s54 AA Prima+ kit not making over 8psi. plz help

[l0lwut123]

Hi there,

Ive tried some googling for this before posting but nobody seems to have a build thread with pictures, or if there are links to a thread, the site the thread was on is down. Also searched prima in the bimmerforum search with no luck


Ive got a 2003.5 that i recently put a prima plus supercharger and methanol injection kit on.

Took the car out to a dyno day, and im only making about 390 wheel, when i should be above 500. Teed into the line going to the hobbs to control the methanol, and according to the boost reader on the dyno station, the car is not making over 8psi, however it is supposed to be making closer to 15.

Things I've verified:

• the methanol tank is full
• the vacuum lines are plumbed correctly to the best of my knowledge
  
  • there is no actual vacuum diagram provided by the vendor/manufacturer, only instructions telling where to run which hoses for what from the vacuum rail.
  • emailing with the vendor so far to the best of my knowledge the hoses are plumbed correctly.

Things i have noticed:

• both BoV's vent to atmosphere at idle
• the rear one with considerably more pressure than the front
• if i flip the toggle on the hobbs to off, the front BoV stops venting, but the rear starts venting a bit higher pressure
• in the instructions the kit says the side solenoid should have the rear port open, but the pictures show it covered.

Relevant pictures:
https://imgur.com/a/OoYhl3x

Is anyone here running this kit and can you provide a vaccuum diagram/pictures of how you ran it?
does your kit vent to atmosphere at idle?

thanks in advance

[lisnowboarder]

Curious to see how this gets solved. Google and bimmerforums is full of yes/no bov open at idle comments.

A few comments I think may help someone smarter than me.
Is the kit new?
Can you verify the pulley is the correct size for the psi?
I assume when you flip the switch one bov (rear) opens enough to release enough air that the other does not need to open. However this could only occur if there was a vast difference in vac line length/type or leak between the two that would allow a pressure differential. But this wouldn’t cause you to leak several psi but could be an issue later.
Lastly I happen to have an AA bov like yours and noticed an adjustment on the top to tighten the diaphragm. I have yet to install but if this was weak on one or both the bovs it would fit the issue of open at idle and lost boost. You could easily verify by boost leak testing.


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[l0lwut123]

Kit is brand new, bought it from andrew@activeautowerke in october.

Pulley is the size they put on it.

Ill have to check the adjustment screws on top of the bov's.

There is a difference in the line length between the front and rear line as the rear has the tee into it from the rail, as well as the tee into it for the hobbs, as per the instructions.




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[l0lwut123]

Tried to reply to this though tapatalk, but it doesn't seem to have posted, so if a second reply with similar answers comes through i apologize.

• I bought the kit new from andrew@activeautowerke in September/October.
• when i flip the toggle switch to off, the front one closes and the rear vents more air, Im assuming from the lack of air venting out the front one that is now closed.
  
  • with the switch in the on position both BoV's vent.
  
  
• As far as I know, the pulley is the right size, i opened the blower new in box from active when it was installed.
• ill have to check the screws, since i assumed they were properly set when they arrived since the manifold, solenoid, and BoV's were assembled when the kit arrived.
• The rear BoV line is a little longer, but that is because it has 2 tees in it, one to tee in the vacuum from the vacuum rail, and the other to tee the vacuum/boost into the hobbs switch as the instructions dictated during the install

to add another point that a friend asked me and seems like a relevant point:
the light in the car signalling low methanol and limiting the system to 7 PSI is off. tank is full.

[lisnowboarder]

With our longer post I’m didn’t quote to save space. But to your point about methanol being low I’m not sure how that matters or would effect anything psi related. On a turbo car a failsafe like that would trigger an alternate psi to open the waste gate early and bleed of psi. On a supercharger it’s all mechanical there’s is no turning it down by conventional means. Or specifically there is no turning down the psi you would see in the manifold. You could have safeguards to change timing and fuel for a safer combustion.

*if you have the tools I would boost leak test. From your interpretation your loosing a lot of boost which should show up pretty easily. For reference my car when purchased was down 4psi from improper vac lines that were pressurizing the crank case.


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