Cam Characteristics
Thread Starter
Drifting
Joined: Dec 2006
Posts: 1,359
Likes: 1
From: N.GA
Cam Characteristics
Alright, I need to know, what about the cam makes it lope like a bi***?
I know what the duration and lift numbers mean. I need to know what the lobe seperation angle is. What that means. And I really want to know what makes it lope real good. Thanks guys!!
I know what the duration and lift numbers mean. I need to know what the lobe seperation angle is. What that means. And I really want to know what makes it lope real good. Thanks guys!!
Safety Car
Joined: Jan 2004
Posts: 3,786
Likes: 1
From: Houston TX
Lope is causing by a valve event called overlap.
Info from LS1tech.com
Lobe Separation Angle (LSA)
- LSA is defined as spread in camshaft degrees between the intake centerline and the exhaust centerline.
- Overlap is the number of crankshaft degrees that both the intake and exhaust valves are open as the cylinder transitions through the end of the exhaust stroke and into the intake stroke
- LSA is ground into the cam and cannot be changed without grinding a new cam
- Bigger duration cams will have more overlap then a smaller duration cam even if both are on the same LSA.
- The key to making overlap work is maximizing the power in the rpm band where you want it.
- Long overlap periods work best for high-rpm power. For the street, a long overlap period combined with long-duration profiles combine to kill low-speed torque
- Reducing overlap on a long-duration cam will often increase midrange torque at the expense of peak power, but if the average torque improves, that’s probably a change worth making.
- Many enthusiasts purchase a camshaft strictly on the basis of how it sounds. A cam with generous overlap creates that distinctive choppy idle that just sounds cool.
- What really affects where the cam makes the most power is the intake timing events. What affects drivability most is the exhaust-closing event.
Info from LS1tech.com
Lobe Separation Angle (LSA)
- LSA is defined as spread in camshaft degrees between the intake centerline and the exhaust centerline.
- Overlap is the number of crankshaft degrees that both the intake and exhaust valves are open as the cylinder transitions through the end of the exhaust stroke and into the intake stroke
- LSA is ground into the cam and cannot be changed without grinding a new cam
- Bigger duration cams will have more overlap then a smaller duration cam even if both are on the same LSA.
- The key to making overlap work is maximizing the power in the rpm band where you want it.
- Long overlap periods work best for high-rpm power. For the street, a long overlap period combined with long-duration profiles combine to kill low-speed torque
- Reducing overlap on a long-duration cam will often increase midrange torque at the expense of peak power, but if the average torque improves, that’s probably a change worth making.
- Many enthusiasts purchase a camshaft strictly on the basis of how it sounds. A cam with generous overlap creates that distinctive choppy idle that just sounds cool.
- What really affects where the cam makes the most power is the intake timing events. What affects drivability most is the exhaust-closing event.
