Stock BPV question

[CTSpd6]

At what point is the stock BPV not able to hold boost. I recently flashed the Stage 1+SF 93 map and i did a couple WOT pulls. When i got to around peak boost, i would hear this high pitch noise like an air horn. I only hear it when i'm WOT and at/near peak boost and that's why i'm thinking its the stock BPV. How much boost can it handle?

[WorstEpEver]

Since you have AP, do some logs at WOT. You will be able to see if it's holding boost or not.

If you hear a whoosh go off before you lift, it probably is the stock bpv however.

[rfinkle2]

Originally Posted by CTSpd6 At what point is the stock BPV not able to hold boost. I recently flashed the Stage 1+SF 93 map and i did a couple WOT pulls. When i got to around peak boost, i would hear this high pitch noise like an air horn. I only hear it when i'm WOT and at/near peak boost and that's why i'm thinking its the stock BPV. How much boost can it handle?

That sounds like a boost leak for sure, although some logs might help as worst ep said.

Some stock bpvs leak, others don't.

If you can do a boost leak test, you will be able to get an idea what the noise is / coming from a little better.

[Broxer]

My stocker has been able to hold 20psi without an issue. A high pitched noise could be a boost leak, not necessarily from the BPV.

The only issue I've had with my stock unit is that it opens during partial throttle during slow acceleration.

[ZsSpeed3]

I'm using the stocker right now, no issues for me and reaching 15psi yesterday.

Edit: not pushing

[Nazarite]

@ZsSpeed3 then you've got a problem because stock you should be at 15.4. @Broxer I'm spiking 21 and holding 19 on the stock bpv as well. @CTSpd6 everyone's is different like these guys are saying. Some hold, some don't, only your logs can tell you what your case is.

[helmetface]

Originally Posted by ZsSpeed3 I'm using the stocker right now, no issues for me and I was pushing it to 15psi yesterday.

Pushing it to 15psi lol

All in all, as others have mentioned, some stockers hold incredibly adequate while others take a face plant..

With that said, you need a monitoring device, go through all your piping and make sure everything is tight. While all the signs lead to a boost leak, that doesn't necessarily mean its a BPV leak.

Good Luck

[ZsSpeed3]

I am using my DH to monitor and I haven't upgraded my turbo or anything. It was in the 15's almost 16, just didn't want to say something that made wasn't true. So.....wasn't "pushing" it, that's what it was holding till I let off the pedal.

[CTSpd6]

Thanks for the responses. I will do some logs after work.

[Nazarite]

Originally Posted by ZsSpeed3 I am using my DH to monitor and I haven't upgraded my turbo or anything. It was in the 15's almost 16, just didn't want to say something that made wasn't true. So.....wasn't "pushing" it, that's what it was holding till I let off the pedal.

Hey man, we're just messing with you because you're talking about holding stock pressure while the guy right above you said he pushed it 5 psi more. Surely you see the irony. But hey, at least you're holding stock psi, some guys bpv's can't do that.

[CTSpd6]

Originally Posted by helmetface00 Pushing it to 15psi lol All in all, as others have mentioned, some stockers hold incredibly adequate while others take a face plant.. With that said, you need a monitoring device, go through all your piping and make sure everything is tight. While all the signs lead to a boost leak, that doesn't necessarily mean its a BPV leak. Good Luck

With a boost leak, is it normal that i'm only hearing this noise at WOT near peak boost? I would think that i would hear it more often than that.

[rfinkle2]

Originally Posted by CTSpd6 With a boost leak, is it normal that i'm only hearing this noise at WOT near peak boost? I would think that i would hear it more often than that.

The more pressure you put on a loose connection, the more likely you are to hear it.

If it sounds like someone is blowing through a blade of grass, or pinching a balloon opening and letting the air squeal out, it is probably a silicone coupler vibrating against a hard pipe.

Boost leaks are almost impossible to diagnose from in the car while driving.

[FORZDA 1]

My OEM BPV worked perfectly at 21psi, but definitely began leaking at 23. If you look at the design, I believe that Mazda intended it to leak at higher (21psi+) boost levels....

[BlueStreak]

I am currently running 22.5PSI with no leaks.

I have also successfully boost leak tested the BPV to values higher than that (remove return hose, plug TIP connection to return hose and pressurize system).

[helmetface]

Originally Posted by rfinkle2 Boost leaks are almost impossible to diagnose from in the car while driving.

Boy do I know this one haha

@ZsSpeed3 - Ya I was only giving you flak because thats the ~pressure the stockers was meant to run at, give or take.

[ZsSpeed3]

Whateva.... tampon has been removed. ha ha

[pinggoy]

if you have a DH boost/vac should be around -21.00.. i might be wrong.

[ZsSpeed3]

My DH is messed up, missing a whole bunch of PID's. Won't let me do the Boost/Vac, just Boost PSI. Dumb thing, need a PC to update. all i have is a Mac.

[pinggoy]

can you not update it? there is a download somewhere on this site for DH.

[phate]

You can tweak the stock BPV so it holds whatever you throw at it. Takes about 5 minutes and may not cost you anything. TRex posted my writeup here before I was a member, called something like "stock BPV leak? I may have a cost effective semi-solution". I've been running it for ~20k miles without a problem.

[Lex]

Originally Posted by phate You can tweak the stock BPV so it holds whatever you throw at it. Takes about 5 minutes and may not cost you anything. TRex posted my writeup here before I was a member, called something like "stock BPV leak? I may have a cost effective semi-solution". I've been running it for ~20k miles without a problem.

Read your post in that thread - so is the flange leaking to atmosphere thus allowing metered air to escape or is the boost leaking into the bottom chambers and out into the intake?

If leaking to atmosphere could it not be epoxied?

Most aftermarket BPVs cause flutter - the HKS and pull type BPVs are well known for this. A little surge at LOW boost pressures is not bad - surge at high boost pressures starts to load the turbo shaft.

[LuczOr]

My stock valve was holding great at stock boost levels.

[Blackspeed]

Originally Posted by ZsSpeed3 My DH is messed up, missing a whole bunch of PID's. Won't let me do the Boost/Vac, just Boost PSI. Dumb thing, need a PC to update. all i have is a Mac.

I had that happen to me and I just unplugged it from the OBD port and plugged it back in.

[FORZDA 1]

Originally Posted by phate You can tweak the stock BPV so it holds whatever you throw at it. Takes about 5 minutes and may not cost you anything. TRex posted my writeup here before I was a member, called something like "stock BPV leak? I may have a cost effective semi-solution". I've been running it for ~20k miles without a problem.

Yep, but it isn't "tunable" it's either stock or whatever(?) the spring will hold.

[phate]

Originally Posted by Lex Read your post in that thread - so is the flange leaking to atmosphere thus allowing metered air to escape or is the boost leaking into the bottom chambers and out into the intake? If leaking to atmosphere could it not be epoxied? Most aftermarket BPVs cause flutter - the HKS and pull type BPVs are well known for this. A little surge at LOW boost pressures is not bad - surge at high boost pressures starts to load the turbo shaft.

Yes, the flange leaks to atmosphere. It's such a miniscule amount, I doubt it affects the tune. I think it does, however, affect the BPV operation. Epoxying the flange is a possible fix, but I haven't really done anything with it since I wrote that post. The car runs extremely well, even with the flange leaking slightly.

I've heard the flutter argument about shaft loading, but I've never seen any proof of this happening. Where surge does have an effect is at WOT/fully loaded. Yes, in that case, turbos sometimes explode.

The converse argument for flutter is that it prevents a possible overrun situation. Meaning there is zero restriction on the turbo outlet while the BPV/BOV is open, where the turbo can spin as fast as possible.

I'm not saying either is correct, because I don't have direct empirical evidence supporting either theory. I do, however, know of many turbo cars that have fluttered for thousands upon thousands of miles without a problem.

[blackspeed223]

Originally Posted by Broxer My stocker has been able to hold 20psi without an issue. A high pitched noise could be a boost leak, not necessarily from the BPV. The only issue I've had with my stock unit is that it opens during partial throttle during slow acceleration.

Sry to bring up an old post but i saw this because im having the same problem and was wondering what you did to fix it. if you could help me out that would be awesome if not ill keep searching. thanks

[Lex]

Is your problem a boost leak? If so locate it using a boost leak test

Is the issue the BPV opening at part throttle? This is absolutely normal. If you want to VTA your OEM BPV you need to use the Guardian Angel which keeps it closed.

[blackspeed223]

I don't think it's a boost leak I just have the problem of where the bpv is opening up when just cruising up to speed at about 3 grand. All my numbers are good atf is 14.7 at idle 11.6 at wot. FP is round 430 at idle and between 1650-1750 at wot.

[blackspeed223]

ok i have searched high and low and this is the only one that i have found but still no answer... i did the same tune as the OP and i have the same problem w the BPV blowing off in slow acceleration before i even take my foot off the pedal. just wondering if this is a problem or not. I dont suspect boost leak seeing as how it holds boost at high RMP.

[Lex]

How do you know the BPV is flowing off? Can you hear it?

If it's blowing off during acceleration it might be faulty. Try blowing/sucking on the top port. If you can blow through that port the diaphragm is torn inside.

[blackspeed223]

Yes cuz when I was driving I felt it kinda fall and looked at the boost and saw it drop. So I turned down the radio and went through the gears again and before I would get to 3 grand it would blow of and boost would drop