I'm not having any problems. If I ever boost over 30 psi, then I'll need to add the connection to the EBC.

 

I have done the mod you guys are talking about and the problem I found is that ends up with too much bias on the top port. The best thing to do is to replace the unit with a blow off valve which is proportioned and designed for the kind of throttle response you desire be it preset or adjustable. I have had really good luck with the greddy type s. You only use the top port on that blow off valve while taking the small spring out of the top unbelievable throttle response and very good boost holding capabilities . Jerry AKA 94 AWD Coupe can attest to this. Lots of blow off valves overcomplicate the concept of differential pressure control. My questions centered around what manufacturers were calling a limit to horsepower on a blow off valve or bypass valve and I have found that they probably refer to flow able to be vented in one shunt. However in the grand scheme of things a very responsive turbo will need a much differently tuned blow off valve versus a larger lagir blow off valve. Currently we are using a greddy type fv. If you look at the design of this valve it's very simple and it even offers a very good benefit of acting like a check valve and that it only vents when there is positive pressure in the intercooler pipe. This can go two ways we have found that turbo shaft in speed will stay higher with a boost leak so light lift on the throttle with a valve like a standard Type S will allow more consistently higher shaft speed which is typically the goal to prevent any turbo stall or surge buy venting as much as possible when needed. The FV vents very easily however the separation in the Piston shaft allows a dampened effect on the shunt. If you lift the throttle and there is positive pressure in the intercooler pipe it will vent very nicely clearly and loudly. I have played both sides of his card equally I typically like my blow off valve to leak at idle very slightly because of the larger size piston pushing the valve closed versus the smaller size on the intercooler side this will still allow the valve to seat and stay leak free. The the issue then becomes how direct route is your vacuum line and how sensitive is your vacuum line to the differential present. 240 Z twin turbo played with a mechanical valve which closed the bottom part of his tial wastegate that he was using as a blow off valve above a certain PSI if I am not mistaken I believe he found this acted like a light switch effect with throttle and torque or power output a better algorithm may be needed to effectively execute this design the smoothest. The biggest detractor to adding these kinds of features I see is complexity and lack of consistent control.