Horsepower & Torque
HP = Torque x RPM / 5252
TQ = Horsepower x 5252 /RPM 
Engine Displacement
Displacement = #cyl x Swept Volume
Displacement is in CC's 
Example: What torque is required to generate 300hp at 6,200RPM?
TQ = 300 x 5252 / 6200 = 254ft/lbs of torque @ 6,200RPM 
Example: 4G93 1.8 liter engine
4cylinders, 81mm bore and 89mm stroke
Disp = 4 x 0.7854 x 81 x 81 x 89 / 1000 = 1834.5cc 
Displacement Conversions
Cubic Inches of Displacement to Cubic Centimeters
CID = CC / 16.39
CC = CID x 16.39 
Choosing Fuel Injectors
Finding injector size required for a certain HP amount (total engine output)
LBS/HR =( [BSFC / (# cyl)] x HP) / Peak Injector Duty Cycle 
Example: Cubic Inches of Displacement for a 1834.5cc engine
CID = 1834.5 / 16.39 = 111.9 
Example: BSFC = .50, Duty Cycle = 80%, HP target = 200
LBS/HR (per injector) = (.125 x 200) / .8 = 31.25 
Fuel Injectors
BSFC = Brake Specific Fuel Consumption. The ratio of fuel consumed (in pounds per hour) to horsepower produced. Simply how efficient the engine is at converting the fuel into power.
Typical BSFC values:
lower values = more efficient
NA = .50  .55
Turbo = .55  .60
Methanol = double the previous values
Max HP of injectors (lbs/hr) on gasoline
HP = ([Injector Size (lbs/hr) x Duty Cycle] / BSFC) x # of injectors) 
Fuel Conversions
CC/Minute to LBS/Hour
LBS/Hr = CC / 10.5
CC/Min = LBS x 10.5
LBS/Hour to Gallons/Hour
GPH = LBS / 6
LBS = GPH x 6
CC/Minute to Gallons/Hour
GPH = CC x .01585
CC = GPH / .01585
Fuel Pump Flow Conversion
LBS/HR to Gallons/Minute
GPM = LBS/HR / 360 
Example: HP rating of each injector on a 4cylinder engine. 19LBS/HR injectors @ 80% Duty Cycle and .50 BSFC
HP per inj. = [(19 x .80) / .5] x 4 = 121.6 
Example: LBS/Hr flow rate for a 210cc/min fuel injector
LBS = 210 / 10.5 = 20 
Miles to Kilometers Conversion
To convert miles to kilometers, multiply the miles value by 1.61.
Kilometers = miles × 1.61

Kilometers to Miles Conversion
To convert kilometers to miles, divide the kilometers value by 1.61.
Miles = kilometers / 1.61

Example: How fast is 60mph in kph?
KPH = 60mph x 1.61 = 96.6kph
Example: How far is 60 miles in kilometers?
Kilometers = 60 miles x 1.61 = 96.6 kilometers 
Example: How fast is 80kph in mph?
MPH = 80kph / 1.61 = 49.69mph
Example: How far is 80 kilometers in miles?
Miles = 80 kilometers / 1.61 = 49.69 miles 
Kilowatt to Horsepower Conversion
To convert kilowatt to horsepower, multiply the Kw by 1.34102209.
Horsepower = kilowatt × 1.34102209Hp

Horsepower to Kilowatt Conversion
To convert horsepower to kilowatt, divide the horsepower value by 1.34102209.
Kilowatt = horsepower / 1.34102209Kw

Example: How many horsepower is 130Kw?
Hp = 130Kw x 1.34102209 = 174.33Hp 
Example: How many kilowatts is 200Hp?
Kw = 200Hp / 1.34102209 = 149.14Kw
