Originally Posted by
Lookin2GoFA$T
The exception to this rule is when we add nitrous, a turbocharger, or a supercharger. Intermediate overlap, short duration cams are chosen to prevent the boost from shooting into the exhaust manifold with a long cam overlap.
...change the LSA of the cam(s) and you will decrease the valve overlap. the bigger the duration, the higher in the RPM you will make power, and the more power you will make given that you have a head/intake that will compliment the airflow abilities of the cam(s)
However, with more intake cam duration there is a greater chance of cylinder pressure being lost out of the opening intake valve. We lose dynamic compression . Along with High Piston Speeds Away From TDC, big overlap cams will reduce cylinder pressures and prevent efficient burning or combustion of the air fuel mix.
that isn't necessarily true. its a give/take relationship. for the efficiency lost in the lower RPMs, efficiency is gained in the upper RPMs. and while im vaguely inclined to agree with most of this statement, im going to have to drag you along with me cause its about to be picked apart with a fine tooth comb. DCR is directly dictated by the valve event of the intake opening in correlation to the piston BTDC. the more degrees BTDC that the intake valve begins to open, the lower the DCR will be. but you can always alter at what degree the intake valve opens. and the DCR is always ever-changing, cause damn near everything effects it.
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El Pendejo Loco
2002 Suzuki Hayabusa
1507 "dry" block
Brocks megaphone
Spencercycle 10" swingarm
MPS auto shifter
Hays convertible clutch
Yea, that about sums it up...
