Mr. Gasket 8703 Hot Rod Calculator - Manual (Page 25)

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* Recall that ADI is a ratio, expressed as a percentage, of the current
air’s density to that of MSA. At the Auto Club Raceway under the afore-
mentioned weather conditions, the air’s density is about 94.6% of that of
MSA. Notice that the current air conditions at 1,025 feet above sea level
are theoretically the air conditions at an Elevation of about 1,873 feet
above sea level.
In the next example, you are at the Firebird International
Raceway, just outside of Phoenix, Ariz. The track’s Elevation is
about 1,082 feet above sea level. The current local measured
weather conditions are an unseasonably chilly 33° F, absolute
Pressure of 28.77 inHg, and a relative humidity of 64% at 8:30
a.m.
Calculate the Air Density Index (ADI) and Density Altitude.
KeysTroKe disPlay
 0.
1. Enter current local measured weather conditions:
 TeMP 33. °f

(Pressure)
P-abs 28.77
inHG
 rH% 64.
%
2. Calculate ADI and Density Altitude:
 ElEV 0.
 adi 101.002
%
*
 d-alT - 341.909
f
* While these weather conditions at Firebird International Raceway are
unlikely, this example demonstrates an ADI value of over 100%, which
is certainly a possible situation. As stated previously, air density is typi-
cally over 100% when temperatures are well below 60° F.
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