LEYO Motorsport is offering a wide range of BOV springs to match the correct rates to suit your turbo needs. Example Blue and Red springs are upgraded for custom tunes or any other high stage tunes. These Blue and Red springs are not included in the standard BOV or DV kit - Only Sold Separately. They are suitable for higher performance tuned vehicles. Below is a reference chart for calculating the correct spring rate for your specific turbo and engine setup