Can someone tell me what this part is for? Someone duct taped it.

[kevboost7]

Was removing my front bumper to install a new lip and found someone duct tapped this thing. I'm not sure what its for. 

[Piggaz]

Recirc return pipe.

[Duncan]

Can you drop it at my place, I cracked mine.

I guess you have aftermarket/atmo blow off valve(s) or none at all. Pretty lazy just to leave it sitting there though

[kevboost7]

12 minutes ago, Duncan said:

Can you drop it at my place, I cracked mine.

I guess you have aftermarket/atmo blow off valve(s) or none at all. Pretty lazy just to leave it sitting there though

If you're saying that i dont need it, then sure, just come to the states and its all yours

but wait how does this thing work? Its actually fine like this? 

[GTSBoy]

The (stock) BOVs live down there, on the intercooler return pipe. That pipe there is the return that goes back across to the other side of the engine bay to return the air to the turbo inlets.

[Duncan]

...so, having that pipe there is no real issue as you can't have BOVs that return to the intake any more. 

you should however check what is at the other end of the pipe, from factory it joins into the intake just after the airbox and before the turbs. Duct tape won't stop a boost leak so hopefully both ends of it are disconnected and the intake port is properly sealed off

[GTSBoy]

24 minutes ago, Duncan said:

Duct tape won't stop a boost leak so hopefully both ends of it are disconnected and the intake port is properly sealed off

Yeah, but it's connected to the atmo side of the turbos, so there's no boost to leak. It's just a big, lazy cludge.

[kevboost7]

17 hours ago, Duncan said:

...so, having that pipe there is no real issue as you can't have BOVs that return to the intake any more. 

you should however check what is at the other end of the pipe, from factory it joins into the intake just after the airbox and before the turbs. Duct tape won't stop a boost leak so hopefully both ends of it are disconnected and the intake port is properly sealed off

The other end of that pipe looks like it connects to the intake after the air filter. It connects into one of the pipes with a Y connection. 

Am i okay keeping it like this?

[Duncan]

No, it's really not OK. Like GTSBoy said it is before the turbos but there is still significant vacuum there under boost.

You need to disconnect the other end and properly plug the intake with "something" correctly sized and a decent host clamp.

And since that part wasn't done right you should check how everything was disconnected at the end you took the pic of too. Do you have any BOVs or are those ports blocked off? Is there a loose vacuum line there anywhere?

[kevboost7]

@Duncan hey man, i'd like to revisit this. I do have BOV's. They are blitz. It looks aftermarket. I also traced the other end and it goes straight into both of the turbo side air intakes. Its not disconnected or capped off. So this is basically a big vacuum chamber. 

[Dose Pipe Sutututu]

I would rip that return pipe off, and cap it nicely.

And then wrap it up, send it to @Duncan

 

[GTSBoy]

1 hour ago, kevboost7 said:

So this is basically a big vacuum chamber.

Well, a big chamber at whatever pressure the turbo inlet duct is at, which can be anywhere from atmospheric to a moderate level of suction. Remember, you do not want low pressure between your air filter and your turbo because that is stretching out the air available for the turbo to ingest. Any lower pressure than atmospheric at the turbo inlet works against the pressure ratio that the turbo is able to create. PR2 when you start at 14.7 psi is >29 psi (absolute), which is a whole 14.7 psi of boost. PR2 when you start at only 13 psi is suddenly only 26 psi (absolute). Subtract the 14.7 psi of the outside air from that and you only have 11.3 psi of boost.

[Duncan]

So Dose is right, please send it over, I'd love one that hadn't had a coming together with the australian bush.

Duct tape can't be holding boost pressure so there is more to this story. Is the last pic you took on the right (BOV) or left side of the car looking forward? The left side of the pipe joins into the intake under the airbox standard, I think it is probably capped there too other wise that tape would be blown out.

[kevboost7]

11 hours ago, Duncan said:

So Dose is right, please send it over, I'd love one that hadn't had a coming together with the australian bush.

Duct tape can't be holding boost pressure so there is more to this story. Is the last pic you took on the right (BOV) or left side of the car looking forward? The left side of the pipe joins into the intake under the airbox standard, I think it is probably capped there too other wise that tape would be blown out.

Ha ha, will i ever need this part again? i am actually considering shipping it to you. You guys have been so helpful to me.

 The last picture i took: if you are standing outside of the car looking at the front bumper, then it is on the left side. It is right next to both of the BOV's. 

I think from the factory there was another tube that connected the duct tape part to the BOV's. 

[kevboost7]

One other issue, is my BOV is spitting out oil onto the inside of the bumper. What could that indicate?

[kevboost7]

12 hours ago, Duncan said:

So Dose is right, please send it over, I'd love one that hadn't had a coming together with the australian bush.

Duct tape can't be holding boost pressure so there is more to this story. Is the last pic you took on the right (BOV) or left side of the car looking forward? The left side of the pipe joins into the intake under the airbox standard, I think it is probably capped there too other wise that tape would be blown out.

It is not capped off on the other side. I checked. I also knocked on the duct tape with my knuckles and it is actually really solid. I think its holding boost 🤣

[GTSBoy]

7 hours ago, kevboost7 said:

One other issue, is my BOV is spitting out oil onto the inside of the bumper. What could that indicate?

Normal. There's always oil in the intake tract. Comes from blowby, ando/or turbo seals. Not desirable, but normal.

7 hours ago, kevboost7 said:

I think its holding boost 🤣

THERE IS NO BOOST THERE!

[Duncan]

So, your Blitz blow off valves release air to atmosphere (you can see the trumpet shape) who maximum duck noises. If you are happy with the how the car runs then no need to change anything, but they can cause stalling when returning to idle for example because air that went past the AFM never makes it to the engine.

Same goes, if there is nothing wrong with how it runs you could leave the BOV return in place and taped off, but I think it is trouble (or future trouble). The correct way to cap it off is a proper rubber or silicone cap with a hose clamp right back where it joins the intake and remove everything else.

Correct, the factory BOVs have outlets that connect to that pipe and send air back to the inlet when they pop open, so no metered air is lost. 

Again, in the factory setup the cam cover breathers are connected to the inlet near the airbox. As the engine gets tired it will breathe more and more oil back into the intake, which is meant to be sucked into the engine and burned. In practice, over the years, some will collect at the low points in the intake and your BOV is one of those points. Since it looks like your front bar might be off, it would be worth disconnecting at least one side of the lowest intercooler pipes and seeing how much oil has pooled there

[kevboost7]

Thanks, i will check it out tomorrow. What happened to your BOV recirc pipe? Do you really need it? i might be able to pack it up for you. 

[Duncan]

Hahah it's all good, I'll drop by and pick it up next time I'm stateside.

In the Stagea all that is long gone and I don't run a BOV, but in the GTR race car I have to retain standard everything intake wise, including the standard BOVs, recirc pipe, inlet piping etc etc.

Unfortunately the BOV recirc pipe is the lowest point at the front of the car so I've destroyed a few over the years (and they ain't making any more, unless nismo heritage is listening :))