Z4 Rear Solenoid Plumbing

BQTuning

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Jul 18, 2017
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E89 Z4 35i 6MT M Sport
Not sure if this is a diagram error but I found the rear turbo solenoid plumbing on the Z4 E89 with the Z4 is setup differently from all ther other N54 cars ?

This diag presents all cars with the N54 except the Z4

1273x768.png.79fdba61ec3f4d0ca29f650a5987fe41.jpg


This diagram is the E89 Z4 with the N54

1299x884.png.d3232b1c42ec44e9abbcc95de1679bef.jpg
 

NoQuarter

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Z4 35is, 535xi, X5 35i
Got a cliff's notes of the difference? hard to scroll up and down and look for the difference.

I removed the vacuum canisters a while back. Haven't noticed any reason to put them back but still thinking about putting one of them back to share between both turbo's. Maybe a single solenoid as well? if the the solenoid from the 7 series is bigger then maybe just one of those??
 

BQTuning

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Jul 18, 2017
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E89 Z4 35i 6MT M Sport
Got a cliff's notes of the difference? hard to scroll up and down and look for the difference.

I removed the vacuum canisters a while back. Haven't noticed any reason to put them back but still thinking about putting one of them back to share between both turbo's. Maybe a single solenoid as well? if the the solenoid from the 7 series is bigger then maybe just one of those??

yea, on the solenoid for the rear turbo the vacuum canister connects to the outer part of solenoid, and the gate hose connects to the inner part of the solenoid

on the E89 its in the reverse; the gate hose is connected to outer part of the solenoid and the canister connects to the inner part of the solenoid.
 

BQTuning

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Jul 18, 2017
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E89 Z4 35i 6MT M Sport
Got a cliff's notes of the difference? hard to scroll up and down and look for the difference.

I removed the vacuum canisters a while back. Haven't noticed any reason to put them back but still thinking about putting one of them back to share between both turbo's. Maybe a single solenoid as well? if the the solenoid from the 7 series is bigger then maybe just one of those??

Forgot to reply to the rest of you question. I am thinking since the DME has two boost solenoid output signals it modulates between them both for each IWG on each bank. It cant do this using only one solenoid for both wastgates IMO. Although it still works as it is done on ST setups I feel we are taking something elaborate away from the DME.
 

fmorelli

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E89 Z4 35i, F10 535d
It's actually confusing as hell:
  • The N54T diagram vacuum tank drawing orientations confuse the situation, along with the fact that the Z4 uses more current software for their designs, which shows a literally different visualization (i.e. coloring).
  • The E89 drawing connects the vacuum tank and solenoids in matching location pairs, whereas the N54T diagram shows the back vacuum tank mounting to the front drawn solenoid. I only point out this fact as it could cross up representation.
  • The Z4 uses two different p/n vacuum canisters. The N54T uses two of the same canisters (which happen to match one of the two part numbers used in the Z4). This is probably a packaging/mounting difference, not a functional difference.
  • To your point on the solenoid connections ... the N54T diagram only shows a vacuum canister connection. They don't show the connection to the turbo side (to the little elbow), whereas the Z4 drawing shows both the canister and "elbow" connection.
My vote is the drawing could well be wrong. It wouldn't be the first time. I just had to rebuild the fuel rail on an M44 ... diagrams for fuel delivery are so wrong its not even funny (hard line versus soft line, o-rings missing,etc). But I'm pretty sure those solenoids have a vacuum side (they are not interchangeable connections). One other side-note: pretty cool how two solenoid from wastegate vacuum and they both "T" into a shared line. Not sure what the dirty details are there, but correct me if I'm wrong: one could continue to get vacuum to both wastegates if one solenoid shit the bed?

Filippo
 
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BQTuning

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Jul 18, 2017
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E89 Z4 35i 6MT M Sport
It must be an error, cause as I recalled the hook up was the same as the front boost solenoid when I was going though my conversion