Originally Posted by msheredy
This is exactly what I mean. You have never been more incorrect. Obviously you have never swapped cams in a car. When you put a high performance cam in the inherit nature is a lopier idle. Ask
ANY engine builder.
Supercharged cars aren't supposed to have a lopey idle? You need to go to the drags or classic car show!
http://www.youtube.com/watch?v=6JKJXWO6yF8
we are not talking about drag cars, this is a street car.
from what I understand it's the lobe overlapp time which dictates if a cam is going to have a lopey idle.
And our NA cams are more agressive when compared to boost cams, because the NA cam is using the scavenging effect to increase cylinder fill of the air/fuel mix, by allowing the exhaust gasses to pull a low pressure point on the cylinder. This increases the velocity of the incoming air into the cylinder. much like a two stroke motor.
On a boost cam, it has less overlap version than the NA cam because, the super charger is feeding the cylinder it's air/fuel mix, so there is no need to have a the cam which creates the scavenging effect.
now if you put the NA cam in the superchaged engine, you will be loosing cylinder pressure because of the overlap of the NA cam with leave the exhaust valve open, thus letting the undurned pressurize air/fuel mix to blow out the exhaust manifolds.
NOw why does my N/A M112 motor, idle smooth as silk at 500rpm, while this guys SC m112 sound so lopy at 500rpm? Maybe he has a vacuum leak.? because I know the boost cam will not creat a lopy effect, the schricks cams do have more lift, but they are a custom grind and are not listed in their catalouge, which also makes me wonder about the design or if this guy has the correct cams installed.