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N52 intake to throttle body - what are these parts?

441 Views 3 Replies 2 Participants Last post by  jonwilli
I was going through some of the bits and pieces in my garage and came across this part (BMW part number 7559121), it is the plastic pipe that connects the MAF/air box on the N52 engine to the throttle body on the plenum. There are two bits on this that I wasn't sure what their function was and wondered if anyone knew? They are both bits you never notice when the part is fitted in the engine bay as I think they sit underneath the pipe. They are the angular plastic box and the smaller bent pipe, see photos below.

Both pieces have open tubes off the main intake pipe. The angular box is sealed (is it some sort of simple resonator?). The pipe with the 180 bend on it has a foam filter on the end of it (see last photo) so ay first thought it might have something to do with the EVAP system, however, I took it apart and it appears sealed by some plastic bellows. I wondered if this was to absorb small shock waves when the throttle is suddenly closed at wide open throttle...just an idea!

Another unrelated question does anyone know where the EVAP valve is located on the N52? I can find the OEM diagram, it is part numbers 7530976 and 7618643, but I can not find where it locates in the engine bay. I think on older BMWs it used to be near the alternator...

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Helmholtz resonators are usually employed to cancel out an unwanted frequency (drone).
marco_polo said:
Helmholtz resonators are usually employed to cancel out an unwanted frequency (drone).
Thanks Marco, I had pretty much come to that conclusion myself just wanted to confirm. I guess the old rubber intake pipes with the reinforced latticing (a la E36) probably weren't as affected as the intake pipes were heavier and more rigid?
Also any idea where the EVAP valve is on the N52?
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