Difference in between digital and analogic rotors..HELP
- Thread starter quicksand
- Start date
the Malossi ignition is Digital it has a Micro-processor inside it 
and here 50cc zip race some more thoughts. When the compressed mixture inside a cylinder is ignited it takes time for the flame front to reach the piston and for the expanding gases to start pushing it down. The time that this takes changes according to a number of variables such as mixture strength, how well the cylinder has filled (dependent on volumetric efficiency and throttle opening), compression ratio and combustion chamber shape. Given the same circumstances of mixture strength, cylinder filling and CR, the time taken for the mixture to fully ignite and burn is the same regardless of engine speed. At increasingly higher RPM however, the time available for this burn to take place is correspondingly less, so it follows that you have to start burning the mixture earlier in order for it to push on the piston at the right time. This is the basis for increasing ignition advance.
Too much of this and the burning mixture hits the piston as it rises (pinking or pinging), too little and the flame front reaches the piston far too late and does not do a good job of pushing the piston down and the engine behaves like a herd of turtles.
and here from the Eric Gorr website
AFFECTS OF THE IGNITION TIMING
Here is how changes in the static ignition timing affects the power band of a Japanese dirt bike. Advancing the timing will make the power band hit harder in the mid range but fall flat on top end. Advancing the timing gives the flame front in the combustion chamber, adequate time to travel across the chamber to form a great pressure rise. The rapid pressure rise contributes to a power band's "Hit". In some cases the pressure rise can be so great that it causes an audible pinging noise from the engine. As the engine rpm increases, the pressure in the cylinder becomes so great that pumping losses occur to the piston. That is why engines with too much spark advance or too high of a compression ratio, run flat at high rpm.
Retarding the timing will make the power band smoother in the mid-range and give more top end over rev. When the spark fires closer to TDC, the pressure rise in the cylinder isn't as great. The emphasis is on gaining more degrees of retard at high rpm. This causes a shift of the heat from the cylinder to the pipe. This can prevent the piston from melting at high rpm, but the biggest benefit is how the heat affects the tuning in the pipe. When the temperature rises, the velocity of the waves in the pipe increases. At high rpm this can cause a closer synchronization between the returning compression wave and the piston speed. This effectively extends the rpm peak of the pipe.
and here 50cc zip race some more thoughts. When the compressed mixture inside a cylinder is ignited it takes time for the flame front to reach the piston and for the expanding gases to start pushing it down. The time that this takes changes according to a number of variables such as mixture strength, how well the cylinder has filled (dependent on volumetric efficiency and throttle opening), compression ratio and combustion chamber shape. Given the same circumstances of mixture strength, cylinder filling and CR, the time taken for the mixture to fully ignite and burn is the same regardless of engine speed. At increasingly higher RPM however, the time available for this burn to take place is correspondingly less, so it follows that you have to start burning the mixture earlier in order for it to push on the piston at the right time. This is the basis for increasing ignition advance.
Too much of this and the burning mixture hits the piston as it rises (pinking or pinging), too little and the flame front reaches the piston far too late and does not do a good job of pushing the piston down and the engine behaves like a herd of turtles.
and here from the Eric Gorr website
AFFECTS OF THE IGNITION TIMING
Here is how changes in the static ignition timing affects the power band of a Japanese dirt bike. Advancing the timing will make the power band hit harder in the mid range but fall flat on top end. Advancing the timing gives the flame front in the combustion chamber, adequate time to travel across the chamber to form a great pressure rise. The rapid pressure rise contributes to a power band's "Hit". In some cases the pressure rise can be so great that it causes an audible pinging noise from the engine. As the engine rpm increases, the pressure in the cylinder becomes so great that pumping losses occur to the piston. That is why engines with too much spark advance or too high of a compression ratio, run flat at high rpm.
Retarding the timing will make the power band smoother in the mid-range and give more top end over rev. When the spark fires closer to TDC, the pressure rise in the cylinder isn't as great. The emphasis is on gaining more degrees of retard at high rpm. This causes a shift of the heat from the cylinder to the pipe. This can prevent the piston from melting at high rpm, but the biggest benefit is how the heat affects the tuning in the pipe. When the temperature rises, the velocity of the waves in the pipe increases. At high rpm this can cause a closer synchronization between the returning compression wave and the piston speed. This effectively extends the rpm peak of the pipe.
50cczip racer
Well-Known Member
mrd/krd pvl digital use the same part no,s so are the same so buy the cheapest one , these are also good as they use the latest rotor with cooling fins on the back and use the split cdi/coil which is good for reliability
selletra mallossi is digital or you could buy the scooter attack italkit/selletra digital which is the same as the old polini selletra digital system at a very good price
all the ignitions will benefit from good ventilation via an open case to improve reliability / use of an additional earth strap and isolated anti vibration mounting of coil/cdi, i also use a thin nylon backplate to isolate from engine heat.
also regarding the original post (different ignitions and how they work)
eric gorr does not say what you say
he says advance(start the burn earlier/further from tdc) the timing in the midrange for hit and retard it(start the burn later/nearer tdc) for top end power and good overrev (look at the hpi curve again)
you say retard in midrange(flat power delivery) and go full advance at high rpm(destroying an engine) for top end
try it(go set your ignition to full advance if your so sure)
selletra mallossi is digital or you could buy the scooter attack italkit/selletra digital which is the same as the old polini selletra digital system at a very good price
all the ignitions will benefit from good ventilation via an open case to improve reliability / use of an additional earth strap and isolated anti vibration mounting of coil/cdi, i also use a thin nylon backplate to isolate from engine heat.
also regarding the original post (different ignitions and how they work)
Eoin70 said:
eric gorr does not say what you say
he says advance(start the burn earlier/further from tdc) the timing in the midrange for hit and retard it(start the burn later/nearer tdc) for top end power and good overrev (look at the hpi curve again)
you say retard in midrange(flat power delivery) and go full advance at high rpm(destroying an engine) for top end
try it(go set your ignition to full advance if your so sure)
