User guide

HOT ROD CALC™ — 25
To translate a fuel correction index to a new jet number, recall
your baseline was recorded with #78 jets, which according to the
Appendix B – Holley Jet Chart and Jet Orifice Area Conversion
Chart, have a flow of 645 cubic-centimeters per minute. Recall
your fuel correction index is about 89%.
6. Calculate a new flow requirement:

574.05
Using the chart in Appendix B, the closest flow number to 574 is
the 566 cubic-centimeters per minute flow which corresponds to
a #75 jet, which would be a change of three jet numbers down (in
this example, density altitude has gone up so it stands to reason
that a leaner jet number may be required). A conservative change,
however, would be to go from the #78 to the #76 which has a flow
of 587 cubic-centimeters per minute.
Calculating Water Vapor Content
Using a different set of track and weather conditions at Top
Gun Raceway, let’s calculate water vapor content (water vapor
pressure, saturation water vapor pressure, and dew point).
The track’s elevation is about 3,963 feet above sea-level. The
current local measured weather conditions are 73° F, absolute
pressure of 25.88 in Hg, and 14% relative humidity at 10 a.m.
KEYSTROKES DISPLAY

0.
1. Enter current, local measured weather conditions:

TEMP S 73. °F

(Absolute Pressure) P-ABS S 25.88 INHG

RH% S 14. %