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      09-16-2021, 09:01 PM   #1
Gosuu
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F30 2015 335 xi Vacuum cut out

Hello all, I need help.. I got this thing https://www.ecstuning.com/b-ecs-part...20923ecs01~dk/

Cut out vacuum actuated, I installed everything but I have a problem.. I can't get enough vacuum from the map, I got a boost tap on the map but it's not enough.
Any one got a idea how I can do it.. Yes everything works fine we tried to open it with a vacuum pump.

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      09-16-2021, 11:18 PM   #2
thejeremyman9
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How much vacuum does it need?

You are only going to have positive pressure post-turbo when under load and you aren't really going to ever have vacuum pre-turbo unelss you have a massive intake restriction... so the MAP isnt going to be a vacuum source when you need it.
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      09-17-2021, 01:20 PM   #3
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Requires only ~8in/Hg of manifold vacuum to open exhaust valve

Vacuum actuated, requires post-throttle body intake manifold vacuum source for activation
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      09-17-2021, 05:03 PM   #4
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Quote:
Originally Posted by Gosuu View Post
Requires only ~8in/Hg of manifold vacuum to open exhaust valve

Vacuum actuated, requires post-throttle body intake manifold vacuum source for activation
IIRC the highest vacuum i have ever seen pulled on the MAP is -0.7psi, whereas your cutout requires ~4 psi, and that's only at low/no throttle (i.e., idle or decel). If you want the cutout to open under WOT/boost, you are never going to get it to work by connecting post TB which you necessarily have positive pressure and not vacuum at the MAP under those conditions. A vacuum-actuated cutout is just not correct for this application with where you are trying to tap into
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      09-17-2021, 10:58 PM   #5
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You have any idea where I can get enough vacuum to open it? I heard about vacuum pump.

Thanks
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      09-18-2021, 07:27 AM   #6
pshovest
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N55's have an engine driven pump that provides vacuum for the brake booster and evacuates the crankcase. Be sure your connection is reliable so you don't loose your brakes unexpectedly.
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      09-18-2021, 01:33 PM   #7
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Quote:
Originally Posted by pshovest View Post
N55's have an engine driven pump that provides vacuum for the brake booster and evacuates the crankcase. Be sure your connection is reliable so you don't loose your brakes unexpectedly.
Yeah, but is this going to provide vacuum when he wants it and no vacuum when he doesnt want it? I am not entirely sure how this varies with engine load/rpm/etc
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      09-18-2021, 03:26 PM   #8
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Quote:
Originally Posted by thejeremyman9 View Post
Yeah, but is this going to provide vacuum when he wants it and no vacuum when he doesnt want it? I am not entirely sure how this varies with engine load/rpm/etc
I assumed the kit came with a solenoid and switch to open on demand by user. If it doesn't, ECSTuning should be able to provide one.
EDIT: Scroll down the link to item 3. It's another $50 or$100.

Last edited by pshovest; 09-18-2021 at 03:34 PM..
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      09-20-2021, 12:21 AM   #9
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Quote:
Originally Posted by pshovest View Post
I assumed the kit came with a solenoid and switch to open on demand by user. If it doesn't, ECSTuning should be able to provide one.
EDIT: Scroll down the link to item 3. It's another $50 or$100.
Gotcha, it just sounded like OP was trying to get this to open under vacuum at WOT, which is the opposite of what tapping into the MAP would do.
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