The Aeroflow Performance wastegate has a variety of springs to suit different boost levels. Pre-installed with 1 Bar (14psi). Different spring combinations may be required to suit different boost requirements and tuning which are sold separately please refer to chart for moreinformation on these springs. The tuner can use combinationsof up to 3 springs to achieve the base boost pressures required. To aid in the identification of these springs they are colour coded.When selecting your spring rate, the total boost psi pressure is determined by adding the spring rates together. Wastegate spring selection will determine the minimum and maximum boost pressure that you want to run,and your control method. Care should be taken when selectingboost pressures until the engine can be run on a dyno toensure safety. Always consult an expert when making boost changes, and it is recommendedthat the car be checked on a dyno, as high boost and/or lean air/fuel mixtures can cause engine damage or worse, total failure.