Horsepower Calculator Bore Stroke Compression

Horsepower Formula:

\[ HP_{bsc} = \frac{Disp \times RPM \times CR \times VE}{BSFC \times 792000} \]

Bore:

inches

Stroke:

inches

Number of Cylinders:

RPM:

Compression Ratio (CR):

Volumetric Efficiency (VE):

BSFC:

lb/HP-hr

Calculated Horsepower (HP):

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1. What is the Horsepower Formula?

The horsepower formula calculates engine power output based on displacement, RPM, compression ratio, volumetric efficiency, and brake specific fuel consumption. It provides an estimate of an engine's potential power output.

2. How Does the Calculator Work?

The calculator uses the formula:

\[ HP_{bsc} = \frac{Disp \times RPM \times CR \times VE}{BSFC \times 792000} \]

Where:

\( Disp \) — Engine displacement (cubic inches)
\( RPM \) — Engine speed (revolutions per minute)
\( CR \) — Compression ratio
\( VE \) — Volumetric efficiency (%)
\( BSFC \) — Brake specific fuel consumption (lb/HP-hr)

Explanation: The formula calculates how much air an engine can move and how efficiently it converts that air flow into power.

3. Importance of Horsepower Calculation

Details: Accurate horsepower estimation is crucial for engine design, performance tuning, and comparing different engine configurations. It helps engineers and enthusiasts understand an engine's potential performance.

4. Using the Calculator

Tips: Enter bore and stroke in inches, number of cylinders, RPM, compression ratio, volumetric efficiency as a percentage, and BSFC. Typical BSFC values range from 0.38-0.50 lb/HP-hr for most engines.

5. Frequently Asked Questions (FAQ)

Q1: What is volumetric efficiency?
A: Volumetric efficiency measures how effectively an engine can move air into and out of the cylinders. Most production engines have VE between 75-90%.

Q2: What is a typical BSFC value?
A: Brake specific fuel consumption typically ranges from 0.38 for highly efficient engines to 0.50 for less efficient designs. 0.45 is a common default value.

Q3: How is displacement calculated?
A: Displacement = π × (bore/2)² × stroke × number of cylinders

Q4: Why is compression ratio important?
A: Higher compression ratios generally produce more power but may require higher octane fuel to prevent knocking.

Q5: How accurate is this calculation?
A: This provides a theoretical estimate. Actual horsepower can vary based on many factors including intake/exhaust design, ignition timing, and fuel quality.