From out of nowhere surge!?!?

[schmitty]

I originally posted this on Mnmazda, but I have kinda hit a wall in diagnosing this so your feedback is welcome.

Last week I upgraded my inlet and added a boost gauge. Everything ran well on Saturday and Sunday. Yesterday I take the car out in the morning and it runs fine. I go out in the afternoon , everything is fine on the way to lunch. On the way home while getting on the highway, I accelerated down the ramp (15PSI boost) clutch to shift and it sounds like I have a turkey in my engine, then the BPV makes it's mario coin sound. This continues every time I boost more than 5 or so PSI.

I come home, and change the spring in the BPV (was blue with no shim, so I swap to yellow with no shim) and no more turkey sound but, it wont hold very much boost.

Today it surges again and i check all the hoses I can without removing the battery box. AFAICT all the hoses are on and in good condition. The hose coming off the BPV (the big one) is on but is easy to slide off with out moving the clamp. I also saw that the tube going to the boost gauge solenoid is pinch so I freed it up. Rev the engine and BPV works fine a low boost, go out and test drive, anytime i get above 5PSI it gobbles, then the the BPV *chings*

So I am thinking that the BPV isn't operating fast enough, which could be remedied by using the softer yellow spring, but then it won't hold the proper amount of boost.

So far I have tried all spring and shim combos, and swapped with a known good Forge BPV. I also upgraded the clamps on the BPV and inlet.

Here is a video I made of what it sounds like. Any feedback is welcome. http://tinyurl.com/n2tmr3

[I`m Batman]

how old is your BPV? Does the valve still open smoothly and easily by pushing it? You may just have to clean it up and lube it up again.

[schmitty]

Yup opens fine. Plus the problem existed with a known-good forge.

[MSMS3]

Are you saying that you tried another Forge and it did the same thing?

If so, it's got to be in the tubes and clamps somewhere.

If you have not substituted a known good BPV, do you still have your OEM BPV sitting around? Substitute it to see if the problem goes away. If problem is then solved, either leave it on or get a new, good Forge.

[Bravnik]

At first I thought it was just flutter, but that does not sound anything like my old forge sounded. I'm sorry but I would check all connections again as to me that does sound like Surge a bit to me.

[dmention7]

We checked the connections at least twice... they all appeared okay.

One thing I was suggesting is that he said the BPV connection on the TIP (you installed that the same weekend too, right Schmitty?) is located closer to the actual turbo inlet than stock. So I was wondering if the recirculated air from the BPV was causing turbulence at the compressor inlet, and if that was the source of the surging.

[schmitty]

I went through and reinstalled the inlet. Double checked all lines, tightened all clamps. Still surging.

[HOBDisease]

If you have not substituted a known good BPV, do you still have your OEM BPV sitting around? Substitute it to see if the problem goes away. If problem is then solved, either leave it on or get a new, good Forge.

Try that.

[Bravnik]

I might be worth it to go VTA just to see if it stops the surging. That would answer the question of if the BPV being closer to the Turbo makes a difference. You will need to cap off the recirc hose to do this.

Shy of that, I don't know what to tell you. With your mods and the Forge you should easily be able to run the blue spring with 1 shim even.

Is there any chance something got dropped into the turbo with the Inlet install? I find it strange that it ran just fine for a day or so then started surging.

Have you checked and tightened all the clamps on the hot side to the throttle body to ensure your not leaking there? Not sure if that would make it surge but maybe?!

[patty AT forge]

I might be worth it to go VTA just to see if it stops the surging. That would answer the question of if the BPV being closer to the Turbo makes a difference. You will need to cap off the recirc hose to do this.

Shy of that, I don't know what to tell you. With your mods and the Forge you should easily be able to run the blue spring with 1 shim even.

Is there any chance something got dropped into the turbo with the Inlet install? I find it strange that it ran just fine for a day or so then started surging.

Have you checked and tightened all the clamps on the hot side to the throttle body to ensure your not leaking there? Not sure if that would make it surge but maybe?!

Single piston recirc valves can't be run VTA. They will be open whenever the manifold is in vacuum and you will have the mother of all leaks.

[patty AT forge]

I originally posted this on Mnmazda, but I have kinda hit a wall in diagnosing this so your feedback is welcome.

Last week I upgraded my inlet and added a boost gauge. Everything ran well on Saturday and Sunday. Yesterday I take the car out in the morning and it runs fine. I go out in the afternoon , everything is fine on the way to lunch. On the way home while getting on the highway, I accelerated down the ramp (15PSI boost) clutch to shift and it sounds like I have a turkey in my engine, then the BPV makes it's mario coin sound. This continues every time I boost more than 5 or so PSI.

I come home, and change the spring in the BPV (was blue with no shim, so I swap to yellow with no shim) and no more turkey sound but, it wont hold very much boost.

Today it surges again and i check all the hoses I can without removing the battery box. AFAICT all the hoses are on and in good condition. The hose coming off the BPV (the big one) is on but is easy to slide off with out moving the clamp. I also saw that the tube going to the boost gauge solenoid is pinch so I freed it up. Rev the engine and BPV works fine a low boost, go out and test drive, anytime i get above 5PSI it gobbles, then the the BPV *chings*

So I am thinking that the BPV isn't operating fast enough, which could be remedied by using the softer yellow spring, but then it won't hold the proper amount of boost.

So far I have tried all spring and shim combos, and swapped with a known good Forge BPV. I also upgraded the clamps on the BPV and inlet.

Here is a video I made of what it sounds like. Any feedback is welcome. http://tinyurl.com/n2tmr3

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.

[Bravnik]

Single piston recirc valves can't be run VTA. They will be open whenever the manifold is in vacuum and you will have the mother of all leaks.

Ah good to know. Thanks for the input.

[Shiroi_ms3]

I kinda have the same thing going on, every time I hit boost it makes this fluttering sounds, I have the PG Turbo inlet, COBB SRI, and a Type S BPV. I thought it was just noise of the air going through the TIP because it's stainless steel, but now I am worried that it might be surging and I know that can hurt a turbo.

[mazdaspeed32007]

i know a few different people including me that have funny sounds with the turbo inlet. i have the same set up....sri, turbo inlet, and forge bpv and mine makes what sounds like a sort of surge but i think it comes with the inlet. not surge....just the wierd noise. a friend in the ms6 section has an inlet and his makes a funny noise too. mine is sort of covered up by the mario coin but his is not because he doesnt have the forge.....food for thought. maybe it is surge and this needs to be figured out soon....OR ELSE!

[Bravnik]

Flutter is normal under partial boost. Under full boost you should get a Phoosh and no flutter. Surge is something completely different and kinda like the OP's video.

This is what Flutter sounds like and what my car sounds like in low boost.

http://www.youtube.com/watch?v=09ji7OSfXg0

http://www.youtube.com/watch?v=RUZLmJ3ampM&feature=related

[mazdaspeed32007]

I know the sound you speak of....its just a louder deeper sound of the BOV releasing. i took my car for a ride and duplicated it perfectly.

[schmitty]

Thanks for all the good feedback everyone, getting this type of help makes me glad I am in the Mazda family.

Another update - I removed the hose going to the boos gauge and replaced the T with a regular two ended connector, still has the same problem.

I will try the "pent-test" as soon as patty fixes the link.


I kinda have the same thing going on, every time I hit boost it makes this fluttering sounds, I have the PG Turbo inlet, COBB SRI, and a Type S BPV. I thought it was just noise of the air going through the TIP because it's stainless steel, but now I am worried that it might be surging and I know that can hurt a turbo.

The sound that you hear while at boost is most likely added noise from the inlet. My problem is when i try to get off boost. I really think the sound you are hearing is normal.


I know the sound you speak of....its just a louder deeper sound of the BOV releasing. i took my car for a ride and duplicated it perfectly.

Yes when it was working it was def louder, but after 3 days it when from being "cool loud" to "WTF why is there a turkey in my engine?"


Is there any chance something got dropped into the turbo with the Inlet install? I find it strange that it ran just fine for a day or so then started surging.

Good Lord, I pray that didn't happen. At this point if something were to have been in there it would have made its way through the whole system several times. I was extremely careful and the only thing that may have gotten in there would be some silicone from the coupler and then only if the turbo or inlet sliced a piece off when i was sliding it in place., which would be very, very hard to do. I made sure to make sure there was no debris in the inlet before I installed it.

[mazdaspeed32007]

hmmmm...have you tried to take off the inlet and revert back to stock to see if there is still any noise?

[schmitty]

hmmmm...have you tried to take off the inlet and revert back to stock to see if there is still any noise?

That will be the next step after I test the BPV, with this "pent-test" Patty spoke of.

[mazdaspeed32007]

right....let us know. im interested in what i should do if this ever happens to me.

[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!