General Category > Quadrajet Carb Talk and Tips

camshaft rules of thumb?

<< < (3/3)

Shark Racer:
At a basic level, increasing duration shifts the power band of a cam upwards and makes it run "worse" at lower RPM. This is due to reversion. More duration = more likelihood of overlap = more reversion.

The tighter LSAs also increase overlap, as LSA is a measurement of the angle in degrees between peak lift on exhaust and intake lobes.  Thus a tighter LSA hints at more overlap and a looser LSA less. Overlap is what kills idle as it becomes difficult to get a consistent vacuum signal. This is why people have to run higher idles - to get a better, more consistent vacuum signal.

PHR has a decent article here: http://www.popularhotrodding.com/enginemasters/articles/hardcore/0606em_camshaft_specs/viewall.html

Navigation

[0] Message Index

[*] Previous page