Mat
Moran Motorsports
Temperature Effects
The following
chart shows
temperature against quarter mile elapsed time (E.T.) for many of the
passes that I made from July to September 2004.
The
temperature
is in degrees farenheit and is actually the average of the air
temperature and the temperature of the coolant in the intercooler
circuit (usually between 0 and 20 degrees above the air temperature.)
This seems to give me the best straight line correlation.
You can see that there's a good correlation between temperature and
E.T. If you draw a "best fit" line through the points and extend it
down until it crosses the bottom axis you can see what the temperature
would need to be to make a sub 13 second pass without making any
further performance enhancements. I guess somewhere around 40 degrees.
Another interesting thing that you can see is that most of the runs on
7/4/2004 seem to be on the fast side, even taking into acount the low
temperatures that day. 7/4/2004 was
the only time that I raced without a spare tire or jack in the car.
That's one obvious way to pick up a bit of performance.
Finally, the slope of the imaginary straight line through the points is
around 0.01 seconds for each degree of temperature change. With a
4000 pound car producing around 400 horsepower this would indicate that
you gain about 1 horsepower for each degree drop in temperature.