What's the Hard/Soft Bov settings for?

[phunny]

I have a Greddy RS Bov and I'm wondering what the hard and soft settings are for? I really have no idea what they do and I can't boost over 16psi with my MBC. Just wondering if mabybe this can help me out.

 

[JusMX141]

"Hard" will add more spring tension, enabling the valve to hold more boost. The problem with it being too stiff would be that the valve wouldn't open properly at low boost which would make the valve "flutter". Too much spring tension would lead to compressor surge of the turbo, which will trash the journal bearings in no time.

 

[daren_p]

^Exactly, normally you want to set it soft enough that you get a nice solid boost release (ie no flutter or surge) but it still being stiff enough to hold the amount of boost you plan on running. I know back when I had a type RS, with my perticular setup I had to adjust it basically as soft as it could go to get it to blow off correctly. This was even softer then the factory setting but it still held the 20 or so psi I was running at the time, no problem.

 

[92AWDHX40]

Thanks that seems to be my problem as well, i get flutter on my greddy, ill change the settings. Thanks for the turbo juxs, love it.

 

[gsx ftw]

I get slight flutter on the softest setting under low boost...well what I assume is the softest- when the nut is on the threads and not even touching the valve body?

 

[daren_p]

I get slight flutter on the softest setting under low boost...well what I assume is the softest- when the nut is on the threads and not even touching the valve body?

The nut is just there to lock the adjusting bolt in place, it has no effect on the spring tension setting. To set to the lowest spring pressure, you want to hold the bolt in place with an allen key & losen off the locking nut several turns so it doesn't get in the way. Next it would be a good idea to completely remove the adjusting bolt & coat the lower threads with some teflon paste or pipe dope if you haven't already done so (common place for a boost leak) Then again use the allen key to turn the adjusting bolt in to the point where you feel it contact the top plate of the spring assembly. This will be the point with the least amount of spring pressure. When the bolt is in the correct adjustment position for you, tighten the lock nut back down by hand & once there's resistance, use the allen key again to keep the adjustment bolt from moving & lock the nut down with a wrench. When doing this don't apply a tonn of force as I've heard of many people stripping the hat, with too much torque.

 

[phunny]

Hmm, so if I adjust it to make it harder it just might let me up my boost a little. And I'm guessing I'll hear the flutter if it's not adjusted right?

Great info btw.

 

[daren_p]

Hmm, so if I adjust it to make it harder it just might let me up my boost a little. And I'm guessing I'll hear the flutter if it's not adjusted right?

Great info btw.

I would guess more then likely, probably not. If your only able to hit 16psi, even on the lowest tension on the Greddy, it should easily hold 20 or so psi. Probably have some other issue. Before you go adjusting your BOV, have you done a boost leak test first? This will verify if you have other issues & also if the BOV is currently leaking & needs to be adjusted or repaired, etc.

You are correct in that yes, if you adjust the spring tension too hard you will start to hear flutter &/or compressor surge.