1 is still needed too. You can boost the pressure and run open loop but you won't know what your mixture is. In a couple days I'll show a graph of why that is so.

Here's a longer explanation.

Before answering, and I'm sure you know this, I can only answer this question in the context of a stock motorcycle--stock intake, stock exhaust, stock Coding Plug, no other fuel injection changes. A bike should be well tuned, have good coils, good compression, good fuel hoses and pump and no defects.

With that proviso:

1) Closed Loop operation brings many benefits that have been discussed throughout the thread. The Motronic fuel tables are designed for an AFR of 14.7:1 but the Motronic algorithms are designed to converge around ANY transition point of the O2 sensor. The stock sensor transitions from 200 mV to 800 mV at an air-fuel ratio of 14.7:1. The LC-1 can be programmed to make that transition at ANY air-fuel ratio. Therefore to keep Closed Loop but move to another AFR you need something like the LC-1. A point I will make is that this is in no way "spoofing" the Motronic--it giving it a different switching point and working within it's design parameters.

A side benefit to the LC-1 is that you can always read your motorcycle's AFR. I have found this to be a very helpful diagnostic tool.

2. Since the stock fuel map is set for 14.7:1 at cruise, whether you shift the map using a fuel pressure regulator or an IAT shifting device is mostly a matter of choice. The closer your fuel table is to the O2 switch point, the smoother your engine runs while you wait for the Motronic to create its Adaptation Values.

Running the leaner E10 fuel, the Motronic has to adapt 10% to get from 14.7 (where it is starting) to 13.8. A BoosterPlug shifts things 6%, a fuel pressure regulator can shift things 10%.

Another example though would go like this, you're running gasoline with no Ethanol and moving from 14.7 to 14.1 (4% richer, it runs nicely there too). For this, you need only a 4% move.

3. Lastly, there is the Open Loop option. You lose the regulating benefits of Closed Loop. If you run gasoline, without ethanol, a BoosterPlug will get you about 6% richer, good enough for some.

If you run fuel with ethanol and add a BoosterPlug you only end up 2% richer than 14.7. I doubt you would notice the difference.

So running E10 and looking for a richer mixture Open Loop, I would go the fuel pressure route.

The problem with all the Open Loop options is that you have no way for sure to know what AFR you've ended up at. And like running a Techlusion, you have to use the "butt dyno". method.

My favorite for E10 Land:
LC-1 and Fuel Pressure boost to 52 psi

My favorite for Gasoline Land
LC-1 and a BoosterPlug because the BP is easier to install.

A compromise for E10 Land
LC-1 and BoosterPlug

This is probably a longer answer than you hoped for but there are several things to consider
.

RB
 
The computer and O2 sensor will sense and analyze the rich condition produced by the increased fuel pressure and lean the mixture. This will likely occur over tens of miles as the computer learns the new parameters of the engine. I considered increasing the size of my injectors to compliment the new header I'm going to mount. But decided against it, since the computer would adjust the pulse of the new injectors until it brought the A:F mixture back in line with the factory settings.

Currently running a Booster Plug and have for about 2 years, with good results.
 
The computer and O2 sensor will sense and analyze the rich condition produced by the increased fuel pressure and lean the mixture. This will likely occur over tens of miles as the computer learns the new parameters of the engine. I considered increasing the size of my injectors to compliment the new header I'm going to mount. But decided against it, since the computer would adjust the pulse of the new injectors until it brought the A:F mixture back in line with the factory settings.

Currently running a Booster Plug and have for about 2 years, with good results.

It won't revert. Let me explain.

By using a Wideband O2 sensor and programing it to 13.8:1 is what keeps the motronic from leaning the mixture back to 14.7:1. It is the combination of Lc-1 and fuel pressure that keeps it Closed Loop and richer.

If you look at the earlier charts you can see the the combo keeps conditions set as programmed indefinitely.
 
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