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Author Topic:   Cam Characteristics
posted November 20, 2003 09:17 AM
Generally more duration moves the power band up in the rpm range. Example: Street cars that have an rpm range of idle-4000 use around 200 degrees duration @.050" Race cars that run around 5000-7000 may use around 250 degrees duration. More duration isnt necessarily more power... it depends on the rest of your combo, compression, ariflow, gearig etc.
Intake duration @ .050 is the duration in degrees of rotation between when the lifter is first raised .050" by the cam and when it is .050 from being seated again. Advertised duration is typically the same only at .006 or .020 lifter rise. It will always be longer than the .050 numbers.
If that cam is really 282/290 @ .050 then it would be suited for an application where there needs to be power very high in rpm range. Like 9000-10000 rpm.

posted November 20, 2003 02:26 PM
What dirtbuster said.

It's also impossible to compare the advertised duration of a cam from 2 different companies. Some use .004" (makes it sound bigger, some use .006" and some use .020". The .050" is by far the most important.

Lift generally doesn't affect powerband much. But, a .400" lift cam will make less power than a .500" cam with the same duration. In 99% of the case, the higher the lift the better. Usually the limiting factor of lift is valve springs and retainer to guide clearance issue. Stock heads flow best up to .500" and may actually flow less above .550".

dan ferry
posted November 20, 2003 08:04 PM
look on crower cams or isky 's websitesthey have sections that explain this and more helps understand go under degreeing a cam it will help under stand alot.

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