Tial BOV openeing at idle

[crf_rider]

Hey guys,

I have a Tial BOV with an 11 PSI spring (and I have added a .032" shim). At idle my rpm's start to fluctuate (500-800rpms) and the BOV opens and closes. My EBC says I am pulling about -51cmhg.

1 PSI = 5.17149 cmHg so -51cmhg = -9.86psi. The sping should be plenty stiff no?

I have checked for air leaks and cant find any. The BOV is connected to the larger vac hardline that runs beside the 3000 pipe (3 hardlines connected, one for ISC and the small one went to stock BOV).

So why is my BOV opening at idle?

 

[socc924]

my car did it with the 7 pound spring in a tial bov... I need to get a 9 psi spring. The only thing I can think is that maybe you have a weak vacuum source going to the bov?

 

[crf_rider]

A weak vac source would cause it to not open. If I pull the vac souce off the BOV stays shut.