[JoshApple]

Hello all, I was taking off from a red light the other day and noticed severe lack of power and a muffly sound from the exhaust. Upon further review, it sounds like there is a loose connection on the exhaust side of the motor. Sounds like the car is running on open headers….

I have tried to capture the sound on video but not sure how noticeable it will be. Sounds like an old, straight-piped beater car. Downpipe to mid pipe connections are intact. Cannot see turbos enough without dropping subframe to be able to tell what’s going on up there.

Does anybody know what connection or issue could be causing this sound? Did I blow a turbo? Did the Downpipe-turbo clamps come loose? I live in Michigan and we have had very wet, slushy,snowy conditions lately.

video 3 (best)
Video 2
Video 1 (good)

2007 N54 FBO, turbos are Vargas replaced around 30-45k miles ago. 160k miles.

[JoshApple]

Anybody have any ideas?

[Sgop335]

Any codes?
Usually a leak after downpipe shows d/s o2 sensor code and power is not reduced

[JoshApple]

Originally Posted by Sgop335

Any codes?
Usually a leak after downpipe shows d/s o2 sensor code and power is not reduced

These are the only codes showing on MHD.

(Temp Sensor is unrelated)

[Sgop335]

29e0 could be many reasons including fuel trims being maxed out, if adaptations fix it.
Coupled w the exhaust sounds pointing to leaks but where? pre dp or is it exhaust manifold?
Reduced power? Turbo not boosting enough? Due to manifold leak?

[JoshApple]

Originally Posted by Sgop335

29e0 could be many reasons including fuel trims being maxed out, if adaptations fix it.
Coupled w the exhaust sounds pointing to leaks but where? pre dp or is it exhaust manifold?
Reduced power? Turbo not boosting enough? Due to manifold leak?

Yes sounds like a leak somewhere but it must be pre dp. There is severe lack of power as well. No boost being built on acceleration.

Is it possible for downpipes to come loose on turbos or turbos to come loose on the block?

[Sgop335]

Dps loose on turbo is possibility and could be relatively easy check by checking the vband clamps.
But turbos loose of the manifold will cause low boost due to gases leaking and not spinning the turbo...hope not that

[JoshApple]

Originally Posted by Sgop335

Dps loose on turbo is possibility and could be relatively easy check by checking the vband clamps.
But turbos loose of the manifold will cause low boost due to gases leaking and not spinning the turbo...hope not that

I checked Vband clamps and they look intact but hard to tell without tearing the car apart.

There is also a bad exhaust smell in engine bay and into the cabin as well. Could this be indicative of option 2?

How would this even be possible LOL

[Sgop335]

Who knows,..notice how the turbos are held by the long copper nuts, and there are also gaskets for each cylinder on the exh man.
If the bad smell is recent then you know...

[JoshApple]

Originally Posted by Sgop335

Who knows,..notice how the turbos are held by the long copper nuts, and there are also gaskets for each cylinder on the exh man.
If the bad smell is recent then you know...

Yeah the smell started right when I noticed this issue. I put the turbos on myself so I am familiar with how they go on. Maybe didn’t torque a stud down enough?

Sounds like I should get ready to drop the subframe and take a closer look…

Thoughts?

[GoRomeo]

Originally Posted by JoshApple

Yeah the smell started right when I noticed this issue. I put the turbos on myself so I am familiar with how they go on. Maybe didn’t torque a stud down enough?

Sounds like I should get ready to drop the subframe and take a closer look…

Thoughts?

Thoughts? Yeah good luck ☝️☺️ Keep us posted.

[JoshApple]

Originally Posted by GoRomeo

Thoughts? Yeah good luck ☝️☺️ Keep us posted.

Meaning this is not going to easy to diagnose? Or just not fun taking the car apart😂?

[GoRomeo]

Originally Posted by JoshApple

Meaning this is not going to easy to diagnose? Or just not fun taking the car apart😂?

Yes both ☝️😂

[JoshApple]

Originally Posted by Sgop335

Who knows,..notice how the turbos are held by the long copper nuts, and there are also gaskets for each cylinder on the exh man.
If the bad smell is recent then you know...

If the smell is recent than would you guess its exhaust gasket?

Originally Posted by GoRomeo

Yes both ☝️😂

To both of you… could this be caused by anything to do with the valve cover? I would suspect not but not positive. Really trying to avoid ripping turbos out to check exhaust gaskets…

Also, probably not smart to be driving it in this condition correct? If there was bad exhaust gasket causing a leak?

[oVeRdOsE.]

does NOT mean this is your issue, but mine was the gasket at my vsrf downpipe to the oem exhaust line.

I took the time to change the rusty bolts for stainless.

Also if you want to find the leak quickly, use soapy water in a spray. It will reveal the leak.

from the video 3, there's a darker zone around the flange, and you can see fume exhaust at the top.

[JoshApple]

Originally Posted by oVeRdOsE.

does NOT mean this is your issue, but mine was the gasket at my vsrf downpipe to the oem exhaust line.

I took the time to change the rusty bolts for stainless.

Also if you want to find the leak quickly, use soapy water in a spray. It will reveal the leak.

from the video 3, there's a darker zone around the flange, and you can see fume exhaust at the top.

They might be worth changing out but I think the smoke was blow-by from the rear of the car as I had my garage door open and wind blowing in. I also put those downpipes in with the turbos and I believe they were stainless bolts.

However, upon further review… the noise definitely sounds like it’s coming from around where the turbos are at. I started it up yesterday and the noise got significantly quieter on its own somehow.

I also took off the heat shield and tightened the copper nuts for the turbos that I could reach and was surprised by how loose some of them were. Problem still persists but it’s definitely quieter. Do you think I should investigate the remaining copper nuts?

[JoshApple]

Took the car in to get a proper diagnosis

Appears to be 1) blown exhaust manifold gasket, or 2) cracked manifold

Without disassembly they could not confidently choose which one of these it is. But, it’ s definitely a leak on the manifold area. So, basically confirmed my suspicions and they quoted me 4k to replace all the gaskets.

Looks like I will be tearing the car apart myself, as previously mentioned…. yay :|

Just thought I’d update the thread for any other people with similar issues or noises. Luckily, the exhaust system is pretty straightforward and not many points of interaction so narrowing down the location of the leak is not too hard.

[oVeRdOsE.]

Originally Posted by JoshApple

Took the car in to get a proper diagnosis

Appears to be 1) blown exhaust manifold gasket, or 2) cracked manifold

Without disassembly they could not confidently choose which one of these it is. But, it’ s definitely a leak on the manifold area. So, basically confirmed my suspicions and they quoted me 4k to replace all the gaskets.

Looks like I will be tearing the car apart myself, as previously mentioned…. yay :|

Just thought I’d update the thread for any other people with similar issues or noises. Luckily, the exhaust system is pretty straightforward and not many points of interaction so narrowing down the location of the leak is not too hard.

if it's a ''or'' , means you dont know yet.

can be stupid as a o2 sensor leak.

What the shop did? visual inspection ?

before removing anything, soapy water+inspection camera of even a thermal camera.

this is not a simple job to change the manifold gasket. If it's the case, you might want to upgrade in the mean time.

It took me around 1.5h to remove 1 single turbo because I was trying not to break anything, and the engine was OUT....

[JoshApple]

Originally Posted by oVeRdOsE.

if it's a ''or'' , means you dont know yet.

can be stupid as a o2 sensor leak.

What the shop did? visual inspection ?

before removing anything, soapy water+inspection camera of even a thermal camera.

this is not a simple job to change the manifold gasket. If it's the case, you might want to upgrade in the mean time.

It took me around 1.5h to remove 1 single turbo because I was trying not to break anything, and the engine was OUT....

They confirmed the leak is coming from the exhaust manifold area. They did a smoke test and listened with stethoscope but were unable to determine whether it was a gasket or a crack in the manifold. This is because they did not have good enough vision. Attached is the technician notes.

I am confident it’s not an 02 sensor. I replaced the turbos on jackstands with the engine still in the car so I’m fairly capable of removing the turbos to inspect the gaskets. It’s just a heavy time investment.

You’re not wrong that it would be a good time to upgrade…. But I cannot afford it at the moment.

[oVeRdOsE.]

oh you've already changed the turbo. Makes sense for the gasket.

Those are brittle, and can be easily cross pushed.

If you're rwd, then bit easier for sure.

You can always do a rebuilt too, with upgraded parts. bimmer barn did a great how to on youtube

[JoshApple]

Originally Posted by oVeRdOsE.

oh you've already changed the turbo. Makes sense for the gasket.

Those are brittle, and can be easily cross pushed.

If you're rwd, then bit easier for sure.

You can always do a rebuilt too, with upgraded parts. bimmer barn did a great how to on youtube

Yes rwd here. They are slightly upgraded already. They are the Vargas ones with the upgraded billet wheel and waste gate assembly.

[JoshApple]

Well I have found the cause of my mysterious exhaust leak, if anybody was curious.

See attached photos of the wastegate flapper, oh wait, there isn’t one!!!!

I would have to conclude that this would be the cause of my issues, exhaust gaskets are intact!

Does anybody know if Vargas turbos would be willing to help me out here? I know there are some Vargas personnel on this forum, maybe somebody can tag them?

It’s kind of ridiculous that the wastegate failed this horribly and got sucked down into my exhaust clearly as the whole flapper assembly is gone. Turbos have maybe 40k-ish miles on them.

Thanks