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Lobe Separation Angle Formula:
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Lobe Separation Angle (LSA) is a camshaft specification that represents the angular distance between the centerlines of the intake and exhaust lobes. It's a critical parameter in engine design that affects engine performance characteristics including torque curve, power band, and idle quality.
The calculator uses the LSA formula:
Where:
Explanation: The LSA is simply the average of the intake and exhaust centerline angles, providing a single value that characterizes the camshaft's lobe positioning.
Details: LSA affects engine performance significantly. Narrow LSA (104-108°) typically produces more low-end torque and higher cylinder pressure but rougher idle. Wider LSA (112-116°) provides smoother idle, broader power band, and better high-RPM performance but less low-end torque.
Tips: Enter both intake and exhaust centerline values in degrees. The values should be positive numbers representing the angular measurements of your camshaft specifications.
Q1: What is a typical LSA range for performance cams?
A: Performance cams typically range from 106-114° LSA, with street performance cams often around 110-112° and race cams sometimes as narrow as 104-108°.
Q2: How does LSA affect engine sound?
A: Narrower LSA creates more overlap, resulting in the distinctive "lumpy" idle sound associated with performance cams, while wider LSA produces smoother idle.
Q3: Can LSA be changed on an existing camshaft?
A: No, LSA is a fixed specification determined during camshaft grinding. To change LSA, you need a different camshaft.
Q4: How does LSA relate to overlap?
A: While related, they're different measurements. Overlap is the duration when both valves are open, while LSA is the angular separation between lobe centers. Narrow LSA generally increases overlap.
Q5: What LSA is best for forced induction applications?
A: Forced induction engines often benefit from wider LSA (114-118°) to reduce overlap and prevent blowing pressurized intake charge directly out the exhaust.