Page 2 - Combined_59_OCR

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Results of Second Test of 1969 Dodge Charger 500 at Daytona International Speedway

Discussion (cont9d)
mated to be about 10 horsepower better than the engine that was in car 046*
September test was run with Firestone tires of the same type as used in the July
4th race* This test was run with Goodyear tires that they say are the same as
their July 4th tire# although the tires had no compound identification on them.;
The bracing bars that bolt in across the rear corners of the engine compartment
were not installed in car 046 for the September tests but were in the new can
Fpr a baseline condition both of the cars had the grille completely blocked with
ta^es with all of the air for the radiator coming h.n through the hole under the^
bumper* On car 046 the air for the oil cooler came in through this same opening
while on the new car the oil cooler air comes in through the left Inboard head­
light opening* Gar 046 ran with a 2*94 axle ratio while the new car had a 3*07
axle ratio in baseline condition* There were also differences in weather con­
ditions between the two tests*

A correction factor has been developed that appears to make a rather good
" correction for weather differences^, so to remove this variable^ ail of the speeds
rad speed differences will be given corrected to 29*92” Hg dry air and 60° F unless
otherwise stated* The correction factor will be discussed in detail later in the
letter* The corrected speeds are^representative o speeds that should be obtained
with weather conditions that were Encountered. during, the first, week of practice in
February 1968&

The corrected best, speed obtained on car 046 fn September was 18%02 mph
186*18 mph observed)* The baseline speed for the new car is 191*34 mph for an
|/..verage of several runs (188*8 to 189*7 mph ^served speeds)* This gives an ad-
antage 2 *32 mph for the new car over car 046 0 An approximate breakdown of
this difference is:

Goodyear tires instead of Firestone in oh
Engine with 10 IS more^
Engine compartment braces in. place
3*07 axis ratio in place of 2*94
Underbody angle and"other changes
+2 <>32 raph

the exception of the underbody angle each of these differences was evalu-
ted in a separate teste The. differenced shown above can not be considered as
>mct9 but the general levels are believed to be valid*

To improve the speed of the c^r above the bast line several changes were tried*
le successful ones were::

Baseline^speed
Reducing air flow through kinder bumpe
opening
Heavy flywheel
9” wide rims

Several other items were also investigat
ar So /Th ere:

Uncovering the grille -2*60 mph
Long front spoiler (4n ground clearance)
Exhaust pipe ends cut off square