The story is I won a spec r dump valve off eBay last week it turned up and was as described and quickly delivered so all good today I fitted it but it don't sound right it's very quite like its not building up pressure to dump ? My mate bringing in to work tomorrow a baileys twin piston to see if that is better . My question is am I right in thinking I'm sure I've seen some ware that spec r valves are for 16psi and up ? My sapps is a stage 1 265bhp if it helps ,hope some one can shed some light please