BOV Problem?

[EclipseParty]

Ok.. So.. I have a Greddy Type-S. When just cruising and all, its super smooth and sounds good. But, when I really "get on it", i get this incredibly loud whistling sound that I believe is coming from the BOV. I can post a video for anyone to see and get a better gist of what it sounds like. I don't know much about these cars yet, but i'm learning i suppose. So, the true question here is, what is making it make that noise or if it even is the BOV?

 

[greydelta38]

It's probably the turbo. In cruising speeds, they're quiet under no boost. But when you accelerate, they naturally make a whistling noise. That's good that it is. It means that it's sucking a lot of air, and when you let off the gas, the BOV screams to let out the pressure built up. The louder the better, because it means that more air is being pulled in and let out. Turbos naturally make whistling noises, to put it simply.

That's just an assumption, though. If you think something's really wrong, like it's whistling but you're not getting any boost, or you think there's a leak, go ahead and post a video and we can tell.

 

[csmwiese]

Sound like your BOV is set at to low of pressure, as soon as the turbo increases the boost the BOV lets pressure (boost) out. You really need a dyno to set it correctly. Just adjust it so it only makes noise as soon as you let off the throttle. Just my 2 cents.

Clint

 

[WES_393]

I agree, it sounds like the BOV is too loose. Guys will set the BOV loose so it makes the cool "whoosh" noise. Loosen the lock nut (if there is one anymore) and tighten the hex-key bolt a turn or two. That should stiffen the spring.

 

[98zx23369]

could be a boost leak at a silicone connector, do a BLT to check

 

[007jimmy]

could be a boost leak at a silicone connector, do a BLT to check

I agree with a boost leak test. Air is leaking somewhere causing the noise you describe. Get that soapy water ready!

 

[csmwiese]

If it's an Auto, powerbrake it up and build some boost and have someone see where the noise is coming from....if you don't have a leak tester. I'm still betting BOV not set correctly.

Clint

 

[Bud92gsx]

Tighten the bov, from the nut at the top..You may also want to put in the larger spring..That should help keep leaking down as well.But try tightening it first and see what happens..

 

[FIBA M - EC17PSE]

Im having this same issue with my new ngr type s, I did the single spring mod but it still whistles so I might have to add the other spring again, just open yours up to see if its not had the big spring removed by any chance, ive been told to heat up the spring and stretch it as that will add more pressure on the valve,

 

[EclipseParty]

Its not the turbo spooling, i know THAT whistle.. Its louder than that. First ill tighten the spring down to see if that works. If that doesn't, ill do a BLT. Because my intercooler and piping is in some rough shape. So, one of those connectors may not be tightened down all the way. I can post a video here later if its still doing it.

 

[Henny101]

Definitely check for a boost leak

 

[Tyeler18]

While you're checking for a boost leak you can adjust your bov to the pressure setting you want. Just fill the intake tract to say 5+ psi above what you boost to and tighten the screw until it doesn't leak at that pressure. Then check for leaks. Kill 2 birds with one stone.

 

[turbotom]

Sounds like a boost leak to me, now for a veteran of the TYPE S bov (I love those BOVs) they make the loudest sound that pretty much scares away honda boys,. The only bad thing about them it the rubber diaphram will rip a hole and leak. Now if you get a china bay ones for $25 and use the parts, it's the same and it can be repaired. Do a boost leak test and go from there.

 

[NHerron]

While you're checking for a boost leak you can adjust your bov to the pressure setting you want. Just fill the intake tract to say 5+ psi above what you boost to and tighten the screw until it doesn't leak at that pressure. Then check for leaks. Kill 2 birds with one stone.

You got to realize the OP might not know what that spring is designed for, so by reading this he might figure the spring holds boost all by itself. And no one wants to look dumb around other car people by saying their BOV is adjusted for 25psi

To do it right, set the spring adjustment by applying the highest vacuum reading seen (such as HIGH RPM deceleration) to the BOV diaphragm, then tighten the adjustment until the BOV is closed.

 

[csmwiese]

That sound like a great idea.....set your BOV the same time you do a leak test

Clint

 

[NHerron]

The bov should hold closed no matter the adjustment setting, as long as the signal line is hooked up and theres no rip in the diaphragm. Adjustment is based off vacuum, not boost.

 

[Total Eclipse]

As far as the whistle/whinning, pull the intake off the turbo and check for shaft play. I have seen turbo's with enough shaft play up and down that the impeller blades on the compressor wheel will rub the aluminum compressor housing and whine. louder with more boost, as the blades are spinning faster.

 

[Ludejim]

But, when I really "get on it", i get this incredibly loud whistling sound that I believe is coming from the BOV.

This very well could be the BOV opening when too much boost is being built, although this usually creates a fluttering noise (the turbo system builds boost and then the BOV releases some then closes and this happens over and over, aka BOV flutter).

It could also be your waste gate. Whether internal or external, your waste gate may be opening to alleviate the excess pressure being built up by the turbo (this is the way that it was meant to function). If your boost gauge (hopefully you are not using the stock gauge) tends to steady when you hear this noise, then it is most likely your waste gate doing its job.

I think you need to be 100% sure where the noise is coming from before spending any money.

 

[csmwiese]

From the thread title and his first line, this problem sound like it started after the BOV install.........it's the BOV set too low. adjust it and let us know.

Clint

 

[EclipseParty]

Thank you all. That really does help, Ill make sure to get back to y'all as soon as i either fix it or find out what the hells going on.

 

[sethpatch]

We finally figured out what was going on with Eclipseparty's bov, apparently the previous owner stripped out the threads on the adjustment screw. I thought about re-threading it by drilling it out a-little then using a bigger screw. Has anyone else had this issue, or thinks it would be a good idea to to fix it with my idea.

 

[VTDSM28]

Sounds like its just loose. you could try replacing it too?

 

[NHerron]

Not a bad idea, I would probably do the same thing. Also sounds like a knockoff valve, if it is you might wanna get a good brand name

 

[sethpatch]

Sounds like its just loose. you could try replacing it too?

Not a bad idea, I would probably do the same thing. Also sounds like a knockoff valve, if it is you might wanna get a good brand name

I promise you its not just loose. I have been working on these cars for years and trust me the threads are literally coming out of the top and are on the bolt.

The bov is a real greddy, someones just fubar'd it probably because they didn't know what they are doing. We've talked and chances are it's getting replaced with a synapse.

 

[NHerron]

Right on, good luck with it!