I put a Tial q bov vta on my evo 9 running speed density. At idel the bov opens a little and let's air out with a small hissing noise... And sometimes when I don't hit full boost it reacts weird. I have a 10psi spring in it and didn't know what spring to get because the car didn't come with a gauge. Do I have the wrong spring? If so what spring should I get? I know I need to know the vacuum to find out the correct spring but I don't have a boost gauge yet to know that. Thanks in advance!

 

You have already resolved your own problem in your post.... You need a gauge.
Then you will know what spring to purchase...

http://www.tialsport.com/documents/w3_tial_qqr_sp.pdf

 

Unless he has a 3/4 bar map sensor, a tactrix cable, and evoscan.

 

you have plain spring. usualy white fix the problem.fixed mine.

 

So the hissing and air coming out during idel isn't normal?

 

I'm not sure if it's normal or not but I didn't like it. Since you are on SD it's not effecting anything. Try to shim it with washers before you go with different spring or if you can live with that just leave it. I know on tial QR is normal because it's recirculating valve.

 

Ok thanks, I think I'm just going to leave it because it still runs good with the bov on.