[ATI93]

Ah, okay, I saw while googling that with megasquirt you should use teeth divisible by number of cylinders. And yeah, the wheel size is a bit problematic, that is why I was thinking about the 32 tooth wheel first, but with this new info Ill try to design a 30 tooth wheel, and even if it wont fit in the distributor cap, I can just make the trigger wheel bigger and make some custom cap/cover. Read in some hall sensor datasheets that teeth need to be at least 2 by 2mm, which is quite small, will probably go a bit on the safe side. Thank you mate, you are a saint

[Rednaxs60]

As I mentioned interesting thread. Learned something new. Good luck and will be following.

[LPG2CV]

You could also consider an optical sensor.

[PSIG]

Ah, okay, I saw while googling that with megasquirt you should use teeth divisible by number of cylinders.

One rule is to not use technical info for any system but the one you are using. It can not only be wrong, but very frustrating. While "EFI" works similarly for all EFI systems, how each gets that done can be different. That is MegaSquirt info. Speeduino is different, and for the Missing-Tooth (Cam) decoder, is teeth evenly divisible into 720°. Others are required to be evenly divisible into 360° (generic decoders). The Non-360 decoder is an example highlighting an exception to this normal requirement. Follow the spec's for your decoder.

[ATI93]

Thanks for the info, at first I thought they are basically the same systems, just with different board layout and chip, but I see now each one can be a bit different.

And for the optical sensor, I thought about that, much smaller package, but as the car will see track days, reliability might be an issue on hot days. Found some datasheets for optical sensors that stated max temp to be 85 °C, and it has a diode for a light source which arguably can last very long, but Hall or VR should last more. At least that is what I found out so far.

[LPG2CV]

I wouldn't worry to much about reliability.

In 2CV racing, the racing spec is to use a Lumenition as a replacement for the points sytem. This is led based.

I have never heard of a 2cv Lumenition failing. There is a 2CV 24 hour race each year. They may blow up engines (I think the record for an engine change is 25 minutes), but they never have issues with Lumenition.

I think my Lummy must be 30 years old.