Leita litt på mrm forumet så klipper litt derfra:
The Sm4 tacho output does not do scaling, but it is same as "events per cycle". So on some Volvo 6-cyl engine with stock tacho that is 4-cyl (even 5-cyl car has 4-cyl tacho) I set up "events per cycle" to four, given four pulses per 2 crank revs.
Tråden det kommer fra: http://www.mrm-racing.se/forum/showthre ... ight=tacho