Page 5 - Combined_59_OCR

Results of Second Test of 1969 Fiarger 50Ojat Daytona Intermit Iona 1 Speedway

n Factor

Xt is well known that a great m
many rac*any factors effect the lap speed of a race
at Daytona other than changes in the car itself. kMost of these come under the
general heading of environental items : temperaturehumidity f. barometric pressure^
wind and track temperature. For the simpler conditions-of drag racing a^satis-
factory correction factor was developed for barometer^ temperature and humidity
everal years ago. rFor track racing the effects of weather are more complex, and
has been more difficult to develope a successful correction factor. Such a
actor has now been developed^ and it appears to do a good job of correcting the
observed lap speed for temperature and humidity. It turns out that barometric
pressure is of very small importance9 since an increase in barometric pressure in­
creases both engine power ariLaerodynaraic drag by a similar amount. While the
basic correction factor equation (Joes allow for barometric pressure» the effects
of the range of barometer changes normally experienced is too small to be of any
ignifinance.

An example of the usefulness of the correction factor^is shown below,
corrected and uncorrecte.sk speeds a or three different runs with the
in the same condition

Observed
Speed Humility

189.13 1-0050
11:45 JM 188.44 1.0100
12«45 PM 1.0111

it ion th a spread of 1.1(4 mph between these three
where the spread is only 0.22 mph for the corrected numbers. These three runs
were made'before the final baseline was achieved., and are slower than the baseline
since the carburetor was reaching WOT3 and there were some air leaks arou
the front bumper and grille that had not as yet been sealed. There are other ex­
amples during khis test of the at‘ility to return to a corrected speed very close to
he original under different weather conditions where the observed speeds vary
jjnif

rhe corrections are all mace to 60° F anti 0 hum id i n checking weather data
for Daytona tests and races in the past year we find that the correction factor was
slight!j less than 1 for the days before the first day of qualifying in February
1968. On.the qualifying day^he correction factor was 1.0044. This factor corrects
V/
(inserts qualifying speed dr 183^ 53 mph in car 046 i-s corrected to 184.34 mph. For
the first day of qualifying for the July race the correction factor, was 1.0168^ so
that Charlie GlotgbaclVs pole winning 185.16 ©ph is corrected to 188.27 mph> an in­
crease of 3C 11 mph. Lee Roy Yarbrough6 s fastest qualifying time of 187.05 mph is
During the various tests tun at Daytona during the past
«
year we nave seen 1.0067 and 10183* a difference