my mate bought a 50mm T-piece and cut the pipework just before the inlet manifold, plummed it in there. it seems only a twin piston valve works without stalling, a forge twin pistin one was perfect, block both the pipes from the standard re-circ dump valve (i used cut down bottle tops) and go for a boost!
the twin piston forge kept it from stalling and still dumped off really well, didnt lose any MPG either.
i have a spare pipe with a T-piece plummed in ready as i was going to fit one to mine but need the cash for other things at the min

my spare pipe and how to fit it.

as you can see the dumpvalve will sit right at the front
if any one wants it gimmi a ring on 07737071355