- Mon Aug 23, 2021 5:07 am
#52677
Howdy all. Thought I'd start a thread here to hopefully document my progress and get some help with a project I've just finished (?) collecting parts for: converting my 1997 Ducati 900SS to fuel injection using a Speeduino setup.
The meat and potatoes is that I'm wanting to create a fuel-only system in the style of a Holley Sniper EFI or FiTech, wherein the carbs are replaced with throttle bodies, the fuel pump is upgraded, and a crappy factory crank signal is supplied to the computer. No/minimal modification to the engine required, spark will remain handled by the factory means (which are trash, but whatever).
The layout of the machine is a 90 degree L-twin with two VR sensors triggering two spark controllers that batch fire the two spark plugs. The spark computers simply trigger the spark every time a leading edge hits one of the VR sensors (it actually switches between leading edge and trailing edge depending on the RPM to attain the world's most rudimentary spark advance). The "trigger wheel" has a single trigger. My thought was hooking the Speeduino in parallel with a jumper harness (it uses simple two-pin Honda-style connectors which I have plenty), plopping in a VR conditioner, and then... doing something. These fuel-only setups don't appear to be super common so finding other people who have documented using these hacky OEM setups. Concerns have been levied about batch firing the injectors causing cylinder wash. I'm not sure if that would be a concern or not. I'm not even certain for sure if this is a supported configuration (wheel with 1 trigger, two VR sensors 90 degrees apart, sequential fire via some sort of cranking algorithm?).
The goal is to have a fairly basic Alpha-N setup with the built-in MAP sensors providing a baro skew for various altitudes/ambient barometric pressure. Eventually I'd like to have closed-loop cruising using a wideband O2 sensor installed in the exhaust (I don't count this as "modifying the bike" because I'd do this if I stayed with carbs anyways), potentially with fuel trimming functionality similar to most modern cars to account for variances in fuel. I also want it to be fully reversible with no modifications to the bike or its wiring, plugged in entirely using jumper harnesses.
Currently the bike has some garbage constant-velocity Mikunis which seem to be an exercise in "how complicated can we make a carbeurator?" and generally work ok some of the time maybe if they feel like it but I don't ride this bike very often and I'm bored so here we are.
Intake manifolds, fuel pump, and throttle bodies were sourced from a 1999+ factory fuel-injected Ducati, which differed in that it had an actual trigger wheel in the engine for more precise spark and fueling. It did operate on an Alpha N principle and I believe it batch fired the injectors as well. By all accounts it was pretty damn primitive.
Current questions:
Can I simply hook up the Speeduino to the VR sensors in "parallel" with the CDI boxes?
Injectors are ground-triggered, right? 12v-injector-speeduino? Most diagrams show it that way but it seems to be one of those things it's assumed you already understand. I've done a bunch of tuning turbo Miatas on Megasquirt via TunerStudio but "from scratch" like this has me struggling to comprehend the basics.
Is my injector trigger strategy viable?
The meat and potatoes is that I'm wanting to create a fuel-only system in the style of a Holley Sniper EFI or FiTech, wherein the carbs are replaced with throttle bodies, the fuel pump is upgraded, and a crappy factory crank signal is supplied to the computer. No/minimal modification to the engine required, spark will remain handled by the factory means (which are trash, but whatever).
The layout of the machine is a 90 degree L-twin with two VR sensors triggering two spark controllers that batch fire the two spark plugs. The spark computers simply trigger the spark every time a leading edge hits one of the VR sensors (it actually switches between leading edge and trailing edge depending on the RPM to attain the world's most rudimentary spark advance). The "trigger wheel" has a single trigger. My thought was hooking the Speeduino in parallel with a jumper harness (it uses simple two-pin Honda-style connectors which I have plenty), plopping in a VR conditioner, and then... doing something. These fuel-only setups don't appear to be super common so finding other people who have documented using these hacky OEM setups. Concerns have been levied about batch firing the injectors causing cylinder wash. I'm not sure if that would be a concern or not. I'm not even certain for sure if this is a supported configuration (wheel with 1 trigger, two VR sensors 90 degrees apart, sequential fire via some sort of cranking algorithm?).
The goal is to have a fairly basic Alpha-N setup with the built-in MAP sensors providing a baro skew for various altitudes/ambient barometric pressure. Eventually I'd like to have closed-loop cruising using a wideband O2 sensor installed in the exhaust (I don't count this as "modifying the bike" because I'd do this if I stayed with carbs anyways), potentially with fuel trimming functionality similar to most modern cars to account for variances in fuel. I also want it to be fully reversible with no modifications to the bike or its wiring, plugged in entirely using jumper harnesses.
Currently the bike has some garbage constant-velocity Mikunis which seem to be an exercise in "how complicated can we make a carbeurator?" and generally work ok some of the time maybe if they feel like it but I don't ride this bike very often and I'm bored so here we are.
Intake manifolds, fuel pump, and throttle bodies were sourced from a 1999+ factory fuel-injected Ducati, which differed in that it had an actual trigger wheel in the engine for more precise spark and fueling. It did operate on an Alpha N principle and I believe it batch fired the injectors as well. By all accounts it was pretty damn primitive.
Current questions:
Can I simply hook up the Speeduino to the VR sensors in "parallel" with the CDI boxes?
Injectors are ground-triggered, right? 12v-injector-speeduino? Most diagrams show it that way but it seems to be one of those things it's assumed you already understand. I've done a bunch of tuning turbo Miatas on Megasquirt via TunerStudio but "from scratch" like this has me struggling to comprehend the basics.
Is my injector trigger strategy viable?