Micron 5 RPM accuracy

[J Weida]

Will a Micron 5 ready the RPM on a pinto correctly?
Mine is jumping all over the place.

[LarryWinkelman]

Will a Micron 5 ready the RPM on a pinto correctly?
Mine is jumping all over the place.

Short answer is maybe, from what I've been told. I asked an AiM dealer about it when I was looking at an older FC last year and he said probably not. Something about the difference between kart and car ignition, although I didn't explore in detail.

That said, see also here for success stories:
https://www.apexspeed.com/forums/sho...and-a-Mychron5

[Purple Frog]

Probably a better chance with Petronix in the distributor than points.
Always check the grounds. Just saying.

[Mark_Silverberg]

Not on a FC but on a FV I found the Mychron 5 had very poor RPM accuracy below about 2800 rpm and the signal was quite noisy - on the track above 3000 RPM the signal is quite good.

One key point is to try to keep the rpm lead away from any other wires so it does not pick up any other induced currents or frequencies.
When wrapping the wire around the spark plug use no more revolutions than specified - more is not better - try to keep the wire loops tightly wrapped and touching each other side to side - like a completely collapsed spring - see if that helps.

It is a shame because the Mychron 5 actually has some really good predictive lap timing features and would be an excellent formula car dash - all it one if it had the ability to log pressure as well as temperature.

[Rick Kirchner]

there's a device that they sell that cleans up the pulse so that its more of a square wave. If you use the low side of the coil right into the dash unfiltered, you'll eventually kill the dash.

Unfortunately, that device is virtually a fuse. I built a large protection circuit for it and also switch the power to it. If it blows, the chip inside is only about $1. But you need specialized tools to replace it since its so small.

I reverse engineered the circuit so it can be built with 1/4w resistors and other normal sized components, but haven't gotten around to building any.