Wastegate opening before BOV issue

[TriniTT]

Hey all, I have an s13 redtop in my 96 s14. I've had this motor in an s13 before as well, and originally it had a VG30DETT recirc valve as my bov. Well, over time I have read posts about the sound it makes when it releases air, and I began to get curious. I decided to install a Blitz DD bov to satisfy my curiosity. Suffice it to say, I'm even more curious now.

Basically, when the boost is let loose, it makes a fluttering sound (which I've come to learn is a form of compressor surge). I tuned the Blitz bov to open at a very light pressure.

Here is when my issue comes into light: the first thing to happen is the wastegate opens. I know it's the wastegate, because under heavy WOT, the bov will open and it's quite loud. However, under normal, average driving, the wastegate pops open and makes a loud fluttering sound, but the bov doesn't do anything.

I'm running stock boost, stock t25, stock wastegate and actuator, stock everything. I have no exhaust leaks anywhere, my gaskets are all good, esp. around the turbo. My wastegate vacuum line is coming from the lower left nipple on the intake manifold, and the bov is coming from the top right nipple. I even adjusted the wastegate actuator by turning the arm inward more, so I had to pull the actuator arm out hard to get it to reach to the wastegate arm.

Any help and input would be greatly appreciated. Also, I know a recirc is preferred, and once I figure this out I'll recirc this valve again; but for now, I need the noise to be loud so I can diagnose the problem best. Thanks!

[mptjimmy]

idealy wastegate source should be off the turbo compressor side, pre tb

[TriniTT]

idealy wastegate source should be off the turbo compressor side, pre tb

I know, but it's not. It's still pre-tb, as that lower nipple comes before the tb. Still not the source of my issue, as other sr cars I've seen have used this source without the same issues I'm having.

[g6civcx]

Basically, when the boost is let loose, it makes a fluttering sound (which I've come to learn is a form of compressor surge). I tuned the Blitz bov to open at a very light pressure.

Here is when my issue comes into light: the first thing to happen is the wastegate opens. I know it's the wastegate, because under heavy WOT, the bov will open and it's quite loud. However, under normal, average driving, the wastegate pops open and makes a loud fluttering sound, but the bov doesn't do anything.

You need a boost gauge. Your instinct is unreliable, even for seasoned "tuners".

My wastegate vacuum line is coming from the lower left nipple on the intake manifold

It's still pre-tb, as that lower nipple comes before the tb. Still not the source of my issue, as other sr cars I've seen have used this source without the same issues I'm having.

I don't know what's going on here.


I even adjusted the wastegate actuator by turning the arm inward more, so I had to pull the actuator arm out hard to get it to reach to the wastegate arm.

?

I need the noise to be loud so I can diagnose the problem best. Thanks!

Boost gauge. Forget the noise.

[s14unimog]

You have confidently written things that don't make any sense. For one, the Wastegate is used to regulate boost and is not the culprit for the fluttering compressor surge noise. The second thing to note is that the actuator needs a BOOST only source, so its incorrect to say you have a vacuum line running to the throttle body. I would attempt to source a closer boost source rather than run it across the engine bay. You haven't clearly stated your problem here...

Are you asking how you can eliminate the compressor surge?

BTW your title doesn't make sense... "Wastegate opens before bov"....good, it should.

[TriniTT]

Boost gauge. Forget the noise.

I have a boost gauge, it's reading 8psi at wot.

[TriniTT]

You have confidently written things that don't make any sense. For one, the Wastegate is used to regulate boost and is not the culprit for the fluttering compressor surge noise. The second thing to note is that the actuator needs a BOOST only source, so its incorrect to say you have a vacuum line running to the throttle body. I would attempt to source a closer boost source rather than run it across the engine bay. You haven't clearly stated your problem here...

Are you asking how you can eliminate the compressor surge?

BTW your title doesn't make sense... "Wastegate opens before bov"....good, it should.

I understand the working of a turbo system, but thanks for the lesson.

The lower nipple on the tb is before the butterfly, and thus is a boost-only source. When the butterfly closes, the lower nipple isn't open to the intake manifold; only the boost side of the tb. The only issue with its reliability has been discussed often, and is an issue with how long it takes the boost to pressurize a longer vacuum line vs. a shorter one, thus why people recommend putting a nipple closer to the turbo outlet vs. the cold pipe side or the nipple mine is connected to. Really, it's a small issue altogether, and my source for the wastegate works just fine.

Also, I wasn't insinuating my wastegate actuator was causing compressor surge. The cause of the sound is the compressor, but the pathway through which the sound travels is through the wastegate.

To clarify my problem, the BOV isn't opening under light throttle; only the wastegate is opening. Is this what should be happening? I.e., should the BOV only open under wot and full boost? I thought the two worked together and opened together to let boost out? Or does the BOV only open when there's enough boost to open it after the wastegate actuator opens?

[DRFTWHORE]

stock boost is 7 on sr, so it takes 7psi of boost to open the wastegate, when u let of throttle on low rpms ur bov wont make noise because ur wastegate never opens all the way to boost so the blow off valve will not make noise cuz it never boosted end of story

[Ceepo]

I run my vacuum lines like this with no problems...

2 nipples above the throttle body-
one on left goes to my fuel pressure regulator/tee'd off to boost/vac gauge
one on the right(larger one) goes to my bov

1nipple under the throttle body-
Goes to my wastegate(till i can get a nipple welded on my hotpipe)

Ideally everyone says run the hose to the wastegate as close to the turbo as possible, but i dont see a real problem running it from the nipple under the tb other then the tubing being long... I have also heard people say that teeing off the fuel pressure regulator for my boost/vac gauge is a bad idea but i havent had one issue with it...

[g6civcx]

people say that teeing off the fuel pressure regulator for my boost/vac gauge is a bad idea but i havent had one issue with it...

I have never had an issue with this. Who says?

[jspaeth]

I'm really confused.

Where is there a Nipple on the SR near the TB/Intake Mani that is PRE-THROTTLE BODY?

This is retarded.

Run vacuum line from hotpipe to wastegate.

Run vacuum line from manifold nipple to BOV

Done.

[jspaeth]

I have never had an issue with this. Who says?


I run the FPR and BOV T-ed off of one vacuum nipple and each of my 2 MAP sensors T-ed off of a second.

Never have any problems.

And before anyone asks why 2 MAP sensors, it's bc one is for Power-FC, the other for AVC-R.

[g6civcx]

I run the FPR and BOV T-ed off of one vacuum nipple

Never have any problems.


Really? Why does everyone make such a big deal about the BOV being on its own line?

[jspaeth]

Really? Why does everyone make such a big deal about the BOV being on its own line?

I have no idea.

The BOV is not a precision instrument. If the pressure to it is off by a psi or 2, who gives a fuck.

The MAP sensors are, however. Ideally, I'd like to have them each on their own separate vacuum nipples, along with the FPR on its own, but right now I only have 2 ports.

I don't think this is a huge deal, honestly.

I have one long hose running from one nipple that splits off into 2 short 3 inch ones, each going to one of the MAP sensors.


My AVC-R MAP sensor reads like 0.5-1 psi (20-40 mmHg) higher than the PowerFC one, but this is presumably a calibration/offset thing with the voltage.

[TriniTT]

DRFTWHORE: thanks for the info, that makes a lot of sense.

jspaeth: The nipple was originally intended for the canister, and didn't need to have vacuum pressure, just boost pressure. I find nothing retarded about the fact that Nissan conveniently (albeit unintentionally) left us a great source for the wastegate actuator pressure, especially since so many hotpipe kits don't include a nipple, and there are plenty of people who aren't very fabrication-inclined. Regardless of the discussions about its reliability as a wastegate source, it works great and there haven't been any serious issues reported from using it.

Also, the issue with tee-ing off the fpr with the bov is simply that most people don't want to have the fpr pressure source tee-ed with anything else simply for reliability. I.e., the more vacuum lines that are tee-ed and run, the higher the chances of something to leak and thus, the lowered reliability for the fpr to function properly. It basically boils down to personal preference. Personally, I don't like having anything connected to my fpr source, but it won't really hurt anything as long as there aren't any leaks.

[jspaeth]

DRFTWHORE: thanks for the info, that makes a lot of sense.

jspaeth: The nipple was originally intended for the canister, and didn't need to have vacuum pressure, just boost pressure. I find nothing retarded about the fact that Nissan conveniently (albeit unintentionally) left us a great source for the wastegate actuator pressure, especially since so many hotpipe kits don't include a nipple, and there are plenty of people who aren't very fabrication-inclined. Regardless of the discussions about its reliability as a wastegate source, it works great and there haven't been any serious issues reported from using it.

Also, the issue with tee-ing off the fpr with the bov is simply that most people don't want to have the fpr pressure source tee-ed with anything else simply for reliability. I.e., the more vacuum lines that are tee-ed and run, the higher the chances of something to leak and thus, the lowered reliability for the fpr to function properly. It basically boils down to personal preference. Personally, I don't like having anything connected to my fpr source, but it won't really hurt anything as long as there aren't any leaks.

Agreed.

As long as you are 100% certain the nipple is pre-throttle body, you are okay, but it really would be best for it to be as close to the turbo as possible.

Btw what kind of boost control are you running, if any?

[ges311]

Have you checked to make sure the bov is internally ok? Was this brand new or purchased used? I am not familiar with the blitz bov, but sometimes the diaphragms rip, especially on the greddy ones.

[TriniTT]

Have you checked to make sure the bov is internally ok? Was this brand new or purchased used? I am not familiar with the blitz bov, but sometimes the diaphragms rip, especially on the greddy ones.

It was used; I may borrow a buddy's car and throw it on to see how it work. The thing is, it works fine, but only when it's close to 7psi, but not when it's any less.

And I'm not running any boost control right now, just the stock wastegate.

[s14unimog]

Also, I wasn't insinuating my wastegate actuator was causing compressor surge. The cause of the sound is the compressor, but the pathway through which the sound travels is through the wastegate.

Incorrect. The sound is not audiable through the wastegate. the wastegate is merely a door on the exhaust side of the turbo, used to regulate pressure output. If you hear compressor surge, its likely that the sound is coming from the BOV its self, you are hearing it through piping, or through the intake

To clarify my problem, the BOV isn't opening under light throttle; only the wastegate is opening. the waste gate will not open until the actuator sees the amount of boost required to open it. Is this what should be happening? I.e., should the BOV only open under wot and full boost? the BOV should only open under vacuum in the IMI thought the two worked together and opened together to let boost out? incorrect, the wastegate is used to regulate pressure output. The BOV is used to evacuate excess boost pressure while the TB is closed.Or does the BOV only open when there's enough boost to open it after the wastegate actuator opens?

You need to understand that they are not related by any means. But I forgot, you understand how a turbo system works.

I understand the working of a turbo system, but thanks for the lesson.

[jspaeth]

^ What s14unimog said is right.

This thread sucks balls.

[g6civcx]

I understand the working of a turbo system

This statement does not agree with these statements.

the pathway through which the sound travels is through the wastegate

I thought the two worked together and opened together to let boost out?

Or does the BOV only open when there's enough boost to open it after the wastegate actuator opens?

It seems like you think you know what you're doing while at the same time not being able to diagnose a simple problem.

I don't think I can help you at this point either. Good luck.

[s14unimog]

It's too late for him guys... We're going to have to pull out!

[jspaeth]

hahahah i love and hate this thread simultaneously.

[TriniTT]

You need to understand that they are not related by any means. But I forgot, you understand how a turbo system works.

It's too late for him guys... We're going to have to pull out!

Nice inferiority complex. I'd put that on ice for a little while if I were you.

Really? Why does everyone make such a big deal about the BOV being on its own line?

If we're going to make this post about marring credibility, let's just point out the fact that you completely missed the ballpark about why it's recommended not to have anything on the same line as the fpr.

Just to make sure I've got this, and since you're all so convinced I don't, the wastegate is a door that opens to let pressure out so as not to overboost the engine, and opens via the actuator at the preset amount dictated by the vacuum pressure it receives from the boost side of the tb. (I think the fact that you didn't know the lower nipple under the tb is boost-only shows you're not as bright as your inferiority complex would insinuate, but at this point that's all moot). I learned turbo systems on the VGTT, so I'm used to everything being in twos on a much larger engine, so pardon my ignorance of the noises that are going on and the fact that they're different from what I'm used to hearing.

The BOV opens to let boost pressure out of the boost side of the intake system (when the tb closes and the turbo is still charged) and is dictated by the vacuum from the manifold. I get all this, so don't pin me as a moron and ctfo for a minute to try to understand the issue I'm having.

I've had a stock recirculation valve on this, and I was hearing the same sounds with that vs. the blitz bov at less than full boost. Basically, if I get 7-8psi on my boost gauge, the bov opens, but if it's anything less than that, my bov doesn't open. Is the boost pressure too high at that point for it to not be opening, or is anything less going to be an issue if there isn't a valve to open it? (i.e. is it going to affect the turbo or anything else for there not being a boost-side outlet at 6psi?) I thought that the bov should open even at a lower boost level to let boost out, even if it's not as high as 7psi. The only sound I'm hearing happens when the wastegage opens to let pressure out, but not when the BOV opens. This is my issue. It doesn't happen any other time than when only the wastegate opens.

Oh also, you're both wrong about the fact that the BOV and wastegate don't work together. They each have individual functions, but they both work together to prevent overboost.



On a heavier note, helping someone diagnose a problem is as simple as being an adult about it. Repeatedly trying to hammer a point that someone is an idiot and has no idea what they're talking about doesn't help anyone (besides feeding your previously addressed inferiority complex), and the tech forum really isn't the place for sarcasm. Plus, it's just bad karma.

Just because you can't understand what I'm trying to say doesn't mean I'm the idiot; I cannot control your lack of comprehension, I can only describe to the best of my ability, which I have.

[g6civcx]

If we're going to make this post about marring credibility, let's just point out the fact that you completely missed the ballpark about why it's recommended not to have anything on the same line as the fpr.

My comment was directed towards the BOV, not the FPR.

I also do not claim to know anything. I am the dumbest person ever lived. I'm only good at pointing out things that don't make sense.

If you're going to grasp at straws, at least make an effort.


Just to make sure I've got this, and since you're all so convinced I don't, the wastegate is a door that opens to let pressure out so as not to overboost the engine, and opens via the actuator at the preset amount dictated by the vacuum pressure it receives from the boost side of the tb.

Everything between the turbo and the intake valve sees boost and may be considered the "boost side". Then both sides of the TB are the "boost side".

Oh also, you're both wrong about the fact that the BOV and wastegate don't work together. They each have individual functions, but they both work together to prevent overboost.

The wastegate stops the exhaust stream from spinning the turbine. The CBV/BOV vents the charged pipe. Since the TB is closed when the BOV opens, what does boost have to do with anything?

On a heavier note, helping someone diagnose a problem is as simple as being an adult about it. Repeatedly trying to hammer a point that someone is an idiot and has no idea what they're talking about doesn't help anyone (besides feeding your previously addressed inferiority complex), and the tech forum really isn't the place for sarcasm. Plus, it's just bad karma.

You're the one accusing people of having mental problems. I'm just saying that you said you know, then you ask questions like you don't know. Then you get upset when I point out that what you're saying doesn't make sense.

Just because you can't understand what I'm trying to say doesn't mean I'm the idiot; I cannot control your lack of comprehension, I can only describe to the best of my ability, which I have.

Your ability is not enough. You need to either be humble and accept the help, or be arrogant/condescending and don't ask for any help. You can't have both.

I was actually going to try to help you up until the point where you claim to know how a turbo works, but then say the things I quoted above. Now I'm definitely staying out of here.

Stop asking questions since you already know how a turbo works on a bigger engine.

[jspaeth]

If we're going to make this post about marring credibility, let's just point out the fact that you completely missed the ballpark about why it's recommended not to have anything on the same line as the fpr.

(I think the fact that you didn't know the lower nipple under the tb is boost-only shows you're not as bright as your inferiority complex would insinuate, but at this point that's all moot).

The BOV opens to let boost pressure out of the boost side of the intake system (when the tb closes and the turbo is still charged) and is dictated by the vacuum from the manifold. I get all this, so don't pin me as a moron and ctfo for a minute to try to understand the issue I'm having.

I've had a stock recirculation valve on this, and I was hearing the same sounds with that vs. the blitz bov at less than full boost. Basically, if I get 7-8psi on my boost gauge, the bov opens, but if it's anything less than that, my bov doesn't open. Is the boost pressure too high at that point for it to not be opening, or is anything less going to be an issue if there isn't a valve to open it? (i.e. is it going to affect the turbo or anything else for there not being a boost-side outlet at 6psi?) I thought that the bov should open even at a lower boost level to let boost out, even if it's not as high as 7psi. The only sound I'm hearing happens when the wastegage opens to let pressure out, but not when the BOV opens. This is my issue. It doesn't happen any other time than when only the wastegate opens.

Oh also, you're both wrong about the fact that the BOV and wastegate don't work together. They each have individual functions, but they both work together to prevent overboost.


1) Putting FPR on it's own line is a good idea solely for the fact that a leak somewhere else wouldn't fuck it up. Otherwise, without leaks, having vacuum lines connected to other things (MAP sensors, for example) will have no noticeable effect.

2) I don't have a nipple under my throttle body, and I thought you were referring to the ones on the intake manifold, which in some sense are located "under the throttle body"

3) Okay, good you understand how the BOV works (but not the wastegate, it seems)

4) The BOV and wastegate do NOT work TOGETHER to limit boost pressure. This is the sole role of the wastegate. Under boosting conditions, the BOV is always completely shut.

When you let off the throttle while boosting, the built up boost pressure is released throught the BOV to prevent the pressure wave from running back into the compressor (surge).

This is not "limiting the boost" as you say. The BOV has NO role in limiting boost pressure. It does not work "together" with the wastegate.

5) Finally, the BOV is not just an on/off device. At intermediate levels of boost pressure/throttle let-off, it can flutter, or not open all the way, leading to mild compressor surge.

It is not really possible to completely eliminate compressor surge without having the BOV open to easily while driving around. The best thing to do is to tighten it so that is stays closed under normal driving and blows off (for example) if you build 5+ psi and then let off the throttle.

As a result, you may hear minor compressor surge if you build less boost and then let off the throttle, and it's probably not enough to hurt your turbo.

[S14DB]

Nice inferiority complex. I'd put that on ice for a little while if I were you.



If we're going to make this post about marring credibility, let's just point out the fact that you completely missed the ballpark about why it's recommended not to have anything on the same line as the fpr.

Just to make sure I've got this, and since you're all so convinced I don't, the wastegate is a door that opens to let pressure out so as not to overboost the engine, and opens via the actuator at the preset amount dictated by the vacuum pressure it receives from the boost side of the tb. (I think the fact that you didn't know the lower nipple under the tb is boost-only shows you're not as bright as your inferiority complex would insinuate, but at this point that's all moot). I learned turbo systems on the VGTT, so I'm used to everything being in twos on a much larger engine, so pardon my ignorance of the noises that are going on and the fact that they're different from what I'm used to hearing.

The BOV opens to let boost pressure out of the boost side of the intake system (when the tb closes and the turbo is still charged) and is dictated by the vacuum from the manifold. I get all this, so don't pin me as a moron and ctfo for a minute to try to understand the issue I'm having.

I've had a stock recirculation valve on this, and I was hearing the same sounds with that vs. the blitz bov at less than full boost. Basically, if I get 7-8psi on my boost gauge, the bov opens, but if it's anything less than that, my bov doesn't open. Is the boost pressure too high at that point for it to not be opening, or is anything less going to be an issue if there isn't a valve to open it? (i.e. is it going to affect the turbo or anything else for there not being a boost-side outlet at 6psi?) I thought that the bov should open even at a lower boost level to let boost out, even if it's not as high as 7psi. The only sound I'm hearing happens when the wastegage opens to let pressure out, but not when the BOV opens. This is my issue. It doesn't happen any other time than when only the wastegate opens.

Oh also, you're both wrong about the fact that the BOV and wastegate don't work together. They each have individual functions, but they both work together to prevent overboost.



On a heavier note, helping someone diagnose a problem is as simple as being an adult about it. Repeatedly trying to hammer a point that someone is an idiot and has no idea what they're talking about doesn't help anyone (besides feeding your previously addressed inferiority complex), and the tech forum really isn't the place for sarcasm. Plus, it's just bad karma.

Just because you can't understand what I'm trying to say doesn't mean I'm the idiot; I cannot control your lack of comprehension, I can only describe to the best of my ability, which I have.
You have no clue what you are talking about.

Blow off Valve will not prevent you from overboosting. It is to prevent compressor surge. It will only open up when there is a differential in pressure between the intake manifold and the charge pipes.

Wastegate does not bleed off boost pressure. It allows exhaust gases to bypass the turbine wheel reducing it's potential energy. it is boost controlled.

Please don't confuse your ignorance with knowledge. People are/were trying to help you.

[g6civcx]

Please don't confuse your ignorance with knowledge. People are/were trying to help you.

Probably the most accurate statement in this whole thread :bigok:

[TriniTT]

My comment was directed towards the BOV, not the FPR.

I also do not claim to know anything. I am the dumbest person ever lived. I'm only good at pointing out things that don't make sense.

If you're going to grasp at straws, at least make an effort.


Everything between the turbo and the intake valve sees boost and may be considered the "boost side". Then both sides of the TB are the "boost side".

Boost side of the TB, meaning the side that sees boost all the time. It's a common understanding what "boost side" means. When the tb is closed, nothing else sees boost past it, including the intake valves.

The wastegate stops the exhaust stream from spinning the turbine. The CBV/BOV vents the charged pipe. Since the TB is closed when the BOV opens, what does boost have to do with anything?

Are you serious? It's letting boost out, it has EVERYTHING to do with boost!

You're the one accusing people of having mental problems. I'm just saying that you said you know, then you ask questions like you don't know. Then you get upset when I point out that what you're saying doesn't make sense.

Your ability is not enough. You need to either be humble and accept the help, or be arrogant/condescending and don't ask for any help. You can't have both.

You can't force someone to be humble. I came in here asking a question humbly, but some of you tried even harder to force me into an even lower position than I'd where I'd started. If you'd simply tried to help and gain a better understanding without trying to make me feel like a moron, it would have gone much more smoothly. Instead, you all acted like assholes.

[S14DB]

Boost side of the TB, meaning the side that sees boost all the time. It's a common understanding what "boost side" means. When the tb is closed, nothing else sees boost past it, including the intake valves.



Are you serious? It's letting boost out, it has EVERYTHING to do with boost!



You can't force someone to be humble. I came in here asking a question humbly, but some of you tried even harder to force me into an even lower position than I'd where I'd started. If you'd simply tried to help and gain a better understanding without trying to make me feel like a moron, it would have gone much more smoothly. Instead, you all acted like assholes.

Way to take the humble pie.

Wastegate - Wikipedia, the free encyclopedia (http://en.wikipedia.org/wiki/Wastegate)
Blowoff valve - Wikipedia, the free encyclopedia (http://en.wikipedia.org/wiki/Blowoff_valve)

[g6civcx]

Some real help for once.

Plumb the BOV/CBV and wastegate as close to the factory setup as possible. Get everything working as well as possible.

Then you mod one thing at a time.

Randomly moving multiple boost sources and expect things to work out well is not the right way.

[codyace]

"It's what you learn after you know it all that counts. ~Harry S. Truman"

Listen to what some of these OG's are trying to tell you, instead of pretending to know. It's obvious you are either confused at what the parts operation is, or can't determine what each sound is that your car is making.

I'm willing to bet your car is working fine...


And in regard to the blow off valve and the wastegate working to prevent boost....you're very wrong. Don't confuse the blow off valve with a pop off valve (such as those found on Ford S/C cars).