[Haus_07]

So, like many of you, my wastegates also rattle like hell, and this is the conclusion to all of my research and attempts to identify, then finally fix the problem. I won't go into to much detail about me, but know that I'm a true gearhead, been working on all kinds of cars for 25+ years, and I easily understand the way mechanical things work. First off, you need to really know what's going on inside the wastegates while they are operating, and what parts are responsible for what. Once you understand what's going on, it's much easier to come up with a fix, and the one I've come up with is very simple, yet effective. Here's a pic of the inside of the wastegates that come with the Mitsubishi T03/04 turbos on our cars:



Uploaded with ImageShack.us

See the little disk looking thing? That's the part the is attached to the arm that comes out of the wastegate, which is supported by a bushing, and is attached to the arm of the wastegate actuator. This picture is of when the wastegate is open, (no boost. exhaust gasses pass through the hole and into the downpipes) and it seats on the machined area just behind it when it's closed. (full boost. all exhaust gas is diverted into the hot side of the compressor, then out into the downpipes)

Now, there are many kinds of rattles. Some experience rattle when @WOT, and others, like myself, have it at idle, or just off idle, and some rattle on deceleration. There are 3 possible areas that could be causing the noise, but I believe that really there is only one major culprit.

At first I thought it was area number 1 that was causing all the noise, and that's where the actuating rod connects to the wastegate arm via a small c-clip. There was a lot of slop in that connection, so I put a washer in between the actuating rod end and the attach point on the wastegate arm. This did little to nothing to quiet it down. So then, I thought I had it figured out with location 2, which is where the wastegate arm is held by a bushing that's pressed into the wastegate body. There was a lot of extra movement in this area, and after reading a post by Rob Beck, it definitely is an area that wears out fast, and is a poor design finished off with poor materials. I put a c-clip in between the bushing and the wastegate rod, which took up all the side to side movement. I thought for sure I had it this time, but all it did was bind up the action of the wastegate, and it still rattled.

So, the third location, which I believe to be the primary culprit, is that little disk that's attached to the wastegate arm, and is responsible for directing exhaust flow. That disk is designed to float, and according to bmw, it has to in order to make a proper seal when the wastegate is fully closed. Well, when I was changing out my DP's, I had a chance to take a look at mine, and it does a lot more than float. It's loose as all hell, and spins around in there very easily, and there is a ton of slop every which way you can move the thing.

This is what I believe is happening, and after reading a recent post by Rob Beck, he also believes the same thing. The closer that disk is to the exhaust flowing through that hole, the more it's going to rattle at idle. If it doesn't close all the way against that seat, it's also going to rattle. That's why some have rattle at idle (adjusted to short) and others have rattle at WOT (adjusted to long, and not closing all the way). Here's what I did for a little test of my conclusion. I adjusted the actuator rod so that it was quite a bit longer than stock, thus moving the disk away from the flowing exhaust. With the car running, I then hooked up a vacuum pump to the actuator, and slowly began to draw it closed. The closer it got to the exhaust flow, the more it was rattling, and it was the same exact rattle that I'd been hearing for I don't know how long!!!

The fix: If your wastegate rattles @idle, untighten the lock nut on the actuator shaft (10MM open end wrench) and lengthen the arm one full turn by turning it clockwise. (if your looking at it from the front of the car) Start the car, and listen for the rattle, If it's still there, give it another turn, and start the engine again. I adjusted mine 1 full turn, and all of my rattle at idle is gone because the disk was moved just far enough away from the exhaust gas that it's not rattling anymore (or at least not enough that I can hear over the engine running) Reverse the process and turn the rod clockwise to tighten one turn if your getting rattle under full boost, as the disk is to far out, and is not seating against it's seat.

A few notes and cautions on this fix. There could be other reasons why your disk isn't closing all the way, like a weak actuator, so you need to make sure all of your other components are working properly, and you don't have any vacuum leaks before you make these adjustments. Also, if you lengthen to much, the disk will not seat either, because the actuator has a limited throw, and only moves so far, hence why I say one turn at a time. If your showing more than 30 threads on the actuator rod, I believe you've gone to far.

One more thought: I believe the reason that so much lag was induced when BMW updated with the 29.2 software, is because they know this is the problem, and they are fixing it the exact same way I just showed you, but they are doing it with the software that controls the actuators. The lag is so bad because they programmed the DME to push the actuator rod out farther to eliminate the rattle, but the farther away it is, the more time it takes to get all the way closed, thus inducing lag. I induced a little lag by lengthening mine, but counteracted that by turning up the lag fix in my jb4 from 80 to 85
Now, I have no more rattle, no more lag, and I'm pretty sure that when I hit my 16.5lb boost target running race gas on my custom map 6, that it's closing all the way.

I hope that this helps educate those who don't understand what's going inside their wastegates, and sheds a little light on how to fix the problem without throwing money at it, or spending countless hours arguing with the dealership!! If I've missed something, or you don't agree with my conclusions, then by all means please chime in, but I'd really appreciate it if your criticism stay constructive. Oh, and by all means, this is at your own risk, and I take no responsibility what so ever if you F up your car!!!

[Jeff@TopGearSolutions]

Great post. This should help many people.

[Haus_07]

Originally Posted by Jeff@topgearsolutions

Great post. This should help many people.

Thanks man!! I spent a lot of time in front of the computer reading and researching, and many hours in the garage cursing when most of my fixes failed. Hopefully some guys (and girls) can learn from my mistakes and have a better understanding of what's going on under their hoods!!!

[enrita]

[Big Tom]

Originally Posted by Haus_07

The fix: If your wastegate rattles @idle, untighten the lock nut on the actuator shaft (10MM open end wrench) and lengthen the arm one full turn by turning it clockwise. (if your looking at it from the front of the car) Start the car, and listen for the rattle, If it's still there, give it another turn, and start the engine again. I adjusted mine 1 full turn, and all of my rattle at idle is gone because the disk was moved just far enough away from the exhaust gas that it's not rattling anymore (or at least not enough that I can hear over the engine running) Reverse the process and turn the rod clockwise to tighten one turn if your getting rattle under full boost, as the disk is to far out, and is not seating against it's seat.

I've tried adjusting the WG arm, without any results at all.
My wastegates are rattling on falling rpm's pretty noticeably.

And what about the front turbo, which is impossible to reach?
I guess you're doomed if that one is starting to rattle...

The ONLY thing that really worked for me is the PROcede WG Rattle Fix.
...and the Rattle Fix is now even possible to have enabled 100% of the time, even if the oil temp is low.

I love being 100% rattle free at all time, and the car feels like a premium car again!

[franzzz]

Great Job Haus_07

In my car rattle are present only in cold situation
(startup)

[Haus_07]

Originally Posted by Big Tom

I've tried adjusting the WG arm, without any results at all.
My wastegates are rattling on falling rpm's pretty noticeably.

And what about the front turbo, which is impossible to reach?
I guess you're doomed if that one is starting to rattle...

The ONLY thing that really worked for me is the PROcede WG Rattle Fix.
...and the Rattle Fix is now even possible to have enabled 100% of the time, even if the oil temp is low.

I love being 100% rattle free at all time, and the car feels like a premium car again!

Yeah, I too have a little rattle on decel also. Not sure there's much I can do about that, mechanically that is. I think for some of us who are modded pretty heavily, there's only so much adjustment in the actuator rods, and if your disk is to loose, there won't be a way to adjust the rattle out of it. I've heard good things about procede's fix for the rattle, and ultimately a software fix in my opinion is the way to go!! I hope that Terry can follow suite and add something similar for us jb4 users!!

As far as the front turbo, I did an experiment with mine, and with the downpipes off, it is possible to adjust that wastegate. I tightened mine by one turn for a little extra boost, but it's not an easy job at all!!

[BMWsky]

Awesome post, thank you.

[Rob@RBTurbo]

I believe you'll need to be careful to get both actuators adjusted such that they both close the wastegates to the same "tension" at the same amount of applied vacuum. Also once these start "really" wearing, the shafts will wear oblong and their open/close operation will suffer severely to the point of binding. Additionally the radial play developed in the shaft/bushing will also cause the flapper to not fully seat.

I do believe your issue will come back. If BMW couldve saved hundreds of thousands of dollars by adjusting the wastegate further outward, they would have (they did make many different attempts, some helped some didnt). The real issue is that at a certain point the internal wastegates need to be trashed and replaced with new components (or replaced turbos).

[vasillalov]

Haus_07,

Great post! Very informative!

I have a couple of questions related to this wastegate rattling deal:

1. Is this mileage related? I have 25K on my 2008 N54 and I have never heard any rattling at all. I had to watch youtube videos to understand what people are experiencing.

2. Is this rattling issue related to a specific batch of turbos or are all of them affected? As a side question to this: any rattling issues with N55 engines?

[Xander]

The dealer had my car all last month to try and figure this out. They gave up and gave me new turbos. I <3 CPO.

X...

[Haus_07]

Originally Posted by RobBeck

I believe you'll need to be careful to get both actuators adjusted such that they both close the wastegates to the same "tension" at the same amount of applied vacuum. Also once these start "really" wearing, the shafts will wear oblong and their open/close operation will suffer severely to the point of binding. Additionally the radial play developed in the shaft/bushing will also cause the flapper to not fully seat.

I do believe your issue will come back. If BMW couldve saved hundreds of thousands of dollars by adjusting the wastegate further outward, they would have (they did make many different attempts, some helped some didnt). The real issue is that at a certain point the internal wastegates need to be trashed and replaced with new components (or replaced turbos).

I completely agree. From what I've read, and most of the good information I got on this subject came from you, Mr. Beck, the materials used in these wastegates are sub-par, and they will eventually wear out. I created this post so that people have the insight and know how on how to keep their wastegates as close to rattle free as possible, for as long as possible. It's really aimed at those of us who are no longer covered by any warranty, and don't have the funds to rebuild the wastegates properly. My issue will come back as that bushing wears more, just like you stated. I'm basically trying to get as much life out of the stock wastegates for as long as I can, but eventually, they will have to be replaced. When that time comes, I will be coming to you, because I think that you have the best permanent solution out there. Rebuild them with the proper materials. Thanks for all your work on this subject, by the way!!!

[ModBargains III]

Great post. Thanks for the info, this should help out a ton of forum members

[Haus_07]

Originally Posted by vasillalov

Haus_07,

Great post! Very informative!

I have a couple of questions related to this wastegate rattling deal:

1. Is this mileage related? I have 25K on my 2008 N54 and I have never heard any rattling at all. I had to watch youtube videos to understand what people are experiencing.

2. Is this rattling issue related to a specific batch of turbos or are all of them affected? As a side question to this: any rattling issues with N55 engines?

It would make sense that the more miles put on the car would warrant worn wastegate parts (rattle), but it seems to be hit and miss with these cars. I've read most of the rattle related posts on this site, and some guys have none with over 60k, and some deal with it right outta the box. I would say it's not that great of a design to begin with, and the materials used in the wastegate components definitely weren't made to last a life time. How much boost your running and how aggressive you are with your car also come into play.

As far as the N55 is concerned, I don't know what they are using for a wastegate, so I can't comment on that. As far as I know, there are upgrades turbos by BMW that are replacing the first generation, but again not sure if any changes were made to the internals. Maybe someone with more knowledge in this area can enlighten us?? (cough....cough...rob???)

[therealm3]

Originally Posted by Haus_07

It would make sense that the more miles put on the car would warrant worn wastegate parts (rattle), but it seems to be hit and miss with these cars. I've read most of the rattle related posts on this site, and some guys have none with over 60k, and some deal with it right outta the box. I would say it's not that great of a design to begin with, and the materials used in the wastegate components definitely weren't made to last a life time. How much boost your running and how aggressive you are with your car also come into play.

As far as the N55 is concerned, I don't know what they are using for a wastegate, so I can't comment on that. As far as I know, there are upgrades turbos by BMW that are replacing the first generation, but again not sure if any changes were made to the internals. Maybe someone with more knowledge in this area can enlighten us?? (cough....cough...rob???)

I would love to hear some insight on the newer turbos as well. I had ridiculously bad rattle (idle, acceleration, and deceleration) and my dealer got BMW to pony up for complete turbo replacement. they also ended up replacing the vacuum pump as it was found to be producing too little vacuum to close the wastegates properly after they put the new turbos in. the turbos they put in have a newer part number but I have no clue as to what the changes are. It would be nice to know if these are going to last longer than 35k miles like the first ones. BTW, no tune on my car. completely stock motor.

[///M3THOD]

I just put brand new turbos on my car.. out of pocket. I still have wastegate rattle present on crank and sometimes on decel while the clutch is still engaged.

Haus is correct. The majority of the rattle is from the wastegate disk, which is about the size of a quarter, rattling around as exhaust gases pass it, as well as when it makes a seal on the seat for some folks.

Its really just a poor design. I'm surprised that the proto N54's running these Mistu turbos didn't log this in their reliability testing. Its such a common problem among N54 equipped vehicles that it must have been present in some test vehicles.

[therealm3]

Originally Posted by ///M3THOD

I just put brand new turbos on my car.. out of pocket. I still have wastegate rattle present on crank and sometimes on decel while the clutch is still engaged.

Haus is correct. The majority of the rattle is from the wastegate disk, which is about the size of a quarter, rattling around as exhaust gases pass it, as well as when it makes a seal on the seat for some folks.

Its really just a poor design. I'm surprised that the proto N54's running these Mistu turbos didn't log this in their reliability testing. Its such a common problem among N54 equipped vehicles that it must have been present in some test vehicles.

you might want to have them check your vacuum pump. I got my turbos replaced and it rattled with the new ones. After pump replacement the noise was gone and hasn't come back. Worth a shot, you know?

[Joshboody]

Just a note that the flapper is only really seated during idle and cruise I would think. Under boost it will be mostly passing gas (hehe) and this will be constant per your boost target/rpm no matter the wastegate mechanical adjustment.

I do think it's 2 parts: flapper and linkage, but majority from the flapper probably. My hesitation to adjustment is that I don't want to incidentally give 1 turbo more work and thus varying exhaust manifold pressures. Plus my brain can't comprehend reaching the front wastegate.

[///M3THOD]

Originally Posted by therealm3

you might want to have them check your vacuum pump. I got my turbos replaced and it rattled with the new ones. After pump replacement the noise was gone and hasn't come back. Worth a shot, you know?

Yeah, definitely.. thanks. How badly did yours rattle?

[Haus_07]

Originally Posted by therealm3

you might want to have them check your vacuum pump. I got my turbos replaced and it rattled with the new ones. After pump replacement the noise was gone and hasn't come back. Worth a shot, you know?

This is a really good idea. I wonder how much vaccum the pump is supposed to create? If we knew the spec, it would be really easy to hook up a vaccum guage and find out wether or not the pump is working properly. Does anyone know what the BMW spec is for vaccum? This would be a great place to start, by eliminating as many variables as possible, and this would be a major one!! HELP GUYS!!! I think with all the combined knowledge on this board, we should be able to figure out chinese math if we needed too!! (sorry, just a saying. No racism intended. )

[prelude2perfect]

How much does a new vacuum pump cost though?

[bimmertt]

Isn't this the Mr. 5 fix except you are saying to loosen the rod instead of tighten it?