Replacement Tacho
Discussion
Quick question.
I have a replacement tacho from not very speedy cables and it appears to be a re-cased aftermarket unt that I need to set up using a bank of DIP switches inside it.
The switches are to set the tacho to know how many pulses per revolution it should see so here is the question.
How many pulses per revolution should it see with our cars ignition set up, I am assuming 8 as it is a 8 pot with wasted spark ignition but is this assumption correct?
I have a replacement tacho from not very speedy cables and it appears to be a re-cased aftermarket unt that I need to set up using a bank of DIP switches inside it.
The switches are to set the tacho to know how many pulses per revolution it should see so here is the question.
How many pulses per revolution should it see with our cars ignition set up, I am assuming 8 as it is a 8 pot with wasted spark ignition but is this assumption correct?
ajp fires every 75 and 105 degrees of the crank, 8 events every 2 rotations. when it fires it fires 2 cylinders at once,one bang and one into the exh pop, but it is still only 1 event as the Kv leaves the coil down one lead jumps the gap into the block then back up the plug and lead that's attached to the other side of the same coil to return as a negative, i dont think your tacho will see this so wont count these "waste?" events. Should be 8 but If its asking how many per 360 then its 4.
Byker28i said:
Hang on, the ajp fires two cylinders at the same time? I thought the firing order is 1,4,5,2,7,6,3,8, so 8
each cylinder takes 2 revolutions per 'cycle' suck/squeeze being one rev and then bang/blow taking a second rev.
Wasted spark sends a bang on the suck part of the cycle on one cylinder, which is wasted and does nothing. While at the same time send a bang to the 'other' cylinder which is used to fire the fuel/air mix.
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