Calculators
Interactive motorcycle and drag racing calculators by Liguori Drag Racing.
Engine Calculators
Piston Speed Calculator
Compare mean piston speed for your current and proposed stroke at the same engine RPM.
Ring Gap Calculator
Calculate top- and second-ring gaps from bore and your ring-kit factors, with optional measured-gap comparisons. Opens in US Standard.
Compression Ratio Calculator
Calculate static compression ratio from bore, stroke, chamber, piston, compressed gasket and deck clearance. Opens in US Standard.
Engine Displacement Calculator
Calculate engine size from bore, stroke, and cylinder count. Opens in metric and shows cc, liters, and cubic inches.
Fuel System Calculators
Injector Change Fuel Table Calculator
Compare old and new injector flow to calculate the fuel-table multiplier, percentage increase or reduction, and an example injection-time value.
Fuel Needed per Pass Calculator
Plan fuel for the run, staging, and return trip, then add your chosen reserve for multiple passes.
Fuel Injector Calculator
Estimate injector size using target crankshaft power, fuel, induction type, and duty cycle. Opens in US Standard with horsepower and lb/hr.
Fuel Pump Calculator
Estimate required pump flow at operating pressure, including boost reference, extra capacity, and optional line losses. Opens in US Standard with horsepower, PSI, and US gal/hr.
Track Calculators
Bracket Racing Finish-Line Calculator
Compare dial-ins, reaction times, elapsed times, and finish speeds to review the finish line and breakout margins.
Drivetrain Calculators
Chain Size & Gearing Calculator
Scale sprockets between common motorcycle chain sizes. Compare gearing ratios, sprocket diameters, and nearby tooth combinations.
Finish-Line RPM & Gearing Calculator
Compare engine RPM at your finish-line speed and road speed at a target RPM with current and proposed sprockets.
Chain Length Calculator
Adjust sprockets and center distance with live sliders and a sprocket diagram. Compare even chain link counts and axle positions. Opens in US Standard with inches and feet.
Motorcycle Chain-Drive Gear Ratio Calculator
Compare current and proposed sprocket sizes with live sliders and a sprocket diagram. See final-drive ratio, percentage changes, and nearby gearing combinations.
Metric options are available within each calculator. More custom calculators will be added here as our collection grows.
Conversions
Injector Flow Conversion
Convert injector flow between mass and volume units using your fuel’s density or specific gravity.
Pump Flow Conversion
Convert pump flow between US gallons, liters, and cubic centimeters per unit of time.
Pressure Conversion
Convert PSI, bar, kilopascals, megapascals, and other pressure units instantly.
Power Conversion
Convert mechanical horsepower, kilowatts, metric horsepower, and watts.
Injector Flow at Pressure
Estimate injector flow at a different differential pressure, with your choice of output units.
Weather Calculators
12 interactive tools, each with its own page. Opens in US Standard.
- Density Altitude
- Air Density
- Dew Point
- Vapor Pressure
- Grains of Water
- Dyno Correction Factors
- Barometer Correction
- Jetting Correction
- Weather Correction Horsepower
- Wind Chill & Heat Index
- Wet Bulb Temperature
- Air Density Index
Electrical Calculators
Race Bike Battery Capacity Calculator
Total electrical consumption for passes between charges. Enter average current and total on-time for each load in one pass cycle.
4 interactive tools, each with its own page. Opens in US Standard.
Forced Induction Calculators
15 interactive tools, each with its own page. Opens in US Standard.
- Turbo Airflow Requirement
- Boost for Target Horsepower
- Compressor Map Operating Point
- Wastegate Area Comparison
- Turbo Compressor Sizing
- Compressor Efficiency
- Intercooler Efficiency
- Charge Air Temperature
- Intercooler Core Sizing
- Intercooler Pipe Diameter
- Supercharger Pulley Ratio & Boost
- Nitrous Oxide Horsepower Gain
- Nitrous Jet Sizing — NX Chart Lookup
- Blow-Off Valve Flow Area
- Boost By Gear
Suspension Calculators
Shock Spring Preload Calculator
Compare initial spring force and force after additional shock compression for two linear-rate spring setups.
Motorcycle Shock Spring Rate Calculator
Get a quick spring-rate starting reference using motorcycle model/year and suited rider weight. Add wheelbase, horsepower, power adder and tire details to a shock-builder summary. Detailed measurements are optional. Opens in US Standard.