bro..from what i've known knife edging of the crankshaft is for lightening purposes and also less windage losses..means that bcoz of we are using wet sump configuration so there will be oil in the sump most of the time unlike dry sump..so they usually knife edged it to make it cut through the oil like knife thru butter..hehe sorta..but downside is other than what the sifus has highlighted, there are also problems of harmonics at high engine speeds..it wud bcome unbalance then the crank might take a "walk" hehe..that's why some tuners like AEBS prefers to have full counter weight just like in F1..just sharing what i've heard..feel free to comment..
the thread is mainly about knife edging,which in a way brings to some sort of trimmings that causes lightening.for turbo applications,u dont actually need heavy conrod and cranks,just solid ones.now u can find billet cranks and rods as an upgrade to forged materials.billet still light but can withstand higher boost and abuse.just my 2cents.
