SBD turbo surge??
 

Alright guys i got a question. I just got done installing the SBD turbo kit and took the car out for a drive, here's the order of event.

3krpm
Wot
Turbo spools
Car accelerates
Around 6krpm the bov starts fluttering like crazy while in boost.

Any idea what's causing this?

Are you losing boost? The BOV is just a spring and a vacuum line working against eachother.. is the vacuum line connection solid?

Physically, the lines looks secure. And its not like I'm boosting high, only 7psi.
I Let go of the gas soon as i heard it so I'm not sure if I'm losing boost or not. I'll see if i can recreate three problem when the snow lets up

Are you sure you're talking about the BOV..? The BOV releases pressure in the intake piping. I can't imagine how it would "flutter". If there was something wrong, it would maybe not be shut all the way at idle or not open enough at low boost and cause turbo flutter.. but I can't imagine how it would flutter at WOT.

Are you hearing the turbo spooling and the wastegate maintaining the 7psi? Is the whole turbo thing new to you or is this a recent new problem?

it's the only thing i could think of that's making that noise. it may very well be something else that's causing the noise, but i did double check the lines that runs from the bov to the brakebooster and it looks fine.
i was also able to get a datalog of the even, but it looks like nothings going on.
here's the link the datazap, it happened at around 33s
Yes, happen while in wot. And yes I'm new to the turbo scene.
I'll see if i can get a video recording of it. Maybe that'll help explain it better

http://www.datazap.me/u/shif7i7down9...2&zoom=235-340

Well you let off the throttle at 33s, and up to then your boost was rock solid so it wasn't your BOV. Pretty sure you are just hearing your turbo..

Do you have a way to monitor your actual boost levels, is that the stock MAP sensor? I am assuming you are running more than 5.37psi. Everything looks fine though..

Yeah, the oft seems to top out at 5psi-ish but it's suppose to be a 7.5psi internally Wastegated turbo. And yes I'm running the stock map sensor. Any yes it was going fine until i heard the clinging and Ley off the gas.

Kinda sounds like when you grind your gears

Clinging or fluttering? I'd have to hear the noise..

What I am imagining you are hearing is the turbo makes sort of a fluttering spool noise once it spools and the wastegate tries to maintain X psi. But maybe you are hearing something else.. try to get a video. Whatever it is, it's not your BOV, and I highly doubt it's serious because your log looked normal.

Looking more at your log, not likely related to your noise, but your long term fuel trims are pretty ridiculously high. Who tuned your car?

Okay. I'll try it out again in the morning once they clear the snow off the road

Lol. I was in a hurry to play with the newly installed kit and filed the tank with 93oct while there was still a quarter tank of e85 left . But the tune is from shiv oft

I see, I would try to get as much 93 in there.. Your AFRs seem a little inconsistent.. but nothing that would cause the noise you are talking about.

Ok. But the closes sound i could think of is like when you have a fan running and you run something across the blades, but more of a metallic sound

Metallic? Hmm..

Was that the first pull, or have you gone WOT before without said noise?

That was not the first pull. But it was within the first 15mins of driving and multiple pulls

I bet its an OFT tune. Is this a fresh tune or did you record this log hours later ?

That was the log of when it happened

When you say flutter, do you mean something like this sound? Cause that's what's coming to my head when you say flutter when you let go of gas. [ame="https://www.youtube.com/watch?v=D3djVW3dSGA"]Nissan Skyline GTR R34 Turbo Sound - YouTube[/ame].

What your hearing is the fluttering from the headers when building boost. It is because they are slightly unequal and have flex joints on only two of the four runners. Every kit I have installed or heard has the same noise. It is absolutely nothing to worry about, and you can actually mask it very well by wrapping the headers.

It's a bit different then that video, I'll have to capture it with a camera so that it'll be easier to explain. And its not happening while decelerating only during wot

Still could be what Neal said. You only build boost when accelerating.

here's a video of what i'm talking about.. sounds weird

[ame]http://youtu.be/N6_MOTWKRcA[/ame]

Are you talking about the horrible noise after you left off the gas? IE at 10 seconds? I couldn't tell if it was wind or the end of the world in your engine bay.

When you get on it, it sounds pretty normal.. the 'flutter' at full boost sounds to me like the the turbo/wastegate maintaining __ psi. It's hard to tell much though. Especially in higher gears where there is more exhaust volume trying to spool the turbo, the wastegate will work a little harder and you can hear the turbo n wastegate fluttering so to speak. I'm betting it doesn't do it in 1st gear or maybe 2nd? Mine makes the noise in 4th-6th.. sometimes in 3rd if I get on it from lower in the RPM range and its colder outside.

it sounds like air is being released while i'm boosting, you can hear it kinda like a hissing/popping noise. it starts at around 6 sec, and it does sound like it's the wind, but it's not.. that's the noise i was talking about.. -_-. Im in the car with the windows down.

you can hear it whining up and then it slows down and speeds up again, sounds kinda like a engine trying to crank O_O..

edit: it's the sound that sounds like static

The sound at :06 is wastegate flutter (IDK technical term, but your wastegate is trying to keep your turbo spooled at a specific amount and, especially in higher gears at higher rpm when there is more exhaust volume fighting it, thats the sound it will make)... normal. It's trying to maintain the ~7psi (whatever spring is in there). Looking at your log, you aren't losing boost that is noticeable. If you had a proper sized MAP sensor scaled then you could tell for certain, but what you are hearing is pretty typical.

I'm sure some other guys can verify.. unless there is another sound that I'm just not hearing.

Just for clarification.. the sound at like :15 is the wind buffeting, right?

There's no wind, the window it's closed so I'm not sure that youre referring to. The chattering pulsating sound, which sounds like air is being released it's what i was talking about. It sounds Kinda like tires chirping but it's the coming front the driver side. Of i had to guess it sounds like it's coming from somewhere near the brake booster

He is talking about the sound you are hearing. I don't understand however why the wastegate is trying to regulate boost pressure while you are off the gas.

[ame="http://www.youtube.com/watch?v=Hs2cMA6jKSU"]Wastegate flutter??? - YouTube[/ame]

So you're talking about the sound that starts at like :10? After you let off the gas?

Give us an exact timeframe in the video......

The sound starts at 5sec and continues from there

Dude.. what exact noise?? If it's the one that starts at :10 and gets worse over 10 seconds or so, then that is far far far from normal. I assumed you had the window down and that was the wind If you are talking about the wastegate flutter at :06 then that is normal.

:05 until .......? Because the noise that starts at :05 I only hear for a few seconds and seems normal, and then a completely different noise starts at :10 (which I thought was the wind, but if it's not then you should stop driving the car.)

Window is not down. The noise is allot more noticeable at the 10sec but it starts at like 5-6sec in the video. I'm not sure how to describe it. But it does sound like the video that Mike posted

You're making this impossible to diagnose. What EXACT timeframe are you referring to, and are the windows UP or DOWN?

Who did the install of your turbo?

With my headphones on I hear your BOV going crazy from 0:06-0:26. This is not normal, and why all Turbo applications should have a boost gauge. Somethings wrong, you should have it checked out.

*deleted rest to avoid confusion.

That's not how a BOV works.. and if the BOV was open then there wouldn't be turbo surge. The BOV has a spring that keeps it closed under vacuum. When the throttle closes, the pressure in the intake pipes is higher than the vacuum in the manifold so it pushes it open. Turbo surge would kill the turbo, not really the engine.. unless the turbo completely failed.

That's where I'm confused, it's either the bov or the Wastegate

That doesn't sound like wind fluttering, almost sounds like flapping but I'd be inclined to think there's something wrong with the turbo itself. The BOV is driven off pressure difference between pre-throttle body and manifold pressure. The wastegate is driven off boost pressure. That sound when you let off is very unusual. Nothing should be causing the BOV to flutter though.

It's not the BOV.

Does it happen if you are cruising at higher speeds, not WOT?

Rev it parked, with hood open, and see if you can locate the sound.

If your turbo is fluttering, that is very unhealthy for the system. As we (presumably) all know, flutter is caused when throttle is shut and air is caught between the free-spinning turbine and the closed throttle..