Yeah it needs to be pushed to the buttom of the tank. I had some problems whilst getting it mapped because i didn't fit it correctly. it needs to be pushed right down
problem was the penny didn't drop with me until i wasted 2 mapping sessions
Lots of poeple use them in the states and it does produce 4bar pressure. just be sure to install correctly and monitor it for couple of times when your in reserve.
PM me for details
cheers addo