Mr. Gasket 8703 Hot Rod Calculator - Manual (Page 22)

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density altitude
Density Altitude is an MSA Elevation that has the same air
density as the current local measured weather conditions.
Meaning, your physical Elevation might be 4,000 feet above
sea level, but the current air conditions are like a “theoreti-
cal” perfect day at 5,000 feet. Density Altitude is simply a
corrected Elevation, and is calculated using the current local
measured weather conditions entered into the calculator.
air density index
Air Density Index, ADI, is a ratio (expressed as a percentage)
of the current air’s density to that of MSA. The ADI at MSA is
100%. ADI is calculated using the current local measured
weather conditions entered into the calculator. once you
have established an air/fuel ratio for the current track and
weather conditions, calculate and record the current ADI.
As a rule, ADI will be less than 100% for Elevations above
sea level as well as for temperatures above 60° F.
Conversely, ADI will be more than 100% for temperatures
below 60° F.
As a guideline, ADI can be used to tune your engine’s air/
fuel requirements when conditions change from your base-
line conditions. For each percentage point the current ADI is
above your recorded baseline ADI, your engine will require
that much more fuel. Conversely, for each percentage point
the current ADI is below your recorded baseline ADI, your
engine will require that much less fuel to maintain the same
level of performance.
(cont'd)
UG8703E-B-inside.indd 20 3/3/2010 3:03:57 PM