Sunday, April 11, 2021

Retro Review: Hot Rod Calculator

 Retro Review:   Hot Rod Calculator








Quick Facts:


Model:  8703, Hot Rod Calc

Company:  Mr. Gasket Co/Calculated Industries

Years of Production: 2009 - 2020*

Memory Registers:  1

Batteries:  2 LR-44

Operating System:  Chain

Display:  8 digits, unit indicators 

New Price: $80 retail; can be found on sale or clearance


* I can no longer find the Hot Rod calculator as a new calculator on the Calculated Industries website.  However, the Hot Rod app for both iOS and Android.  


Ladies and Gentlemen, Start Your Engines!


The Hot Rod Calc is a specialty calculator that emphasizes on automotive mathematics, with solvers and applications including:  


*  Air Temperature, Relative Humidity (Moisture), Elevation

*  Vehicle Weight, Elapsed Time (1/4 mile traveled in seconds), MPH

*  Bore, Stroke, RPM, Torque, Engine Displacement

*  Tire Ratio, Gear Ratio

*  Engine Volumetric Efficiency

*  Carburetor Size

*  Vehicle Weight, Horsepower, Elapsed Time

*  Conversions including length, area, volume, temperature, mass, velocity (speed)


You can download a PDF version of the manual here: 


https://documents.holley.com/mr_gasket_instructions_hot_rod_calculator_8703.pdf


The manual has several reference tables:


*  Drag Coefficients depending on the automobile type

*  Holley Jet Chart

*  Jet Orifice Area Conversation Chart


Keyboard


The calculator comes in a bright red Armadillo Gear case.   The keys are bright and colorful, with most of them sporting a warm color palette (red, orange).  The keys are responsive, but have a rubber feel to them.  I believe the keys are made to handle dirt and oils given the target audience of the Hot Rod Calc.


The case has a quick reference guide.


Example Calculations


The calculator is set to U.S. units (default)


Example 1:


Calculate Air Temperature given:

Elevation:  1,284 ft

Air Pressure:  30.12 inHg

Humidity:  33%


1284 [ Elev/ADI ]

33 [ Moisture ]

30.12 [ Conv ] [Air Temp] (Pressure)

[Air Temp],  Result:  55.4211 °F


Example 2:


Find the weight of a vehicle given:

It's horsepower:  426 HP

It's elapsed time:  9.73 sec to run 1/4 mi


426 [ HP ]

9.73 [ ET ]

[ Vehicle Wt ],  Result:  1999.7337 lb


Example 3:


Find the speed, in miles per hour, for an automobile traveling with the following specifications:

1st Gear:  3.26

Final Drive Gear: 3.03

RPM: 5800 (revolutions per minute)

Diameter of the tires: 26 inches


3.26 [ × ] 3.03 [ Gear Ratio ]

5800 [ RPM ]

26 [ Conv ] [ Gear Ratio ] (New Tire Dia)

[ MPH ],  Result:  45.417902  mph


Verdict


If you are into racing, hot rods, and automobiles, and you need a quick mathematics tool, the Hot Rod calculator is worth the investment.  Its user manual is a well written.  Now may be the best time to purchase one before the calculator becomes a rare item.  


Eddie


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