[s-cars] From the Horses Mouth at DynoJet (SAE)

[Cody Payne]

"The correction factors that we use in our dynamometer software are not
valid with forced induction applications. The most popular correction
factor, SAE CFJ1349 JUN90 and J1995 JUN95, does not account for the
conditions present in boosted applications. Atmospheric pressure is the
major component of this calculation, and anything that varies from the
standard (29.235 inHg) can easily be corrected for NA applications. When
you are forcing an "artificial atmosphere" into your motor, these
standards go out the window. 

Technically any boosted car should be viewed as uncorrected if you want
to compare apples to apples. If we had a correction factor that just
took into account temperature and humidity, that may make things easier
to compare in boosted applications. If you are forcing 1 atmosphere
(14.7 psi) in your motor at 6,000 feet, or 1 atmosphere at 100 feet,
that's really the same difference.................IF you are measuring
manifold ABSOLUTE pressure, it's absolute, don't rely on a standard
boost gauge to give you an absolute value. Regards, 
---------------- 
Dan Hourigan"