lotus7racer

Can someone tell me how many pulses per engine cycle in S2000 engine?

slalom44

If I understand your question correctly, you want to know how many spark plug firings take place with each engine revolution.

The answer is two. Each piston fires on every other revolution, and there are four cylinders. Therefore after two revolutions each spark plug fires once.

lotus7racer

Slalom---I think you are right (2).

I got confused on what I read below. I think they are talking of exhaust gas pulses instead of pulse per revolution (sparkplug firing per rev).

I read and interpreted this wrong.

Your exhaust system is designed to evacuate gases from the combustion chamber quickly and efficently. Exhaust gases are not produced in a smooth stream; exhaust gases originate in pulses. A 4 cylinder motor will have 4 distinct pulses per complete engine cycle, a 6 cylinder has 6 pules and so on. The more pulses that are produced, the more continuous the exhaust flow. Backpressure can be loosely defined as the resistance to positive flow - in this case, the resistance to positive flow of the exhaust stream.

Thanks

slalom44

Ahh.... I see where you're coming from now.

There are two engine revolutions to a complete enging cycle in a 4-stroke engine, so your last paragraph is correct. The more cylinders, the more continuous the exhaust flow at the same engine RPM. There are two exhaust pulses per revolution in our engine.

SpitfireS

The exhaust pulses come in the same order as the spark plugs.
1-3-4-2

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^ bingo