What you are talking about Chode is efficiency loss from excessive camshaft overlap.
The point (more specifically the duration) at which the intake & exhaust cam overlap and the pressurized air flows right through the cylinder and out the exhaust port.
Excessive overlap is not a good thing but some overlap is not bad to make the car more streetable and it will produce a better overall power curve.
Also the valve timing points play a role as well. A turbo camshaft would want the intake valve to open closer to TDC then an NA cam.
Some drag turbo engines even open them at or after TDC and also even run negative overlap.
Either of those conditions would make for a piss poor street car though as off and light boost power would plummet dramatically. As would your overall power curve. I just stated them as a point of reference.
