cam duration
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cam duration this might be a stupid question but does more cam duration help or hurt you on the top end (rpm wise). i know more lift helps you, but i dont know about duration.
Lift helps you so as long as your heads are breathing there. If you have a .600" lift cam and your peak CFM was at .500" then it's a waste and you'd better off to save your valve springs. Duration is how long the valves are open in crankshaft degrees. Generally the more intake duration there is, the higher your power band becomes and you gradually lose power on the low end. There are complementary mods that should be made like gearing. You want a lower gear with a big cam to reach and stay in your powerband. Big cams aren't really for the street cuz your low end torque is down and you've got a dog that isn't fun to drive.
Thread Starter
TECH Resident
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Joined: Oct 2006
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From: Charleston, West Virginia
ok thanks. i knew what duration was but i just didnt know if it was benificial in the top end or low end. to tell you the truth, the cam im lookin at isnt even for an LT1, its for my dirtbike. im lookin at a bigger cam thats got a lot more duration than the stock cam, but only about .5 mm more lift. i am trying to get more top end power (big bore, big carb, stiffer valve springs) and i was wondering if the duration was gonna help or hurt me. thanks
