Can't Hold Partial Boost
 

recently i noticed that my car isn't holding partial boost. for example, when i try to hold 10-15 psi it drops back down to zero with a couple seconds. i can hear the air recirculating from the BOV (APS Twin Vent), but i'm not even letting off the gas. i did a boost leak test and nothing was leaking except for the BOV. I noticed that it was opening at 5-6 psi. i screwed the adjuster down all the way and my BOV started fluttering. i unscrewed it a little and it stopped fluttering, but it's still not holding partial boost. i recently installed an Invidia o2 housing and an AMS FMIC if that matters. what do you guys think it is? do you think the spring is weak in my BOV? i'm gonna see if i can borrow a buddy's stock Evo IX BOV and see if that changes anything.

Ive got the same issue with my perrin bov, there doesn't seem to be a good balance... it either vents too easily at partial throttle or when adjusted flutters like crazy.

I've got the perrin valve as well, I like it better than the APS which I had before. I have my Perrin set to where i like it, you just just have to play around with both adjustments. These cars just don't like partial throttle boost. It flutters a little but usuauly once I get into boost I just floor it anyways :)

I had this same issue when I was stock, even with the stock BoV. My friend told me that this issue arises from the stock turbo trying to keep the partial air flow on 1/2 throttle so the motor starts to sutter very aggressively, however I made 2 upgrades back then, went HKS BLACK series bov and Forge actuator which actually eliminated that issue :)

yeah it's just frustrating me because i'm pretty sure my car never used to do this. i'm gonna try to use a stock BOV and see what happens.

What did you adjust the flow for? more flow or less flow? ive got the spring tension about 4 turns tighter, it keeps from making the high pitched whistles but it still vents on partial boost but it also flutters at the same time. driving me nuts....

I've got it set to max flow and the tension is set pretty tight, although I just got a tune, so I don't know if they adjusted it or not.