[MiniMeRage]

Hey everyone,
Im new to this forum, had to join because I am stumped.
I've got an 07 335i that I just put new CHRA's and relocated inlets. Car was running great until I heard a pop followed by a whining noise.

After checking MHD, it shows that im not making any boost. So I checked all my piping and charge pipe, no leaks. I took the connection to the charge pipe off and had a friend bring up the revs, and I can feel that its pushing quite a bit of air. So it seems like it is making boost, but not reading.

I did figure out that if I pop the vacuum line off either boost solenoid the whining goes away. So I foolishly bought two new solenoids from BMW and installed them. Still makes the noise. So I figure it has something to do with vacuum, but cant quite find the culprit.

I dont have a video of my car, but I found a previous unresolved thread where they had a video of the same noise. If anyone has any ideas I'd appreciate it!

[335boston]

I have herd the turbo being blown causing this whine noise before , but I’ve I also know from experience the car will not build any boost at all if you have a massive boost leak. I had a “pop” noise and no boost and found it to be a blown silicone coupling , any shops around you to do a smoke test ?

[MiniMeRage]

Originally Posted by 335boston

I have herd the turbo being blown causing this whine noise before , but I’ve I also know from experience the car will not build any boost at all if you have a massive boost leak. I had a “pop” noise and no boost and found it to be a blown silicone coupling , any shops around you to do a smoke test ?

I've got a local shop that has done smoke tests for me before. I'll see if i can get it in sometime this weekend.

Im still curious why the noise would go away when I unplug the boost solenoids. Could the Vacuum Canisters be bad? I know they are essentially empty cylinders, but if one had a crack could it cause the noise?

[335boston]

Originally Posted by MiniMeRage

I've got a local shop that has done smoke tests for me before. I'll see if i can get it in sometime this weekend.

Im still curious why the noise would go away when I unplug the boost solenoids. Could the Vacuum Canisters be bad? I know they are essentially empty cylinders, but if one had a crack could it cause the noise?

I could see them being cracked and making the noise , I think bms actually sells billet ones now . While you have them smoke testing your intake ask them if they’ll do the vac lines too shouldn’t be super hard if they got the right fittings.

Could also buy a smoke test machine on Amazon , uses baby oil to produce the smoke, it’s probably the best 200$ I invested in “tools” I’ve found countless boost leaks/ issues with it .

[MiniMeRage]

Originally Posted by 335boston

I could see them being cracked and making the noise , I think bms actually sells billet ones now . While you have them smoke testing your intake ask them if they’ll do the vac lines too shouldn’t be super hard if they got the right fittings.

Could also buy a smoke test machine on Amazon , uses baby oil to produce the smoke, it’s probably the best 200$ I invested in “tools” I’ve found countless boost leaks/ issues with it .

Over the weekend I'll try to get it smoke tested and have the vacuum lines checked. I just replaced all of them with silicone, but wouldn't hurt to double check.

I really should look into getting a smoke tester, would be very useful with tuned FI cars.

[Mustafa.e92]

the turbos are setup to make boost only with vacuum applied so if a malfunction happens like let’s say a burned vacuum line to the actuator your stuck with no boost. The wastegates are naturally in the open position until vacuum is applied to shut them and create boost. When you disconnect the boost solenoid so no boost is created.
Sounds like theirs a boost leak. Go over all your connections.
Throttle body o ring
Charge pipe couplers
Intercooler connections
Turbo outlets
You can order a smoke tester online for cheap comes in handy a lot.

[Mustafa.e92]

I just watched that video. It doesn’t sound like a boost leak more like turbo failure. Blades hitting the housing when making boost. Disconnecting boost solenoid just makes the turbo not spool so no noise.
Pop off the inlets or downpipes and take a peak at the turbos

[MiniMeRage]

Originally Posted by Mustafa.e92

I just watched that video. It doesn’t sound like a boost leak more like turbo failure. Blades hitting the housing when making boost. Disconnecting boost solenoid just makes the turbo not spool so no noise.
Pop off the inlets or downpipes and take a peak at the turbos

I did check over the vacuum lines and there weren't any leaks, I suspect you are right about the turbos.
Unfortunately they are brand new (<500miles) CHRA's from VTT. Really disappointed they only lasted this long.

[335boston]

How much boost were you running with them?