1. What is Camshaft Duration?

Camshaft duration refers to the length of time (measured in degrees of crankshaft rotation) that the valves remain open. It's a critical factor in engine performance, affecting power band, torque characteristics, and overall engine behavior.

2. How Does the Calculator Work?

The calculator uses a simplified formula to estimate camshaft duration:

Where:

• \( RPM\ Range \) — The desired engine operating range in RPM
• \( Lift \) — Valve lift in inches

Explanation: This formula provides a basic estimation of camshaft duration requirements based on your engine's intended RPM range and valve lift characteristics.

3. Importance of Proper Camshaft Selection

Details: Choosing the right camshaft is crucial for optimizing engine performance. The correct duration affects volumetric efficiency, power band, torque curve, and overall drivability of the vehicle.

4. Using the Calculator

Tips: Enter your target RPM range and desired valve lift. The calculator will provide an estimated duration recommendation. Consult with a professional engine builder for final camshaft selection.

5. Frequently Asked Questions (FAQ)

Q1: What's the relationship between duration and RPM?
A: Generally, higher RPM engines require longer duration camshafts to allow more time for air/fuel mixture exchange at higher speeds.

Q2: How does valve lift affect camshaft selection?
A: Increased valve lift typically works in conjunction with duration to improve airflow. Higher lift may allow for slightly less duration to achieve similar performance.

Q3: What other factors should I consider when choosing a camshaft?
A: Consider engine displacement, compression ratio, induction system, exhaust system, vehicle weight, gearing, and intended use (street, strip, or track).

Q4: What's the difference between advertised duration and duration at 0.050"?
A: Advertised duration is measured from the beginning of valve movement, while duration at 0.050" is measured from when the valve has lifted 0.050" off the seat, providing a more standardized comparison.

Q5: Should I choose a camshaft with more overlap?
A: Overlap (when both intake and exhaust valves are open) improves high-RPM performance but can reduce low-end torque and idle quality. The right amount depends on your specific application.