Has anyone noticed there are 2 different throttle bodies for the N54?

proboner

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Sep 13, 2020
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So while doing some regular maintenance which requires me to remove the intake manifold/throttle body, I decided to be extra responsible and replace the throttle body gasket. I went to throw on the new one and immediately realized it was NOT going to work. It just so happens I have two other throttle bodies in my possession, so I took them out to compare and found something unexpected (to me at least):
  • Stock (Continental) throttle body
    • Groove depth for throttle body gasket/oring- 5mm
    • Stock gasket/oring (black color) height- 6.5mm
    • Elring (OE) gasket/oring (black color) height- 7mm
  • OE (Siemens/VDO) throttle body
    • Groove depth for throttle body gasket/oring- 8mm
    • Corresponding (unsure of brand, came with the TB) gasket/oring (green color) height- 11mm
So basically I tried to install an Elring 7mm tall gasket into the grove of the Siemens/VDO throttle body which is 8mm deep. Obviously this will not work, as the gasket/oring sits 1mm below the height of the mating surface.

Just found this super weird and a potential issue for people if they didn't realize what was going on and fit the wrong gaskets to the wrong throttle body.
 

Friguy

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Aug 9, 2022
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I'm surprised no one has gotten on this info yet. But I have been losing my mind trying to stop a back pressure issue for over a year and I've bought two throttle bodies with O Rings from BMW to ensure I'm getting the correct ones and still I have thing "Wheezing" sound when I'm not on throttle and on cold start or almost any start actually. I've also had three different charge pipes on it. I'm running an ARM Motorsport one at the moment. I know it's coming from the charge pipe to throttle body letting air escape! I can hear and feel it come out. I've never heard of this being something before unless there are Z4 ones that might be different or something. I don't know. If I could get any more info on this or advice or where to find the throttle bodies you got hold of?? Thanks for your time etc.
 
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proboner

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Sep 13, 2020
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I'm positive of this. I've got them sitting in my garage now and took a video, which I can upload if it will be helpful. It's pretty easy to diagnose... just remove your throttle body and look at how the o-ring fits. I can imagine 2 potential issues:
  1. Smaller o-ring in larger throttle body groove- causes the o-ring to sit fully within the groove of the TB and provides no seal at all
  2. Larger o-ring in smaller throttle body groove- could cause the o-ring to be too tall and not seat correctly, resulting in a leak
I'd check for both. Do you have a dial caliper?
 

Friguy

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Aug 9, 2022
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Calgary, AB, Canada
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2008 335XI N54, 2005 E46 M3
I'm positive of this. I've got them sitting in my garage now and took a video, which I can upload if it will be helpful. It's pretty easy to diagnose... just remove your throttle body and look at how the o-ring fits. I can imagine 2 potential issues:
  1. Smaller o-ring in larger throttle body groove- causes the o-ring to sit fully within the groove of the TB and provides no seal at all
  2. Larger o-ring in smaller throttle body groove- could cause the o-ring to be too tall and not seat correctly, resulting in a leak
I'd check for both. Do you have a dial caliper?
Sorry for my slow reply. No I don't have a dial caliper however I need to check on the two TB's I have and see if they are both Continental or Siemens or one of each or even some other brand. I have been going nuts trying to figure out why I can't solve the back pressure problem. Meaning when I'm on boost the car has no leak the millisecond it is not on boost like a gear change or anything Wheezing or a sucking sound. I can feel the air coming out of the charge pipe to TB connection and I've bought three different O rings with no change. I'll comment back once I look into the brands hopefully tomorrow. A fix for this would be like a miracle to me! LOL. Oh and the video would be very helpful if you could share it please. From the way you are describing this I think you are comparing the Charge pipe O ring grooves and not the TB to manifold. But maybe I'm misunderstanding you. Thank you again!
 

SlowE93

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So while doing some regular maintenance which requires me to remove the intake manifold/throttle body, I decided to be extra responsible and replace the throttle body gasket. I went to throw on the new one and immediately realized it was NOT going to work. It just so happens I have two other throttle bodies in my possession, so I took them out to compare and found something unexpected (to me at least):
  • Stock (Continental) throttle body
    • Groove depth for throttle body gasket/oring- 5mm
    • Stock gasket/oring (black color) height- 6.5mm
    • Elring (OE) gasket/oring (black color) height- 7mm
  • OE (Siemens/VDO) throttle body
    • Groove depth for throttle body gasket/oring- 8mm
    • Corresponding (unsure of brand, came with the TB) gasket/oring (green color) height- 11mm
So basically I tried to install an Elring 7mm tall gasket into the grove of the Siemens/VDO throttle body which is 8mm deep. Obviously this will not work, as the gasket/oring sits 1mm below the height of the mating surface.

Just found this super weird and a potential issue for people if they didn't realize what was going on and fit the wrong gaskets to the wrong throttle body.
Aren't "stock" and "OE" the same thing ?
OEM would be different from these 2 as I understand it.
 

ShocknAwe

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There's genuine, this is the actual part with the bmw stamp on it.

OE is manufactured by the same company contracted by bmw so same part without the stamp on it. Can be really hard to figure out who the original manufacturer or supplier is, or if it has changed over time and who the CURRENT supplier is with the most fixed/updated part.

OEM is the same part number but made by another commonly used brand, just not the same as the genuine/OE. There may be small variations from the OE/a genuine part in this scenario. Usually fine though.


So, if there are two throttle bodies that means there are two part numbers that are physically different. The above characterisations then apply to each part independently.

Clear as mud right?
 

SlowE93

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There's genuine, this is the actual part with the bmw stamp on it.

OE is manufactured by the same company contracted by bmw so same part without the stamp on it. Can be really hard to figure out who the original manufacturer or supplier is, or if it has changed over time and who the CURRENT supplier is with the most fixed/updated part.

OEM is the same part number but made by another commonly used brand, just not the same as the genuine/OE. There may be small variations from the OE/a genuine part in this scenario. Usually fine though.


So, if there are two throttle bodies that means there are two part numbers that are physically different. The above characterisations then apply to each part independently.

Clear as mud right?

OE And stock is same according to them.
OE is same as Genuine (stock) from when car left factory
 

proboner

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Sep 13, 2020
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My terminology in the original post may be off. As well, I'm just assuming whatever TB came on my car is stock, while it may have been replaced and thus, not original. All I know is it's very clear there are at least 2 different TBs when it comes to this groove for the oring/gasket to sit in, as well as the size of the oring/gasket
 
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SlowE93

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Screenshot_20230709_123722_Samsung Internet.jpg

Read closer.

I don't disagree that OE and genuine are the same part, but it doesn't have the stamp, so they aren't "the same"
Ok if you say so....please explain why OP has different measurements if you do NOT disagree it is the same part minus the stamp.
 

SlowE93

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My terminology in the original post may be off. As well, I'm just assuming whatever TB came on my car is stock, while it may have been replaced and thus, not original. All I know is it's very clear there are at least 2 different TBs when it comes to this groove for the oring/gasket to sit in, as well as the size of the oring/gasket
All good, and thanks for posting that as it may very well help other people in the future.
 

proboner

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Since this is becoming a bit more hotly debated, I'm posting some pictures to show what I'm talking about. Need to edit the video and then I'll post that as well.

"Stock" (Continental brand- whatever it is, it was originally installed on my car) throttle body. Notice that the black gasket protrudes a couple mm above the mating surface:
LQADVsp.jpg


"Non-stock" (Siemens/VDO brand- whatever it is it did not come on my car) throttle body. Notice the green gasket also protrudes a couple mm above the mating surface:
zjOF8AW.jpg


"Stock" throttle body with green "non-stock" gasket. Notice it sticks WAY above the mating surface:
KKFlpIe.jpg


"Non-stock" throttle body with black "stock" gasket. Notice it sits below the mating surface:
KPCZX8K.jpg
 

SlowE93

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Since this is becoming a bit more hotly debated, I'm posting some pictures to show what I'm talking about. Need to edit the video and then I'll post that as well.

"Stock" (Continental brand- whatever it is, it was originally installed on my car) throttle body. Notice that the black gasket protrudes a couple mm above the mating surface:
View attachment 83103

"Non-stock" (Siemens/VDO brand- whatever it is it did not come on my car) throttle body. Notice the green gasket also protrudes a couple mm above the mating surface:
View attachment 83104

"Stock" throttle body with green "non-stock" gasket. Notice it sticks WAY above the mating surface:
View attachment 83105

"Non-stock" throttle body with black "stock" gasket. Notice it sits below the mating surface:
View attachment 83106
Huge difference !
 

rayrobot

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Jul 31, 2019
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Where can we find the black gasket? I had the same issue and i've used and crushed the green gasket on the continental throttle body. Basically hopefully making it work. I knew something was off.

FCPEuro only shows the green gasket.

1689001409811.png
 

proboner

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Sep 13, 2020
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That's funny, FCP only shows the black gasket for me... Try looking it up under a 2011 z4 35i and see if that changes your results
 
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rayrobot

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That's funny, FCP only shows the black gasket for me... Try looking it up under a 2011 z4 35i and see if that changes your results
Hmm, I searched up by part number.

13547522361 - same results. Did yours have a different part number?

 

Friguy

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Aug 9, 2022
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Different part number...

View attachment 83150
Okay so as I was concerned about in the earlier text the "O ring" you are talking about isn't the "O ring" I'm talking about. I was talking about the O ring that is between the charge pipe and the TB. Not the one between the TB and the Manifold. But thank you for the information. Oh as well i was looking though the many TB's on Ebay and Amazon and what I found is that the Continental brand of TB's seem to only be for the N55 engine. I'm not sure of the differences between the two really or if they are interchangeable but I looked through hours of them looking for the Siemens and Continental brands on them and the only ones that I could find on there from Continental were the N55 engine and not the N54. Anyway I'm still wallowing in my very frustrating problem of the back pressure from the boost (when it's off throttle even in very small increments) leaking out and causing the car to make high pressure air escaping sounds and it's frustrating. Please read my original post after the actual OP put his findings up. (Mine are the Second one and fourth I believe). If ANYONE has had this problem please let me know how you fixed it. As my Post says I've tried a lot of money draining things to remedy it and Nothing will seal it up permanently. Thank you again Proboner.
 
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Friguy

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Aug 9, 2022
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Calgary, AB, Canada
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2008 335XI N54, 2005 E46 M3
WAIT just one SKOOCH!! I've been feeling the air pressure coming out of the TB and it's been hard to tell exactly where it's coming out. Perhaps it's coming out of there and NOT at the Charge pipe??! Hey I'm goiing to try to get another one of these as the one I put in is the green one and perhaps I need the Black one (Different part numbers). I'll look on "realoem" and see what mine is supposed to use or if I have the wrong one. THANK YOU. Here's hoping!
 
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