ok, i dont know allot about turbos but what do waste gates and blow off valves to?
and why dont you need them on superchargers?

 

any body?

 

5 second search @ google.com "how does a turbo work"

http://www.turbotechnics.com/turbo/turbowork.htm

http://www.howstuffworks.com/turbo.htm

liam

 

wastegate regulates the boost pressure by regulating the exhaust gasses at the manifold. Blow off valve relieves boost after the throttle body is closed so it does not go back into the turbo(surge)

hope these quick simple explanations help. I am sure more people can give better technical explanations.

 

actually that sums it all up. no you do not need them on a supercharger,.

 

a blow off vlave releases the compressed air from the turbo when the throttle is closed, so the air doesn't back track to the turbo. it is usually located on the charge pipe from the intercooler to the throttle body but you will also see some located on the intercooler

a wastegate regulates the amount of boost. for example, if you are set at 5 psi, the wastegate will release exhaust gases when it reads 5 psi. if you had no wastegate your turbo would just run at maximum boost.
there are two kinds of wastegates: internal and external. the external one is usually located on the turbo manifold and has a dump tube attached to it so it can release the exhaust gases. the dump tube can be connected to the downpipe (usual rule of thumb is 18 inches after the turbo i believe) or it can just be released into the atmosphere like a blow-off vlave.
the internal wastegate is located on the turbo itself and is controlled by an actuator that opens and closes a flapper on the turbine outlet.

edit: i hope i explained this right