right, i think dump valves are crap, but the guys asking how to fit one, not what all of uslot think so.......

Obviously fit the dump valve into the boost hose, then run the vacuum pipe from the dump valve and 'T' it into the vacuum pipe that runs to the ECU. Make sure that everythings tight(no air leaks) and if the car stalls, then the dump valve is stuck open, allowing un-metered air to enter the system, causing the car to stall. hope thats some help
Oh and if you need some T-pieces, go and get some from Halfords, theyre all next to the window washer pumps and hose
Danny