What is the difference on the two and what does a bleedvalve do by the way?
I know about the DV but not the BV

 

A Bleed Valve is one of the most basic forms of Boost Adjustment and generally costs around Ł15.

They are the cause of alot of failed engines, due to how easy it is wind the boost up and melt the engine.

They are quite good though if used correctly. The Alloy one's are a little unreliable though, due to the fact that they are affected by heat.

 

bleedvalve as above....

dumpvalve is a form of pressure release for turbo cars. has no practical use on a RS turbo unless running silly high boost. Forget them