Why use extended duration cam
04-25-2010, 01:55 PM
#1
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Why use extended duration cam Looking to purchase a race kit for my bike and most of the kit has items to increase CR and reduce squish height and PV clearance but then goes about including revised intake and exhaust cams with extended duration b/c increased lift would become a PV problem right... but from my understanding extended duration will take away from your DCR or reduce it. So wouldn't this be counter productive?
04-25-2010, 05:51 PM
#2
DCR is just a sanity check to make sure you are in the ball park for the type of fuel you are running. You need the right amount of duration to increase cylinder fill. Keep in mind you now have extra air / fuel in the cylinder so you will needed increased exhaust duration to evacuate the burned charge. The added duration will allow a higher volume of air / fuel to enter the cylinder thus creating more power. Just increasing your DCR from raising static compression will help with hp / torque and throttle response, but as they say it takes more fuel / air to make power.
