From what I've experienced with blow off valves is that if the spring tension is too great, then the valve will not open unless you are running high amounts of boost. It's a tradeoff of response vs. staying shut under high boost. If the spring tension is too loose, the blow off will open up under boost and cause a leak. From the Option Tsukuba Superlap videos I've watched, the TypeR blowoff valve on the Jun Lancer gets a little surge, but you can hear the pshhhh when it opens up if you crank the volume up a bit.