I have the Agency Power BOV (recirc.) and 3" Buschar Racing intake pipe with cone filter. The question I have is, Does any one know how many lbs is the oem BPV on the Ralliart/Evo X. I currently switched back to OEM because AP BOV (recirc.) is fluttering to much and OEM does not, no matter how much I tighten or loosen it. I contacted AP and asked them why, they say its the spring and the one in it now is 7lbs. They said that they can give me a 11lbs spring but it will be to much.

 

Welcome to the world of aftermarket blow off valves.

Unless you are trying to run over 22psi you may as well stick with a stock evo x valve. I honestly saw zero difference between the stock RA valve and stock X valve... but I only run about 23psi max on the dinky stock turbo.

The only aftermarket valves I would consider are the forge RS (i've personally used them on my VIII and X and had not trouble adjusting it to not flutter but still hold boost great) and the syncronic (seems like all the tuners love them these days).