What is 100% VE?

[Jeremy Edmondson]

> 100% VE is not possible without some form of supercharging (in which case
> you can get > 100% VE) - ignoring for now issues of tuned intakes/exhausts/etc.

Ture, but you cannot ignore the effects of exhaust/intake tunning as these can easily 
push the VE to greater than 100% and the designed operating point.  There are numerous 
examples of naturally aspirated race engines achieving better than 100% VE.
 
> > I have this sentence stuck in my mind, I think I read it on this
> > list a week or two ago.  "An engine peaks in VE at its torque
> > peak."  That's true right?
> 
> Not as far as I know.  Generally, for a normally aspirated engines, VE
> decreases pretty steadily as RPM is increased from 0.  Again, this ignores
> charge recovery that can occur at certain RPM ranges from tuned intakes and/
> or exhausts.
> 
> What I think IS generally true is that an engine peaks in overall
> efficiency (its efficiency at turning gasoline into horsepower) at its
> torque peak.

Typically peak conversion efficiency and peak VE cccur at max torque for the simple 
reason that this is the 'tunned' operating point of the engine.  If the cylinder 
filling is at a maximum then the precombustion pressure will be the greatest and hence 
the maximum torque will be produced.  Also we know that the greater the pre combustion 
pressure the more effective/efficent the combustion.