So I am the new owner of an s2k with a comptech system. The s/c has a 9 lb boost pulley and an FMIC. The supposedly had a godzilla bov on it. When I drove it I noticed I was not making a whole lot of boost and instead of the typical bov sound I was just getting a loud, kind of fluttering noise. Thinking I should adjust the bov I started looking around under the hood for it

Starting at the FMIC, I traced the piping to the right side of the FMIC and after about 6" there was a break in the plastic piping via metal piece of piping and then back to plastic piping. Thinking the bov must be on the other side - attached to the metal piping- I managed to peak in through a hole and saw nothing. What I did see was a smaller black tube, maybe 1-1.5 inches in diameter that came out of the intercooler piping a couple inches and just stopped. It looked like something (like a bov) should be there but was not. I'm thinking the bov had been removed but no one plugged the hole... is it possible this is where my the fluttering noise is coming from??

Thanks... not really up on this stuff.

Because I am incapable of explaining this correctly...

 

Ok so just googled... evidently it is a Bosch BOV. Anyway, it sounds like crap. Thinking the shop probably switched it out on us. Is this even worth having? If not, what's next?

 

The SOS kits use a similar valve. Its purpose is to vent off boost when you are not on the throttle. The vacuum line (small line plumbed in from the left in your pic) essentially controls it.

You definitely need this or you'll be in boost 24/7 and wasting a ton of fuel when you're just idling or cruising at steady throttle.

I don't like the sound of mine either. I got a radiator hose and a filter from Pep Boys and routed the exit under the nose of the car so I can't hear it. Simple and easy to do.

 

That is fine, there would only be a hose attached to that if it was a MAF based engine management which required a recirculating blow off system, however it is not so it is perfectly normal to dump to atmosphere..as the picture shows.

"You definitely need this or you'll be in boost 24/7 and wasting a ton of fuel when you're just idling or cruising at steady throttle."
This isn't true a BOV will not dictate when your car is in boost, this is soley determined by rpm and position of the throttle plate on a supercharged car as to how much boost the engine is seeing, even if this wasnt the case the fueling would be fine as its determined by MAP pressure.

The fluttering noise is likely because you have a split in the small vacuum line that is leading to the BOV so it is not opening when you are on over-run/idle (or the bov is just faulty and sticking), the fluttering is from the air passing back through the compressor blades.

 

Thanks for the replies

I did some research on this particular valve and read some things suggesting these valves tend to malfunction at around 9 lbs of boost. I also read the internal diaphragm will eventually give out. I'm just wondering if it is worth the money to but a better made valve on there, for all I know this one isn't even functioning properly.

The fluttering really drives me nuts though... if I get on it and then lay off the throttle it will flutter until the RPMs drop low enough. My car is incredibly loud (motor/exhaust) but nothing compared to the fluttering noise. So you added a hose onto the vent and a filter to cut down the sound of the air venting? That's interesting... at this point i'm open to trying anything

 

Get a piston-type BOV, they tend to be more reliable as they don't have a diaphragm which can split. You can pick one up for a reasonable price.

 

Will do - any suggestions on piston-type brands?