BOV tuning, how soft is too soft?

[dr1ftx3]

Right now I'm trying to get my Greddy RS tuned correctly, because after I replaced my vac lines on it for new ones, it stopped making any noise when it would go off. So now i'm trying to tune it so its sounding right. I've made about 2-3 whole turns soft, and now when my hood is open I can hear the WHOOSH, but still from inside the car I can't really hear anything. I'm just wondering how soft I should make it.

 

[DGajre777]

Too soft is when it blows before you reach redline or before the turbo holds full boost. Since it is recirculated, you might not be able to hear it as loud as a vented one.

 

[dr1ftx3]

Well there is a different kind of whistling sound when I rev the engine at lower rpms, is this any sort of problem?

 

[GSntncT]

He's absolutely right. It's the same thing when adjusted the valve on my RS. When I first drove when it was installed, I couldn't hear it at all.

I 'softened' it quite a bit and was able to hear it, but considering I use to have the TurboXS RFL I was like WTF????? The Greddy RS is more along of a recirculating type BOV, not a venting style. It really won't be loud at all even when you do soften it.

To answer your ? dr1ftx3, no. The Greddy RS valve will flutter at lower rpms.....not enough built up air pressure at low rpms to 'blast' the valve.

If you set the RS hard enough, the valve won't open no matter what speed/rpm. Period.

 

[pinder91]

When it's TOO soft it will leak like a mofo. Patience is key when setting up the spring.

 

[dr1ftx3]

Ok, so GSntnct, your RS is also barely audible? And how do I know when I have a leak?

 

[95TalonOwner]

What you could do to check for leaks (this is what I do) is take off the recirc hose and start adjusting it. Then rev the engine to build up some pressure and see if and air leaks out. I don't think this is the best way and you could probably just use a boost leak tester, but thats what I do once and a while to make sure everything is still good.

 

[GSntncT]

I wouldn't say barely audible, just not nearly as loud as my old Turbo XS. I have recently set mine pretty hard, cause I don't really care for the sound anymore. A boost leak? When hard on the throttle, you will NOT hit the psi level you were hitting before, you may hit 5 psi at the most.

9 times out of 10, an intercooler pipe/clamp has come off. If you are on the stock UICP( didn't look at your profile) it may have developed a tear. Also, you may hear hissing that wasn't there before.

if the only issue you have is the RS not being loud enough, but you are hitting your typical PSI level, then it WILL NOT be a boost leak.

 

[95TalonOwner]

Also if you are recirculating and have a small leak from the bov being too soft, you will not loose as much psi because the pressure you are losing is looping back in the intake therefore your turbo will just have to work harder in order to achieve whatever boost level you are at.

 

[dr1ftx3]

I turned it soft a little more for the last time and when I test drove it, It seemed like I was getting MAD boost creep, like 4 psi over what i'm boosting at.

 

[MyBeatGSX]

There's no such thing as full soft, and it should be set full soft.

Contrary to popular belief (and I've said this a million times) full soft will not leak under any boost. If you run 90psi, you will have 90psi trying to push the valve open, but you will also have 90psi coming through the vacuum line plus the spring pressure holding it closed.

The adjustment is for large engines or engines that make high vacuum so the valve doesn't pop open when you aren't even boosting. Its there to adjust for vacuum, not sound, not boost etc.

 

[dr1ftx3]

Ok so you suggest I turn it soft until I can't anymore?

 

[95TalonOwner]

If you did that, the screw would fall right out. What you can do is back out the screw all the way, then start screwing it back in and when you feel a small tension on it, stop.

 

[DGajre777]

There's no such thing as full soft, and it should be set full soft.

Contrary to popular belief (and I've said this a million times) full soft will not leak under any boost. If you run 90psi, you will have 90psi trying to push the valve open, but you will also have 90psi coming through the vacuum line plus the spring pressure holding it closed.

The adjustment is for large engines or engines that make high vacuum so the valve doesn't pop open when you aren't even boosting. Its there to adjust for vacuum, not sound, not boost etc.

If I go full soft on my Type S, it blows off at 6000 RPMs while driving. If what you say is correct, then maybe something is wrong with my blow off valve!

All those running the Type RS and saying that it is not loud, are you guys venting? and if you are, are using the vent attachment? It is supposed to suck air in around the sides to make the blow off valve sound louder. Here's a pic of the vent attachment installed on the RS:

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I reason I ask is because I plan on getting a Type RS and venting it with the GM MAF/MAFT.

 

[zaldivarbigboy]

Hey guys I have been using the Type RS BOV for a while now and its pretty loud at hi rpms when I shift. Not only that its also true that at low rpms it dosent blow it just whistle. But It sure is loud if I let it go enywere after the 4.5 rpm range.