The idea of long duration is to an extent overcome exhaust back pressure - they work well with restrictive turbo's - allow them to rev more as u are keeping the exhaust valve open for longer allowing the gases to do one. Problem is, at low rpm. the gas is moving slowly - it's coming in through the inlet valve and going straight out the still open exhaust valve without getting combusted. Thats why u get lumpy idles and poor low down torque. Would be really nice to implement a VTEC system on a binliner/YB