Editing How to choose a camshaft (section)
Jump to:
navigation
,
search
===Lobe separation angle (LSA)=== The lobe separation angle, sometimes called lobe ''displacement'' angle, is a measurement in ''camshaft'' degrees that states how far apart the maximum lift points of the exhaust and intake lobes are. This number is ground into the cam and can't be altered without physically changing the camshaft lobe profiles. [[File:Las drawing.jpg|thumb|left|400px]] <br style="clear:both"/> A CHP magazine article comparing identical camshafts except for the LSA (along with comparing open vs. split plenum intakes): [http://www.chevyhiperformance.com/tech/engines_drivetrain/cams_heads_valvetrain/0905chp_camshaft_lobe_separation_angle_performance_test/viewall.html '''Camshaft Lobe Separation Angle Performance Test'''] ====Narrower LSA:==== A narrower LSA will ''increase'' overlap. This has a tendency to increase engine output at lower RPM and decrease engine output at higher RPM. A narrower LSA tend to make less peak power but more average power. *Moves torque to lower RPM *Increases maximum torque *Narrow power band *Builds higher cylinder pressure *Increase chance of engine knock *Increase cranking compression *Increase effective compression *Idle vacuum is reduced *Idle quality suffers *Valve overlap Increases *Natural EGR effect increases *Decreases piston-to-valve clearance ====Wider LSA:==== A wider LSA tend to make less peak power, but a broader powerband. Changing the LSA also changes the valve timing events; opening the exhaust valve sooner and closing the intake valve later, both of which affect how the engine ingests air. *Raise torque to higher RPM *Reduces maximum torque *Broadens power band *Reduce maximum cylinder pressure *Decrease chance of engine knock *Decrease cranking compression *Decrease effective compression *Idle vacuum is increased *Idle quality improves *Valve overlap decreases *Natural EGR effect is reduced *Increases piston-to-valve clearance
|
Editing help
(opens in new window)
Personal tools
Log in / create account
Namespaces
Page
Discussion
Variants
Views
Read
Edit
View history
Actions
Search
Navigation
Main Page
Recent changes
Random page
Help
All articles
Start a new article
Hotrodders forum
Categories
Best articles
Body and exterior
Brakes
Cooling
Electrical
Engine
Fasteners
Frame
Garage and shop
General hotrodding
Identification and decoding
Interior
Rearend
Safety
Steering
Suspension
Tires
Tools
Transmission
Troubleshooting
Wheels
Toolbox
What links here
Related changes
Special pages
Terms of Use
Copyright
Privacy Policy
Your Privacy Choices
Manage Consent