Have you dialed it in yet? You will need a voltmeter and an assistant.
No i will have to take it to Simon's shop then But i took it out for a couple of wot runs and it cut out still at 15 and i tryed it at a bunch of different positions.
I wouldn't attempt to dial it in without a digital voltmeter. I installed +20s beforehand just to be on the safe side. I have them installed on two of my cars and they both took a few WOT runs to get dialed in precisely (withing .1v of overboost cutout). You should install it inside the car so it can be dialed in at WOT.