A bleed valve 'bleeds' off boost pressure before the actuator, fooling the actuator into thinking it is running lower boost than it really is. The main problem with bleed valves is that although cheap, they raise the boost pressure without allowing the ECU to make adjustments to the fuelling, which can cause the engine to detonate or 'pink', leading to premature wear and engine damage. They also remove the boost limit, rendering the ECU unable to shutdown the engine if a problem should arise.

This is a cheap and fast way to increasing performance and a faster way towards engine problems, it has been proven time and time again.. To say that the problem of bleed valves is related only to people who play with them is incorrect, they ignore many of the basic requirements of the engine and remove protection... and you believe this is OK or that nothing is wrong with it.

I would never ever use a tuner who thought that removing boost limits or fitting a device which allows an engine to detonate though its basic design flaws was acceptable