[Soliton]

The current situation:

• 1150 cc Horizontally opposed EFI -BMW motorcycle.

• The bike has ongoing electrical issues and the current proprietary EFI system is a "black box" It is fairly primitive by modern standards and has no capacity for re-flashing or re-programming to change values if mechanical changes are made to the engine.

• The intention is to fully re-wire the bike and in addition install an NO2C vC1 as a replacement for the Bosch Motronic system.

• A full conversion from Alpha-N to a speed density model is off the table. The extra work and costs are not a good return on investment.

• The current sensor setup is:

• • - 1 x TPS (only on the left hand side throttle body

• • - 1 x Hall effect sensor (tested and pumping out a beautifully strong trailing edge 5v square wave)

• • - 1 x Narrow band O₂ sensor. The current EFI switches between open and closed loop.

• • - 1 x Air temperature sensor

• • - 1 x Oil temp sensor.

Questions about the design:

• Will the NO2C in an Alpha-N mode benefit from using a broadband sensor or perhaps 2 (one for each cylinder). Welding in O₂ sensor ports is not a problem.

• • If yes, does the NO2C board support this or will I need some kind of plug-in module/s to do the job.

• A two cylinder horizontally opposed engine has 2 inlet manifolds. Is there any benefit to running MAP sensors?

• If yes:

• • Would I need one for each inlet (I can tap vacuum ports in the throttle bodies.)

• • • Does the NO2C have space for a second MAP sensor? Or

• • • Could I use a single sensor that is plumbed (via a cross-over tube) to the (newly tapped) vacuum ports.

A lot to ask but essentially Broadband O2 yes or no. MAP yes or no and if yes what config would work best. I don't want to find that what I have bought won't support what I designed or that I've bought stuff that isn't really necessary.

Thanks in advance,

Sol

[PSIG]

• 1150 cc Horizontally opposed EFI -BMW motorcycle.

• The intention is to fully re-wire the bike and in addition install an NO2C vC1 …

• A full conversion from Alpha-N to a speed density model is off the table. The extra work and costs are not a good return on investment.

Sounds like you are getting a handle on the planning. For my knowledge, why is SD off the table? The investment is simply connecting the on-board MAP sensor to the plenums, and blended AN (AN with MAP) can improve tuneability in certain areas of the tables. Just curious your perspective so we can help you better.

• Will the NO2C in an Alpha-N mode benefit from using a broadband sensor or perhaps 2 (one for each cylinder).

• • If yes, does the NO2C board support this or will I need some kind of plug-in module/s to do the job.

Yes, and yes. There are several options, so do some searching or see what your dealer has available. One WBO2 will do for EFI. Two for other data collection if you want it. Speeduino can log 2 but only uses 1 for operation.

This is likely your best MAP connection answer:

• • • Could I use a single sensor that is plumbed (via a cross-over tube) to the (newly tapped) vacuum ports.

[Soliton]

My reasoning for not going full speed density was simplicity and (I will admit it) lack of knowledge. I thought I needed to also have Mass Airflow Sensors installed as well. This would be a problem.

If I can just plumb in some vacuum ports and use a Y-piece to join both and run them into a single sensor that would be great. I thought of this as "Alpha-N +". I'm sure there is a proper term but until the whole business gave up the ghost 4 months ago the ECU from my perspective was just a box that did something. I did the mechanical stuff and it did the EFI stuff.

The exact thing I am thinking of is from DIY-EFI in the UK and they call it a "Compact 2 channel". The design incorporates the main Arduino chip onboard.
https://diy-efi.co.uk/product/c2c

I was planning to buy this, and a WBO₂ sensor. I'm tempted to start tapping the vac ports on my TBs. (I am aching to get the bike back on the road) but I will wait until I get all of the various bits of kit that I need.

[LPG2CV]

Before purchase, an ideal first step, is to determine the trigger wheel and sensor you have.

There are some BMW K series projects on the forum. If I recall, there you may find some info on their approach to the trigger wheel, or at least, the issues involved. Try an advance search on K100.

Edit

Note the K's used the L-Jetronic ecu

[PSIG]

You are simply missing some basic info to wrap your head around it. MAF has no involvement. Speed Density (SD) is using a MAP sensor and RPM to determine the air mass flow for calculating fuel. Alpha-N (AN) uses TPS for load and RPM to calculate fuel for estimated air mass, as a target of what it should be at that throttle and speed. Blended AN uses AN modified to include MAP, which is to help each type to be less confused at certain points.

This blended stuff is nothing new, and the factories today are moving from primarily MAF modified by MAP, back to primarily MAP modified by MAF. Use what works best for the application and how you use it. The factories have different goals than we do, so ignore what works for them and focus on yours.

[Soliton]

Thanks everybody,

I have a Speeduino C2C in my hot little hand. It is part of an end to end re-wire so it's gonna take a while but it will be worth it.

Thanks for all the advice, I appreciate it. I'm going to try to document it and post on some of the other BMW forums I subscribe to. The Motronic units have been a bane in BMW rider's lives for an age and I'm almost certain that if a simple functional alternative can be worked out that more than one or two will jump ship. I have already been pleasantly surprised at how much cheaper everything is. I bought a set of LS2 coils with built in igniters and they were half the price of the BMW equivalent.

Now comes the hard work!

[LPG2CV]

Will the C2C fit in the Motronic case? I've read a number of projects where an old OEM enclosure and connector have been re utilised in the project. I realise you are re wiring, but their purpose was to keep it looking orginal, and to be able to easily swap back.

[Marvin2Shoes]

Hi, I was wondering how this project has progressed as I have a R1200RT that is very ill and needs its ZFE and ECU surgically removed and relegated to a dumpster fire (where they deserved to be from new in my opinion).
I have the ability to fabricate TIG AC & DC and rewire bike from top to bottom but would like to chat with like minded people about the sensor issues with converting to Speeduino. Did you manage to use the stock camshaft/crank sensor or did one or both of these need changing? Your measurement of the 5V waveform suggested that at least one sensor was compatible. I searched BMW forums for your name and couldn't locate any further posts on the subject.

[LPGo]

Hi, I was wondering how this project has progressed as I have a R1200RT that is very ill and needs its ZFE and ECU surgically removed and relegated to a dumpster fire (where they deserved to be from new in my opinion).
I have the ability to fabricate TIG AC & DC and rewire bike from top to bottom but would like to chat with like minded people about the sensor issues with converting to Speeduino. Did you manage to use the stock camshaft/crank sensor or did one or both of these need changing? Your measurement of the 5V waveform suggested that at least one sensor was compatible. I searched BMW forums for your name and couldn't locate any further posts on the subject.

I have also a BMW1200 engine, but not in a motorcycle but in a car (Citroën 2cv). I developed a programmable ignition system with only 1 tooth at he crankshoft (45 degrees b.t.d.c.) it runs very well with 2 2cv carburators. I am now developing my own standalone board and when it is finished I will run the Bmw engine with it ignition and injection. take a look at my topic here viewtopic.php?t=5777

Take a look at my youtube channel www2cv4x4nl

My 2cv BMW 1200GS in action
https://youtu.be/cz538MeRvEM

Soon I will make my own topic with my BMW engined 2cv and my Standalone (Speeduino compatible) ecu.

[Marvin2Shoes]

So good to hear from you! I have been unable to find much technical information on the internet for bmw motorcycles... I am guessing that is a bmw policy given the inability to purchase a decent workshop manual for these bikes. I have checked your YouTube channel.
As you haven't yet tackled injection I am still unsure if stock injectors on camhead engines are compatible with the Speeduino or do I replace with injectors that work well with Speeduino? Also I couldn't really see which engine you are using, hexhead or camhead?
Did you use the original crank & cam sensors? I imagine when you tackle injection you'll be installing wideband Oxygen sensors in space of the stock narrow band ones?
I imagine the "stick" coils used are stock ones? Have there been any curve balls you've had to overcome while working on this project?