Brake Mean Effective Pressure
This is a calculation that gives you a measurement in bar (pressure). It is intended to be a way to compare engines and their output. It gives you output with respect to engine size as well as RPM (better than just HP/Liter).
(HP * 894.84) / (liters * rpm @ peak HP)
Here are some calculations of common Tercel engines, and similar car's engines:
Engine
BMEP
3E
7.99
3E-E
9.69
1st Gen 4E-FE
10.08
2nd Gen 4E-FE
10.39
4E-FTE
14.18
1st Gen 5E-FE
9.34
2nd Gen 5E-FE
10.41
5E-FHE
10.27
1NZ-FE
10.26
4A-GE
10.59
4A-GZE
14.54
4A-GE 20V
11.93
1ZZ-FE
10.69
Horsepower
Your basic calculation for horsepower. Everyone who tinkers with engines should know this one.
RPM x Torque / 5252 = Horsepower
Injector Horsepower Capacity
Calculations for estimating horsepower and injector size.
Horsepower limit of injectors = (Injector flow rate / 10.5) * Max Injector Duty Cycle / Brake Specific Fuel Consumption * Number of Cylinders
Ideal injector size (cc/min) = (Maximum Horsepower * Brake Specific Fuel Consumption) * 10.5 / (Number of Injectors * Maximum Duty Cycle)
Optimum Muffler Flow Rate
The ideal flow rate for your muffler. Too small and it will cause restriction and thus power loss.
Ideal muffler flow rate (CFM) = HP X 2.2
Suspension
Springrate
A rough calculation of spring rate.
Spring Rate (Lbs/In) = 11,250,000 * Bar Diameter ^ 4 / 8 * Number of active coils ^ 3
Bar & Tube Stiffness
A calculation to measure the stiffness of a bar. Very useful for increasing sizes of sway bars or any type of support bars.
Diameter ^ 4 = Stiffness
If you have a hollow tube, first calculate the outside diameter stiffness. Then, calculate the hollow diameter as if it were solid. Now subtract the first calculation from the second.