Whenever I accelerate partial throttle (up to -2 to 0 psi, my autometer boost gage shows) when I let go off the gas, the blow off relieves some pressure. Isn't -2 to 0 psi still vacuum?
Or is it my gage that is inaccurate?

 

as you place a little load on the engine, the tubo will start to spool, even though you let off the gas, the turbo is still spooling slightly, pushing through the pipes towards you throttle body. When you let off the gas, the throttle body closes and that pressure has to go somewhere so it vents out the blow off valve.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by mike1114 &raquo;</TD></TR><TR><TD CLASS="quote">as you place a little load on the engine, the tubo will start to spool, even though you let off the gas, the turbo is still spooling slightly, pushing through the pipes towards you throttle body. When you let off the gas, the throttle body closes and that pressure has to go somewhere so it vents out the blow off valve.</TD></TR></TABLE>

Yup... mine does the same thing, no big deal.

 

Most aftermarket BOVs don't do this because they take some boost to open. My DSM BOV blows off after every gear shift, though, even when cruising.

 

If you blow off before reading any boost your BOV spring is too loose. Or so I have read per Jeff Evans ((IIRC)

 

Thats correct. I set my HKS SS too loose and it blows off everytime im over 50% throttle. It was cool at first but now its just annoying.

I wonder if having it too loose can bleed boost when you dont want it too.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Boltz &raquo;</TD></TR><TR><TD CLASS="quote">If you blow off before reading any boost your BOV spring is too loose. Or so I have read per Jeff Evans ((IIRC)</TD></TR></TABLE>

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Muckman &raquo;</TD></TR><TR><TD CLASS="quote">Thats correct. I set my HKS SS too loose and it blows off everytime im over 50% throttle. It was cool at first but now its just annoying.

I wonder if having it too loose can bleed boost when you dont want it too.</TD></TR></TABLE>

Thanks for the tips guys, I think this is what's happenning in my case. I have an HKS SS also. How do I adjust the spring?

 

Remember you can set the BOV however you want it to blow off. You want the most Blow off possible so your turbo can continue spooling with no resistance, so technically it should be as loose as possible so that it just barely holds the valve closed in boost. When you let off the throttle it set to bleed immediatly and continue so until more boost is formed...geti it? Of course in the real world it really doesn't matter at all. You can set it however you want, personally I like a little blow off past 40% throttle so I set it for that. If you don't like it turn your adjustment **** tighter (if you have one) or add washers or crush it (for the DSM BOVs)

 

my greddy type s blows off in real low vacuum as well. its related to load on the motor. its rather normal though

 

completely normal!

 

ANy hint how I can adjust this in my HKS SS BOV?

 

there should be a hex nut that screws in and out on the back. That should be ur adjuster