[MGR550]

Hello,
First project on the speeduino platform and its a weird one. 1975 Suzuki RE-5, 500cc single rotor wankel engine motorcycle. Peripheral port from factory, single plug (no "leading" or "trailing"), weird points style distributor/CDI box combination ignition setup.
Overall goal is just drivability and do what they wish they could have in 1975.

Hardware:
NO2C, to keep it compact
Fuel pump and reg TBD, got a combination incoming that I'm hoping will work
Throttle body, TPS, injector off a RMZ450 dirtbike, injector might be a bit small but can upgrade later. Also has a 3 wire MAP built in too.
LSU4.9 WBO2 and controller

Planning on gutting the 'distributor' points system and putting a trigger wheel w/ optical interrupt sensor in the housing
Will likely source an LS coil or similar

Software settings I'm bit less sure of and could use some input:
Usually you'd set a 13b as a 4 cyl to control leading, trailing, and sequential inj nicely, but this one only has a single rotor, single plug, so best to run it as a 500cc single cyl 2 stroke ( ie 1 injector and 1 spark per rotation)?
Is there a nice way to get the same plug to fire twice to mimic a leading and trailing without burning out the coil?

Any other tips or ideas on anything are more than welcome!

Thanks,
Matt

[LAV1000]

Hello,
First project on the speeduino platform and its a weird one. 1975 Suzuki RE-5, 500cc single rotor wankel engine motorcycle. Peripheral port from factory, single plug (no "leading" or "trailing"), weird points style distributor/CDI box combination ignition setup.
Overall goal is just drivability and do what they wish they could have in 1975.

Hardware:
NO2C, to keep it compact
Fuel pump and reg TBD, got a combination incoming that I'm hoping will work
Throttle body, TPS, injector off a RMZ450 dirtbike, injector might be a bit small but can upgrade later. Also has a 3 wire MAP built in too.
LSU4.9 WBO2 and controller

Planning on gutting the 'distributor' points system and putting a trigger wheel w/ optical interrupt sensor in the housing
Will likely source an LS coil or similar

Software settings I'm bit less sure of and could use some input:
Usually you'd set a 13b as a 4 cyl to control leading, trailing, and sequential inj nicely, but this one only has a single rotor, single plug, so best to run it as a 500cc single cyl 2 stroke ( ie 1 injector and 1 spark per rotation)?
Is there a nice way to get the same plug to fire twice to mimic a leading and trailing without burning out the coil?

Any other tips or ideas on anything are more than welcome!

Thanks,
Matt

Interesting project.
For opto sensor check the Optek OPB625, out of stock......
About the the leading and trailing spark from 1 one coil.
I don't think it wil work because coil needs some time to charge.

[MGR550]

I was hoping for the 'leading-trailing' spark thing to use it similar to a wasted spark system, where the residual charge in the coil (plus maybe a bit a small >/= 250 microsenconds charge between spark events) would be able to form a spark in the partially ionized burning gas which would be a bit lower resistance so might be viable. Anyways lol, minor details at this point in the build, just something neat to think about. Trying to make all my mods reversible incase I ever sell it to a collector or someone who cares about originality.

[PSIG]

IDI coils require a minimum dwell time to create a minimum energy field for effective spark. You can do timed trailing sparks with either two coil systems, each firing their own spark to their respective spark plugs, or a CDI-based multi-discharge system to a single spark plug. Multi-coil on one spark plug has been done, but those and their components (HV diodes) are rare.

Some tricky work has been done to fire only partial discharge (short spark time), retaining energy to re-fire after a quick dwell, but results are typically marginal, effectively two weak sparks. CDI can fire on IDI coils, but most systems are not crank-angle timed, and spark when they want to, not when you do. Can it be done? Sure. But I would wait until the project is stable and proven so the results of your multi-fire system can be seen clearly and assessed for benefit with metrics. That's me. Do your thing.

Final comment — if using IDI, choose your coils carefully for required dwell versus your firing cycle time. You need both dwell and firing times, plus a bit for switching, all squeezed into your calculated available cycle time. While there are exceptions to every rule, little CoP coils are typically high-current to achieve short dwell (probably not good on a low-amp bike system), CNP are lower current but typically longer dwell, and oddly enough distributor coils have shorter dwell to fire multiple times per-cycle. Note the trend of increasing size to get sufficient power with short dwell.

[CAnAm]

Interesting Project.
Will follow as I have an RE-5.
I'm going Speeduino for a 4G54 draw through carby setup to try and control timing at boost.
Will be a steep learning curve

[MGR550]

Quick update: Almost done the wiring finally, optical trigger works well on the bench with a 3d printed 36-1 wheel and will be making the exhaust pipe this weekend. I got a flange made for the intake manifold, but still need to actually make the manifold itself which will probably be the most difficult part of the whole build. The stock systems that I'm replacing are all so overly complicated to deal with the usual rotary quirks, will post pics of old vs new once all together.

Luckily the rx7 guys have lots of info on mapping for NA peripheral port engines so hopefully I can just scale down the fuel mapping and pretty much copy the ignition map minus a few degrees here and there to keep it safe. Plug location on the rotor housing is slightly different given the no leading and trailing vs the 13B so a static offset across the ignition map should correct for that.

some questions:
should I add flyback diodes on the fuel injector and fuel pump relay?
What is approx power draw of speeduino unit when running? I imagine inj+coil+computer+sensors wouldn't be more than 25W?

[LAV1000]

flyback diodes on injectors is not neccesary if you run "normal" high Z injectors.
For fuelpump relais, you kan buy them complete.

Power draw, I would be more concerned about the fuelpump....

[PSIG]

should I add flyback diodes on the fuel injector and fuel pump relay?
What is approx power draw of speeduino unit when running? I imagine inj+coil+computer+sensors wouldn't be more than 25W?

Agreed, typically you would not use a flyback diode on any injector, or other precision-controlled solenoid, as the diode will alter the operation time profile. Now for a qualified answer - you can adjust control to compensate for the changes a diode can cause, but that requires testing and control changes.

Relays normally contain their own flyback snubber (resistor or diode). Verify what yours has, and pay attention to control wiring polarity to avoid blowing any internal diode. Rule-of-thumb for Bosch-style diodes is (+) in on even-numbered terminals, and the load or control signal ground on odd-numbered terminals.

Yes, generally under 25W is typical power consumption for Speeduino, due to most power functions grounding circuits for control. However, if any functions are used or added that also consume power by delivering power to control (e.g., stepper IAC output), then add that to the total, and fuse accordingly, generally a 1A or 2A fuse. Ignition control output, biased temperature sensor, TPS power, etc, are assumed as part of normal consumption. WBO2 is typically powered on a separate supply circuit up to ±100W. See your device documentation.

[MGR550]

Ok thanks good stuff to know.
I'll have to measure power draw of everything when I put it all together, but controller @2A, pump @4A, WBO2 @ ~4A (SLCFree2), plus lights and other stuff should just be ok.

One last electrical question before I start plugging stuff in: what if any parts should share a common ground? or does it matter at all? ie if WB controller shares a 12V and GND with the main power in for the NO2C, will the output signal from the WB still be read ok? or same thing if the TPS gets voltage and gnd from the 5V power tap? Not sure if the ground is continuous through a regulator I guess is my question.. I'm more mechanical so learning the electrical as I go and I had a problem with this in a past project.

Also made a new 304 stainless exhaust this past weekend, should hold up to the heat well enough. The stock unit is a double walled set of pipes with air intake to cool the space in between the layers so were quite heavy and didn't allow for a WBO2 bung.
Thanks again all!

[PSIG]

One last electrical question before I start plugging stuff in: what if any parts should share a common ground? or does it matter at all?

Yes, it matters. Read-up on my links and comments here and here to get started.