Lobe Seperation Angle question
Lobe Seperation Angle question ok have a question about LSA and its effect on boost (supercharger). Alot of people are telling me that if a cam has a lower LSA like a 112 or lower it would not make for a good blower cam because you would lose boost...can someone explain to me how that is? sorry for the stupid question but i am learning as i go 
The lower LSA causes more over lap (the amount of time the intake and exhaust valves are open at the same time). This is good for a naturally aspirated motor because it causes a scaviging effect and helps pull more fuel and air into the combution chamber. On a blown motor you don't need or want that! the intake is under presure and forces the air into the combution chamber. If both are open then you will let more unburnt fuel and air escape without getting used, and also bleeding off your cylinder presure to. It is possible to run these LSA's but not the best conditions for tuning and power. There is a guy I think it is HUGGER ORANGES SS that is puting down 600 rwhp with a hot cam but he admits it's not ideal. Hope that help and I hope I was not to far off on explaining it.
Inspector12 nailed it.
You end up with a less than optimal setup for a supercharged setup since the intake and exhaust valves are open at the same time, for too long, you end put pushing boost right out the exhaust valve.
You end up with a less than optimal setup for a supercharged setup since the intake and exhaust valves are open at the same time, for too long, you end put pushing boost right out the exhaust valve.
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scavenging is commonly used on heads that underflow at high rpms with blower cars. They are terrible for turbos (lag) but indeed work with a blower, when the HEADS are not flowing to their peak potential.
Fortunately we all have great flowing heads right
Fortunately we all have great flowing heads right
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