<<<<<<<<<<<<<<<<--->>>>>>>>>>>>>>>>
          <<  Lancair Builders' Mail List  >>
          <<<<<<<<<<<<<<<<--->>>>>>>>>>>>>>>>
>>
<<The reason for my
recent examination of the engine running parameters is my use of the Lasar
electronic ignition that changed the way fuel and air are converted to power
(heat).  Since more combustion occurs in the cylinder and less burn in the
exhaust pipe I am seeing the forecast 80-100 degree reduction in EGTs and a
20 degree rise in CHTs.>>

I'd like to clarify and maybe correct some assumptions.  The LASAR or any
other ignition won't "change the way fuel (is burned)."  What it does is
advance the ignition timing at part loads.  This moves the peak combustion
pressure closer to TDC, increasing the pressure and therefore torque.  With
higher cylinder pressures come higher gas temperatures along with increased
rate of heat transfer to the cylinder - hence the higher CHT's.  At the same
time, slightly more of the heat energy is converted to work, meaning that
less heat is left in the gas when the exhaust valve opens.  For any engine
combustion is essentially completed inside the cylinder (Yeah, I know, but I
said "essentially" and there might always be something visible coming out
the exhaust if the stack is short enough).  So in summary, with an advanced
spark slightly more heat goes into the cylinder head, slightly more into
work and therefore slightly less in the exhaust.

Gary Casey
ES project


>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
LML website:   http://members.olsusa.com/mkaye/maillist.html
LML Builders' Bookstore:   http://www.buildersbooks.com/lancair
Please remember that purchases from the Builders' Bookstore
assist with the management of the LML.

Please send your photos and drawings to marvkaye@olsusa.com.
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>