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*Note: Some of these definitions in which I understand but can not word to make you understand will be taken word for word out of the Lincoln Tech Automotive Division Automotive Technology text book. In which I have the right to use because I paid 23k for one year of school.*

**- A force that tends to rotate or turn things and is measured by the force applied and the distance traveled. The technically correct unit of measurement for torque is pounds per foot (lb-ft). An engine creates torque and uses it to rotate the crankshaft. The combustion of gasoline and air in the cylinder creates pressure against the top of a piston. That pressure creates a force on the piston and pushes it down. The force is transmitted from the piston to the connecting rod and from the connecting rod to the crankshaft. The engines crankshaft rotates with a torque that is transmitted through the drivetrain to turn the drive wheels of the vehicle.**

__Torque____- When gears with different numbers of teeth mesh, each rotates at a different speed and force. Torque is calculated by multiplying the force by the distance from the center of the shaft to the point where the force is exerted.__

**Torque Multiplication**__- Is a measurement for the rate, or speed, at which work is done__

**Power****- A rate at which torque is produced.**

__Horsepower__- Example-An engine that produces 300 pound-feet of torque at 4,000 rpm produces 228 horsepower at 4,000 rpm. This is based on the formula that horsepower is equal to torque multiplied by engine speed and that sum divided by 5,252. The constant, 5,252, is used to convert the rpm for torque and horsepower into rpm's.

__- Based upon a lot of things, base horsepower, the loss of horsepower between moving parts, temperature, humidity, operation, dyno, altitude and other variables. That's why it is important to compare your own dynos to yourself. To not be discouraged if someone else got a higher wheel horsepower and you have more mods. Dynos should be used for your personal use in advancement through mods.__

**Wheel Horsepower**__- Is a measurement of size and is related to mass and weight. Volume is the amount of space occupied by an object in three dimensions: Length, width, and height.__

**Volume**__- Is the volume of a cylinder between when the cylinders piston is at its lowest point of travel (BDC, Bottom Dead Center), and its highest point of travel (TDC, Top Dead Center). Displacement is usually measured in cubic inches, cubic centimeters, or liters.__

**Displacement**__- The sum of displacements for all cylinders in an engine. The total displacement of an engine (including all cylinders) is a rough indicator of its power output.__

**Total Displacement****CID**(Cubic Inch Displacement)=**Pi**(3.1416)x**R^2**(radius squared)x**L**(length of stroke)x**N**(number of cylinders)

__- Express' how much an engines air/fuel mixture will be compressed as the piston in a cylinder moves from BDC to TDC of the cylinder.__

**Compression Ratio**__- A toothed wheel that becomes a machine when it is meshed with another gear. Gears apply torque to other rotating parts of the drivetrain and are used to multiply torque.__

**Gear**__- An expression of gear size and tooth count of gears that are meshed together. The ratio reflects torque multiplication. To calculate a gear ratio, divide driven (output) by the drive (input).__

**Gear Ratio**__- A push or pull and can be very large or very small.__

**Force**__- Is a force applied against an object and is measured in units of force per unit of surface area (PSI).__

**Pressure**__- Is the distance an object travels in a set amount of time__

**Speed**__- A force that slows or prevents motion in two moving objects or surfaces that touch.__

**Friction**__- Is the movement or flow of electricity. Current is measured in Amps.__

**Current**__- Is electrical pressure. Voltage is measure in Volts.__

**Voltage**__- Resistance is measure in Ohms__

**Resistance**__- V/AxR__

**Ohms Law****- Take the first measurement then multiply it by the number next to it to get the measurement in the middle. Or you can reverse the problem if you have the oppistite measurement you want then multiply the number in the middle to the number next to it to get the measurement you understand.**

__Metric/USC Conversions__Example- Converting Foot-pounds to Newton-meters

2 Foot-pounds x 1.3558=2.7116 Newton-meters

2 Newton-meters x .7376= 1.4752 Foot-pounds

- Foot-pounds x 1.3558 = Newton-meters x .7376 = Foot-pounds
- Horsepower x .7457 = Kilowatts x 1.341 = Horsepower
- Inches x 25.4 = Millimeters x .03937 = Inches
- Cubic Inches x .01639 = Liters x 61.024 = Cubic Inches
- Pounds x .454 = Kilograms x 2.205 = Pounds
- Miles Per Hour x 1.609 = Kilometers Per Hour x .6214 = MPH
- Pounds Per Square Inch x .069 = Bar x 14.50 = PSI
- Pounds Per Square Inch x 3.895 = kPa x .14503 = PSI
- Fahrenheit-32 and then /1.8= Celsius x 1.8 + 32 = F