I had a strange occurrence last night. I experienced very low boost during my normal 20 minute commute. I was not able to boost and was limited to -5 in-hg. I checked all the hoses and everything seemed to be ok. Today I start up, I can hear and see the supercharger spinning. Still not getting any boost during the short drive, then all of a sudden I get boost. I checked all the hoses and there are no cracks and everything is tight. Could it be that the valve is stuck open?

I do notice oily residue at the output of the blow off valve opening. Last time I cleaned the air filter, I saw some oil residue inside the supercharger housing. I'm thinking the Blow Off Valve is stuck and needs cleaning, but maybe something else is causing it to gunk up?

External supercharger housing and associated hoses looks fine.

 

I wonder if could modify a HKS BOV to work with a Jeep I had one on my STI it worked great it was a little loud for my taste though.

 

It is possible the valve is sticking open, though the low vacuum you mention points toward a leak in the intake manifold somewhere.

RIPP

 

I cleaned the valve and it seems to be back to normal. Maybe I'm paying more attention to the gauge and sound, but the valve seems to be dumping air at aroun -5 in-hg. It "closes" (aka sound goes away) around -3 in-hg. Is this normal?

 

Yes it is.