<VV> BMEP was octane

[Padgett]

> >No, no, no!  Brake Mean Effective Pressure (BMEP) is just brake torque
>(normalized for displacement). <

Wonderful: someone who understands what I have been talking about. Of 
course you are correct (and why I usually referred to "peak chamber 
pressure". BMEP is more a function of VE (volumetric efficiency) and charge 
density which results in how much torque you produce. Or maybe just brane fade.

 >The actually burn *rates* for high octane fuel really are not that much
different from low-octane. <

Burn rates are a function of both octane (agreed, not much but then we are 
really talking small changes in octane, only about a 6% range, more 
important is the elevated flash point) and charge density (velocity 
increases with density), which varies over a much greater range - why we 
need vacuum advance.

 >Actually, that is rather over-advanced on most engines.  Typically loction
of peak pressure is around 13-15 deg atc<

Agree, have not studied the Corvair geometry that closely, yet. Why I said 
it really needs to be determined on a dyno. Would expect that someone has 
done that already. GM used to produce "standard engine test" books with 
graphs on every engine it had.

Padgett.