The underside of the piston is only working as a supercharger in the case of a 2T lawnmower engine.
Around BDC in a race engine the pipe diffuser sucking on the transfers creates a huge depression in the case , and it is this that begins to open the reeds.
If the inlet length is tuned correctly for the rpm , it then produces a positive pressure ratio at the same time on the opposite side of the petals.
Near TPC , the reeds are open , and the piston rising has had almost nothing nothing to do with this state in the 2T cycle.
This scenario is the naturally occurring " supercharging " effect in a 2T race engine.
This gives the lie to some peoples idea that there is " flow " thru the intake , into the case , and out thru the transfer ports - doesn't happen.
The total amount of mixture stored in the transfer ducts is greater than the swept volume of the cylinder , so it is this that is drawn upon by the pipe action - even accounting for a Volumetric Efficiency above 100%
It is only the pressure differential across the ports, at the bore , that is transmitted to the case.
Ive got a thing thats unique and new.To prove it I'll have the last laugh on you.Cause instead of one head I got two.And you know two heads are better than one.
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