ET Prediction Computers:
ET Predictor II Computer
- Sharp PC-1270
# ET-1000 ET Predictor II Computer (V6.07)
(Refurbished) New PC-1270's
are no longer made by Sharp)
The ET Predictor II computer,
will enable you to properly manage air/fuel ratios for the current air density,
track vehicle performance or modifications, and accurately predict elapsed time
and throttle stop settings according to varying weather conditions. Included are
programs to calculate Air Density, Horsepower Correction, Density Altitude, Vapor
Pressure, Water Grains, Engine Displacement, Compression Ratios, STP Corrected
Elapsed Time, Run Completion, Corrected HP from MPH, HP Corrected Vehicle Weight,
Throttle Stop Factor, and our exclusive Run Segment Analysis program. The
next best thing to having an on-board computer. Comes with complete instructions
and ET prediction hints and tips. Nothing is more accurate for ET Prediction!
enter the air conditions from your weather station or weather gauges into the
program. We have weather instruments and weather stations available here on the
Gasoline, Methanol, and E85
Fuel Modes (E85 Fuel Mode Available in
Drag racing programs calculate:
ET Prediction (60, 330, 660, 1000, and 1320 foot)
Throttle Stop Prediction
Air Density Index
Horsepower Correction Factor
*-Water Grains Per Pound -*
Run Segment Analysis program, the next best
thing to having an on-board computer!
Predicted 330' ET
Predicted 660' ET
Predicted 1000' ET
Predicted 1320' ET
Inches HG to Altitude
HP from MPH
The ET Predictor software is the most accurate ET Prediction and Weather Station
software available because it uses Horsepower Correction and does not predict
from an average of stored runs. The ET Predictor provides a Horsepower Correction
Factor (HCF) and Air Density Index (ADI) using a standard of 0 Elevation, 29.92
In Hg Barometric Pressure, 60 degrees F Temperature, and 0 percent Relative Humidity.
Under these conditions, the HCF equals 1.0000 and the ADI will equal 100.0 percent.
The HCF and ADI compensate for pressure, temperature, and relative humidity. Conditions
that improve the HCF and ADI are cold air, high air pressure, and low humidity.
program uses the Elevation, Barometric Pressure, Temperature, and Humidity, to
calculate the current Horsepower Correction Factor (Current HCF), Air Density
Index (ADI), and Density Altitude (DA), Dew Point, and Vapor Pressure. The formulas
used in this program are the same ones used in our ET Predictor II hand-held computers,
ET Predictor software, and RaceLog Pro software.
Elevation - Range:
-3,000 to +26,000 Feet - Elevation is only used if you are using an altimeter
or a corrected barometer. If you're using an uncorrected barometer reading absolute
pressure, always enter 0 for the elevation. If you have an altimeter, calibrate
it to 29.92 In Hg and enter the reported altitude as the elevation. If you are
using an analog barometer and your altitude requires that you use a corrected
barometer, then you should always enter the number of feet equal to the amount
of correction when you calibrated the barometer. Digital barometers and altimeters
measure absolute pressure, without any need for correction, so their use is preferred.
Barometer - Range: 12 to 35 Inches Hg - If you're using a barometer
to obtain the air pressure, enter the barometric pressure from the gauge. When
using an altimeter, always enter 29.92 for the barometric pressure.
Temp F - Range: 10 to 130 degrees F - Enter the temperature from a digital
thermometer or other temperature gauge. From round to round, temperature changes
are apt to affect performance more than any other variable. RH% - Range: 0 to
100 Per Cent - You can use a digital hygrometer to find the relative humidity.
At low temperature, relative humidity has the least effect on performance. However,
at high temperatures, the effect is much greater. For example, 50% RH at 60 F
will result in a .01 loss in power, while at 90 F the addition of 50% RH equals
about a .03 loss in power. Changes in temperature are also more critical under
following is more information on the resulting calculations:
HCF (Current HP Correction Factor) - The Horsepower Correction Factor is computed
using the current weather conditions that you enter. In other words, the HCF equals
the current elevation, barometer, temperature, and humidity. When the HCF is higher,
less horsepower is produced, and the car will run slower. So, the lower the HCF
is, the faster the car will run. You can use the HCF to determine the variance
in horsepower or torque that is being produced under different weather conditions.
For example, if your engine produces 400 horsepower with an HCF of 1.012, it will
produce 404.80 horsepower at sea level conditions (STP) or 1.0000 (400 x 1.012=404.80).
Vapor Pressure - Vapor Pressure is the exact portion of barometric
pressure that is present due to Relative Humidity, or moisture, in the air. Vapor
Pressure is used in calculating the horsepower correction.
(Air Density Index) - The Air Density Index (ADI) is the computed ratio of the
current density to that of STP with STP having an index of 100 percent. This factor
is used to determine the correct jetting or pill size required under varying weather
conditions. The higher the ADI, the more air there is available for combustion.
Therefore, more fuel must be burned to maintain the correct air/fuel ratio. When
using gasoline, a four (4) percent change in the ADI will usually necessitate
a change in jet area in order to maintain the same level of performance. Holley
jet sizes are about 4 percent apart in flow area. If the ADI goes up four (4)
percent, for example 100.0 to 104.0, increase all jet sizes by one number. And,
if the ADI goes down four (4) percent, for example 100.0 to 96.0, decrease all
jet sizes by one number.
Density Alt (Density Altitude) - Density
Altitude (DA) is the current air density expressed in feet of elevation. DA is
also known as the corrected or relative altitude. DA is not scientific and is
very inaccurate. Therefore we do not use this factor in ET Prediction. We only
report this value for information purposes only.
Dew Point -
Dew Point is the calculated temperature at which condensation (moisture) occurs
based on the entered air conditions. Dew Point will tell the racer when the traction
on the race track will worsen due to condensation. When the actual measured air
temperature matches the Dew Point temperature, the race track will be wet.
about whose weather computer to buy? To find out the cold hard facts about weather
computers, read our newsletter on this subject by clicking here.
We can repair all Sharp PC-1270 computers.
Also we can reprogram most Sharp PC-1270's and all Sharp EL-5500
III calculators to ET Predictor II specs for a fee of $125.00. This
includes all of these outdated (and inaccurate) units from:
your PC-1270 can be reprogrammed depends on what removable program card it has.
There are Sharp RAM cards, P*ROM Eprom cards, and Pygmy Eprom cards.
of these Sharp RAM Cards can be reprogrammed:
RAM CARD 8 - Part # CE-212M
RAM CARD 16 - Part # CE-2H16M
32 - Part # CE-2H-32M
RAM CARD 64 - Part # CE-2H64M
the (gray) P*ROM brand cards can be reprogrammed but we must test them in our
machine to find out whether they are protected or not.
of the (black) Pygmy brand Eprom cards can be reprogrammed.
We can also
reprogram all SHARP EL-5500 III computers to ET Predictor II 6.06 specs. Call