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3 minute(s) of a 643 minute read
4-1-2012
Ask and you shall receive!
I took it easy on the shifting, so you could hopefully hear the valve better. I also did plenty of partial boost shifts so you could hear that it doesn't flutter (like I've had problems with). Unfortunately I had the driver's window up (and the other 3 cracked), so you can't really hear it as well as you could if they all were open. We'll see if I get tired of it or not. Right now I really like it. It seems very responsive, and really isn't all that loud.
4-2-2012
I don't know if it's necessarily a case of power level requiring a BOV, but more so just trying to get the most responsive setup. I would argue that a recirculating valve is theoretically best for a MAF based system. All metered air should technically stay within the system. It is more that the VTA valve isn't really that bad, and that this valve is able to adjust more than the Forge.
The Forge valve has a piston design that has much greater area on the top side. This results in a net force downward (closing the valve) under boost. Really, no matter how light your spring is, the valve will still close tightly and hold boost. The downside with that is that it is always open under vacuum, and even very low boost. You could get it to close with a very stiff spring (stiffer than they include), but it would have a lot of compressor surge.
The GFB valve has similar area on the top and bottom side (possibly slightly more on the top). This essentially means the piston is neutral based on air pressure. The spring holds it closed. Correct spring pressure is much more crucial here. If you have it set up correctly, it will close at idle (unlike the Forge), and still blow of very rapidly. Another side benefit of the 50/50 Hybrid valve is that there is essentially twice as much flow area (so it vents more quickly).
Really the Forge valve (or similar design) is probably best for the vast majority of people. It is essentially plug and play. You really should be able to install just about any spring, and it will function fine. It will always close tightly (and always hold boost unless the piston sealing surface is dirty or damaged). Other valves simply offer more options for adjustability (which for some people could just be more ways to screw them up). A recirculating valve that closes at idle may actually be the best option (as long as you take the time to set it up correctly), but for now the GFB valve seems to be doing the job.