The bov was working fine a couple of days ago. I put on a KN filter onto my turbo and now its fluttering like crazy. The BOV has its own vac source straight into the Intake manifold. i have about 19 in of vac. I'm not sure what spring is in there. But I assume it should work fine cause it was working fine before? I tried taking the filter off also.

 

take it apart and put it back together might be seize up

 

you were right...i just took it apart and it is seized. i will update you guys

 

this same thing happened before i got my tial 50mm....my bov was sticking and until i ran a filter i didn't notice it....once i had the filter on there, it started fluttering a lot more, but it was actually compressor surge

 

a lot of people get compressor surge and "bov fluttering" mixed up. COMPRESSOR SURGE can sound just like a fluttering blow off valve. Kinda confused me a couple of times.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by SPOOLINmatt &raquo;</TD></TR><TR><TD CLASS="quote">a lot of people get compressor surge and "bov fluttering" mixed up. COMPRESSOR SURGE can sound just like a fluttering blow off valve. Kinda confused me a couple of times. </TD></TR></TABLE>

Does this fluttering you guys are talking about make noise or is it quiet and the bov is just opening and closing?? Just curious.

 

no its loud and it happens exactly when the BOV would make its sound.

 

Good info.

 

all of a sudden my spring load is too heavy? I need to get a 9 lbs spring or something now. cause i can rev it up and get some boost and let go of the throttle and the bov will not open and cause the compressor to surge.

 

what spring are you using now? you said you have 19" at idle so the 9lbs spring should work fine, it might be a little light i guess. tial does recommend the 11lbs spring for 18-21"

 

^^^ I have also read that. I will be using an 11 psi spring. Your vac line inside diameter needs to be fairly large to provide ample vac to the valve.

 

i have a 7lbs spring now and it still flutters at low boost. what diameter hose should i use?

 

6mm ID minimum
get an exact reading of your idle vac at operating temp, only then can I tell you what spring you need

 

i'm at about 18-19 in of vac at normal operating temp. i am using 1/4 hose directly to a 1/4 nipple off my victor x.

 

between 18 and 21 is an 11psi spring

 

i'd like to use 1/4", but i guess the nipple on the bov isn't that thick

 

nipple on the BOV is .2845in (7.22mm)

 

if any one wants to know what ompressor surge sounds like , listen to the WRC rally cars , they dont run BOV , ive always wanted that sound but then found out they dont use them lol

keep in mind they probly replace a turbo every few stages due to surg and the antilag systems