uaEFI
Posted: Mon Mar 31, 2025 12:58 am
Hello, doing bike EFI retrofit using uaEFI. Tried to use stock VR sensor (I added digital hall sensor to camshaft for phase). Stock trigger wheel is 6mm thick/wide with 4 short 1 long teeth. After several attempts to get 24 teeth trigger wheel from 8mm mild steel on cnc laser best result was taken and post processed on lathe. It was not possible to find such speed/power config on laser so each tooth is perfect. Tried stock sensor and the best wheel I could cut on lathe. Lathe is vector VFD controlled with hall sensor for rpm measurements. 100rpm was 300mv p-p sine, 2200rpm was 24V p-p, and I suppose it will be ~130V p-p at 12000 rpm (hard limit of engine).
Oscilloscope showed clean sine BUT due to few tooth having slightly variable shape some sines are bit phase shifted as seen on video.
So I have some questions:
1. Should I limit voltage via some voltage divider to not burn uaEFI circuits with 130V sine input? Should I increase gap with VR so voltage is lower everywhere? If gap increased 100rpm will be not even 300mv p-p will uaEFI catch that at all to start up engine?
2. Can camshaft sensor send trig signal at some weird angle before TDC of some cylinder? say 137.67 deg BTDC #3? can it be entered into config or I need to have it as close as possible to 0.0deg TDC of some cylinder to make things happen? I will not use missed tooth on trigger wheel on crank, is it ok?
3. What with phase drift of sines? Does uaEFI calculates time between two tooth to use as input for derivate/integral calculations in engine math model to get idea of accelaration after combustion of each cyli der to check for misfire and/or balance them(cylinders) out via spark advance and/or injection tweak? Are there any theoretical/practical numbers of accepted phase drift when internal digital filters can coupe with trigger wheel tooth position deviations? Seems like there is some IC in input for VR, does it filter/normalize/average signals?
Oscilloscope showed clean sine BUT due to few tooth having slightly variable shape some sines are bit phase shifted as seen on video.
So I have some questions:
1. Should I limit voltage via some voltage divider to not burn uaEFI circuits with 130V sine input? Should I increase gap with VR so voltage is lower everywhere? If gap increased 100rpm will be not even 300mv p-p will uaEFI catch that at all to start up engine?
2. Can camshaft sensor send trig signal at some weird angle before TDC of some cylinder? say 137.67 deg BTDC #3? can it be entered into config or I need to have it as close as possible to 0.0deg TDC of some cylinder to make things happen? I will not use missed tooth on trigger wheel on crank, is it ok?
3. What with phase drift of sines? Does uaEFI calculates time between two tooth to use as input for derivate/integral calculations in engine math model to get idea of accelaration after combustion of each cyli der to check for misfire and/or balance them(cylinders) out via spark advance and/or injection tweak? Are there any theoretical/practical numbers of accepted phase drift when internal digital filters can coupe with trigger wheel tooth position deviations? Seems like there is some IC in input for VR, does it filter/normalize/average signals?