Does a bigger cam increase compression?
Overlap causes a “scavenging effect” as the engine RPM increases. This is why performance cams “come alive” at higher RPMs. It’s not “just” the cam making the power, it’s the cam’s scavenging effect working as the RPM increases which increases cylinder pressure (dynamic or effective compression).
How does cam profile affect performance?
Designing a cam profile with more lift results in increased duration in the high-lift regions where cylinder heads flow the most air. Short duration cams with relatively high valve lift can provide excellent responsiveness, great torque, and good power. But high lift cams are less dependable.
How is intake duration determined in a camshaft?
The first two events determine the intake duration (closing minus opening), which is built into the camshaft. The exhaust opening and closing are the next most important parameters. The exhaust lobe is fixed relative to the intake lobe by the lobe separation angle.
How does a high performance camshaft gain power?
In order to gain power with a high performance (longer duration) camshaft, you must have an engine which is capable of reaching the higher RPM levels. For example, no matter how much duration you have, a stock Model T motor is never going to turn 5,000 RPMs.
Which is the best type of camshaft for a supercharged engine?
“Duration at .050” lift” is the deciding factor to what the engine’s basic rpm range will be. Lower duration cams produce the power in the lower rpm range. Larger duration cams operate at higher rpm, but lose bottom-end power. Which type of camshaft is best for a supercharged engine?
How is the torque of a camshaft determined?
It is determined by a combination of camshaft lobe lift and rocker arm ratio. The amount of valve lift you have and the speed at which the valve moves is a key factor in determining how much torque the engine will produce.
Is the intake and exhaust of a camshaft the same?
If you’ve ever looked at a cam card (furnished with each new camshaft), you’ve probably noticed that some cams have the same specs for both the intake and exhaust (single pattern), while others differ (dual pattern).
What happens when you increase the duration of a camshaft?
When you increase the duration of a given camshaft, you shift the power and torque curves upward in the rpm range. For that reason, longer duration camshafts are suited for higher rpm operation.
Why does a camshaft increase the power band?
This explains why an increase in the intake valve duration moves the power band to higher engine speeds. When the cam is advanced, the intake valve closes sooner, so you get more power at the low end. Reducing the lobe separation angle also causes the intake valve to close sooner, so you again get more low end power.
What’s the length of a camshaft on a Chevy?
As an example, Howards Cams’ small-block hydraulic flat-tappet Max Torque camshaft (PN 112021) Chevy measures 222/232-degree duration on the intake and exhaust, respectively at 0.050-inch lobe lift, whereas the advertised duration is 288/302 degrees. Generally, added duration is helpful in high-rpm engines, but not typically in low-rpm engines.