Does a Camshaft Add Horsepower? Unveiling the Impact on Engine Performance

A camshaft is a critical component in an internal combustion engine, responsible for controlling the opening and closing of the engine’s valves. By carefully manipulating the camshaft’s design, it is possible to significantly impact the engine’s power output, efficiency, and overall performance. In this comprehensive guide, we will delve into the intricacies of how a camshaft can add horsepower and unveil the profound impact it has on engine performance.

Understanding Camshaft Lift, Duration, and Overlap

The three primary characteristics of a camshaft that influence engine performance are lift, duration, and overlap.

Camshaft Lift

Camshaft lift refers to the maximum distance the valve is lifted from its seat. A higher lift allows for a greater volume of air and fuel to enter the cylinder, which can result in increased power output. However, excessive lift can lead to a phenomenon called “valve float,” where the valve’s mass and speed cause it to bounce off the cam lobe, leading to decreased performance and potential engine damage.

Typical camshaft lift ranges from 0.400 inches to 0.600 inches for street-driven engines, while high-performance engines can have lift values exceeding 0.700 inches. For example, a high-performance camshaft in a Ford Mustang 5.0L V8 engine may have a lift of 0.550 inches on the intake valves and 0.540 inches on the exhaust valves, providing a significant boost in power compared to the stock camshaft.

Camshaft Duration

Camshaft duration refers to the amount of time the valve is held open during the engine’s cycle. A longer duration allows for more air and fuel to enter the cylinder, which can increase power output. However, an excessively long duration can lead to decreased low-end torque and increased emissions.

Typical camshaft duration ranges from 220 degrees to 260 degrees for street-driven engines, while high-performance engines can have duration values exceeding 280 degrees. For instance, a high-performance camshaft in a Chevrolet Corvette 6.2L V8 engine may have a duration of 248 degrees on the intake valves and 254 degrees on the exhaust valves, providing a noticeable increase in power across the engine’s rev range.

Camshaft Overlap

Camshaft overlap is the amount of time both the intake and exhaust valves are open simultaneously. Increasing overlap can improve volumetric efficiency by allowing exhaust gases to exit the cylinder more quickly, which in turn allows for more fresh air and fuel to enter.

Typical camshaft overlap ranges from 40 degrees to 60 degrees for street-driven engines, while high-performance engines can have overlap values exceeding 70 degrees. For example, a high-performance camshaft in a Dodge Challenger 6.4L V8 engine may have an overlap of 58 degrees, providing a noticeable improvement in power delivery and engine responsiveness.

The Impact of Camshaft Degreeing

Camshaft degreeing is the process of precisely aligning the camshaft with the crankshaft to ensure optimal performance. This process involves measuring the intake centerline, which is the point at which the intake valve opens and closes relative to the crankshaft’s position.

Proper camshaft degreeing can result in the following benefits:

• Increased power output: By aligning the camshaft with the crankshaft, the engine can more efficiently utilize the air and fuel mixture, leading to increased power output.
• Improved reliability: Correctly degreeing the camshaft can reduce stress on the engine components, improving overall reliability and longevity.
• Longer engine life: Proper camshaft degreeing can help prevent premature wear and tear on the engine’s internal components, extending the engine’s lifespan.

For example, a properly degreeed camshaft in a Subaru WRX 2.4L turbocharged engine can increase power output by up to 15 horsepower and 20 lb-ft of torque, while also improving engine responsiveness and reducing the risk of premature component failure.

Choosing the Right Camshaft for Your Engine

When selecting a camshaft for your engine, it’s essential to consider factors such as the engine’s displacement, compression ratio, and intended use (e.g., street, track, or drag racing). Consulting with a professional engine builder or camshaft manufacturer can help you choose the optimal camshaft for your specific application.

For instance, a street-driven Ford Mustang 5.0L V8 engine may benefit from a camshaft with a lift of 0.500 inches, duration of 230 degrees, and overlap of 50 degrees, providing a balance of power, drivability, and emissions compliance. In contrast, a high-performance Ford Mustang 5.0L V8 engine built for track use may require a camshaft with a lift of 0.550 inches, duration of 250 degrees, and overlap of 60 degrees, prioritizing power output over low-end torque and emissions.

Conclusion

In conclusion, a camshaft can have a profound impact on an engine’s performance by controlling the opening and closing of the valves. By carefully manipulating the camshaft’s lift, duration, and overlap, it is possible to significantly increase horsepower and torque. Additionally, proper camshaft degreeing is crucial to ensure optimal engine performance, reliability, and longevity. When selecting a camshaft for your engine, it’s essential to consider the specific requirements of your application to achieve the desired power and drivability characteristics.

Reference:
– Reddit Discussion on Aftermarket Camshafts
– Secrets of Camshaft Power
– Camshaft Class: Back in Session
– Camshaft Degreeing: To What Degree Do You Want to Win?
– Choosing the Right Camshaft for Your Performance Engine