If you are finding that the valve is dumping more than required or you are loosing boost pressure it is normally an indication that a stronger spring is required. Conversely if the valve is failing to dump it may be necessary to install a weaker spring. If during this tuning of your valve you are faced for example with the red spring being to strong and the blue spring to weak, you can add the spacers to the blue spring to increase the tension by small increments, thus achieving a setting between the red and blue springs.