From out of nowhere surge!?!?

[stageup]

when i put the inlet on, it totally changed the way the car sounded with the bpv, i have a thread somewhere asking if anyone else's bpv sounded like a turkey or dove, i have not tried with the stock bpv as most people said that is normal. the 2nd set of youtube links posted is exactly how my hks + cobb sri sounded before the inlet

the first link by the OP is exactly how it sounded post inlet install.

 

[patty AT forge]

My guess is that the cap o-ring has failed and the upper portion of the valve can't hold enough vacuum to keep the valve open. This is causing the piston to open and close rapidly and making the "turkey" sound.

Perform the "pent-test" in this PDF and let me know what happens.

http://www.forgemotorsport.com/media/valve_service(1).pdf

Oops. Added link.

 

[schmitty]

http://www.forgemotorsport.com/media/valve_service(1).pdf

Oops. Added link.

Patty, I performed the test and when I remove the pen the piston travels down about 90% but doesn't snap closed until I remove my finger. Is this indicative of a failure? Also when I took the top cap off, the o ring was stuck to it, not on the valve body where it should be. I was able to place it back in it's seat in the valve body and the ring didn't seem to be malformed or have any cracks.

I have just installed the OEM BPV and am taking it for a ride now. I'll post back with my findings.

 

[schmitty]

The stocker is back on and works decent. No turkey, but doesn't hold much boost (~10-12PSI). Since it appears to have failed the pen test, it looks like I need to repair the Forge or get a dif BPV.

 

[patty AT forge]

Patty, I performed the test and when I remove the pen the piston travels down about 90% but doesn't snap closed until I remove my finger. Is this indicative of a failure? Also when I took the top cap off, the o ring was stuck to it, not on the valve body where it should be. I was able to place it back in it's seat in the valve body and the ring didn't seem to be malformed or have any cracks.

I have just installed the OEM BPV and am taking it for a ride now. I'll post back with my findings.

That is what it should do. The spring will push the piston down until the vacuum in the valve and the spring tension equalize (about 90% in this case), when you remove your finger the upper chamber of the valve equalizes with atmospheric pressure and the piston snaps shut from spring tension.

In other words the valve is fine.

My take on this (and it is the case with many cars) is this: Have you ever been in an empty house? Notice how much sound echos without furniture and pictures and the like hanging on the walls to dampen the sound.

The OEM inlet pipe is rubber, it insulates against this sound. What you are hearing is the pressurized air hitting the inside of the inlet pipe. It flutters due to pulses from the vacuum source causing the piston to move up and down a bit, if you're old enough you might remember a supposed "indian war cry" that kids would make by smacking their hands against their mouths while blowing out air, same thing is happening here.

 

[mazdaspeed32007]

i used the example of a big hall to a small carpeted room but i erased it because of my uncertainty in why he said his sounded more like a turkey than a normal throaty flutter.

 

[schmitty]

That is what it should do. The spring will push the piston down until the vacuum in the valve and the spring tension equalize (about 90% in this case), when you remove your finger the upper chamber of the valve equalizes with atmospheric pressure and the piston snaps shut from spring tension.

In other words the valve is fine.

My take on this (and it is the case with many cars) is this: Have you ever been in an empty house? Notice how much sound echos without furniture and pictures and the like hanging on the walls to dampen the sound.

The OEM inlet pipe is rubber, it insulates against this sound. What you are hearing is the pressurized air hitting the inside of the inlet pipe. It flutters due to pulses from the vacuum source causing the piston to move up and down a bit, if you're old enough you might remember a supposed "indian war cry" that kids would make by smacking their hands against their mouths while blowing out air, same thing is happening here.

I would be inclined to agree with you if the sound happened the same day as I installed the inlet, but that is not the case. It sounded like a little louder than it did with the stock inlet, until 3 days later then it started making the turkey sound.

I really want to believe that you are correct, however it seems unlikely that the acoustics changed with out there being some change in the way the system is operating.

 

[patty AT forge]

I missed that. Hmmm. When you did the pen-test did you just do it once or repeatedly? I always do it 10 times or so and rebuild the valve if it fails once.

If there was a marked change 3 days in then something must have failed. It could be the valve or a vacuum leak. If it is a vacuum leak it might be on the reference line to the top of the valve.

How did your OEM valve perform before you installed the Forge? 10-12 seems extremely low...

You can inspect the Forge physically and if need be I'll send you a rebuild for it.

 

[schmitty]

So i tested the BPV again today and it past the first 8 times I tested it. Sure enough on the 9th time it failed.

How do I go about getting a rebuild kit?

As for the stocker, I did some data logging with it this weekend and it will hold up to 15 PSI. My previous measurements were from catching glimses of the boost gauge.

 

[Jasnall]

You know that fluttering is not a good thing right? The valve should just open and let the air out....chhhhhh, not chh chh chh chh.
Am i wrong here?

 

[mazdaspeed32007]

You know that fluttering is not a good thing right? The valve should just open and let the air out....chhhhhh, not chh chh chh chh.
Am i wrong here?

it shouldnt...chh chh chh chh chh. sometimes it will flutter a little bit but not at WOT. should just open and thats it.

 

[patty AT forge]

So i tested the BPV again today and it past the first 8 times I tested it. Sure enough on the 9th time it failed.

How do I go about getting a rebuild kit?

As for the stocker, I did some data logging with it this weekend and it will hold up to 15 PSI. My previous measurements were from catching glimses of the boost gauge.

Just PM me your address.

 

[patty AT forge]

Just PM me your address.

Or send it to my attention and I will rebuild it:

Forge Motorsport
6536 Pinecastle Blvd Suite C
Orlando fl 32809

 

[schmitty]

Or send it to my attention and I will rebuild it:

Forge Motorsport
6536 Pinecastle Blvd Suite C
Orlando fl 32809

I'll be shipping this to you Monday. Thanks so much!