Please Explain Timing Etc.
08-14-09, 10:26 AM
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Please Explain Timing Etc.
Over the years, I've tried to learn more and more about engines, and how things work. I've grown pretty knowledgable about much of it, but tuning has always intimidated me. I've simply avoided diving in to it for fear of not understanding it well enough. I would like to learn more about Wide Band O2, it's purpose in tuning as well as everything there is to know about timing and duty cycles. I know that timing is has to do with spark, etc. But that's about it.
I was at a car show recently and some friends werre discussing how they have manipulated there timing setups in relation to AI etc, and all I could do is nod my head and act like I knew what the hell they were talking about.
Please point me in the right direction.
Take Care
I was at a car show recently and some friends werre discussing how they have manipulated there timing setups in relation to AI etc, and all I could do is nod my head and act like I knew what the hell they were talking about.
Please point me in the right direction.
Take Care
08-20-09, 06:42 AM
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In simplest terms:
Timing is the point in the engine cycle that the spark is fired. It's expressed in degrees relative to a known point in the cycle.
As the rotary has 2 plugs per rotor, leading and trailing, the leading is fired first - followed by the trailing plug. The engine would run on the leading only, but the trailing plug helps clean up the emissions and provides a smoother burn (there is a pinch off of the combusition chamber as it passes across the plugs - effectively dividing it into 2).
Split is the difference in timing between the leading and trailing plugs. Running no split means firing both plugs together.
Advancing and retarding timing are simply firing the plugs earlier or later respectively.
It's normal to increase the advance with increase in revs to give the mixture more time to burn, but there is a limit to this advance because you don't want to fire too early and try and make the engine go backwards.
It's normal to retard the timing with increase in boost to prevent detonation. Injecting water or Alcohol will change the burn charateristics allowing a little more advance and hence a bit more power.
That's very over simplified - there are a lot of factors to consider - but that should help you get your head around it.
Timing is the point in the engine cycle that the spark is fired. It's expressed in degrees relative to a known point in the cycle.
As the rotary has 2 plugs per rotor, leading and trailing, the leading is fired first - followed by the trailing plug. The engine would run on the leading only, but the trailing plug helps clean up the emissions and provides a smoother burn (there is a pinch off of the combusition chamber as it passes across the plugs - effectively dividing it into 2).
Split is the difference in timing between the leading and trailing plugs. Running no split means firing both plugs together.
Advancing and retarding timing are simply firing the plugs earlier or later respectively.
It's normal to increase the advance with increase in revs to give the mixture more time to burn, but there is a limit to this advance because you don't want to fire too early and try and make the engine go backwards.
It's normal to retard the timing with increase in boost to prevent detonation. Injecting water or Alcohol will change the burn charateristics allowing a little more advance and hence a bit more power.
That's very over simplified - there are a lot of factors to consider - but that should help you get your head around it.
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