EngineCalc vs AutoTech

EngineCalc is the essential toolkit for engine builders, mechanics, and motorsport enthusiasts. Whether you're building a street rod, a race engine, or modifying a performance vehicle, EngineCalc puts the math at your fingertips — with the formula shown for every calculation so you always understand exactly what's happening under the hood. CALCULATORS Piston • Piston Speed — mean piston velocity from RPM and stroke • Compression Ratio — from cylinder and chamber volumes • Rod Ratio — connecting rod length to stroke relationship • Rod Length — from block length, stroke, and deck clearance • Piston Dome Volume — dome cc needed to hit a target compression ratio • Compression Height — wristpin height from deck clearance and stroke • Cylinder Displacement — total displacement from bore, stroke, and cylinder count Power • Simple Horsepower — quick HP from RPM and torque • Torque — from horsepower and RPM • Horsepower — using MEP, displacement, compression ratio, and VE • Corrected BHP — sea-level horsepower adjusted for altitude • BHP Loss — how much power elevation costs you • Volumetric Efficiency — actual vs. theoretical airflow • Theoretical Volume Flow — maximum CFM at a given RPM • Actual Volume Flow — real-world CFM with volumetric efficiency Fuel • Air Density — available oxygen from altitude and temperature • Mass Flow — air mass moving through the engine per minute • BSFC — brake specific fuel consumption and engine efficiency UNIT CONVERSIONS Thirteen categories covering every unit an engine builder needs: Torque • Pressure • Power • Volume • Temperature • Length • Mass Speed • Force • Fuel Efficiency • Frequency • Energy • Angle Type a value in any unit and all others update instantly. Categories you use most rise to the top automatically. FEATURES • Search — jump straight to any calculator by name • Metric and Standard measurement systems — switch anytime, values convert automatically • Formulas displayed for every calculator — no black boxes • Results shown with units, and shareable to any app or message • Result history — your last stored values for each calculator • Built-in guide — contextual help for calculators and conversions, available anytime • Works completely offline — no account, no subscription, no data collected

AutoTech is an automotive calculator that offers the mechanic, technician or enthusiast quick computation of 45+ formulas in the areas of aerodynamics, chassis, drivetrain, engine, performance, suspension, and tires. Supports both U.S. and metric units.