increase in RPM
Hi,
I had a very similar experience. I was running on dual pmags with the electric vans tachometer driven from the tach drive. I installed an EI commander and saw an increase of 100 plus RPM from the previous tacho.
This concerned me because I run a Sensenich prop limited to 2600RPM, obviously if the old set up was reading 100 rpm too low I could have busted the limit without knowing.
I have to confess that even though I took my optical tester up to check on the new numbers I have not yet tested it....... but will in the next few weeks. I never go above 2400 anyway.