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Turbo pump and VNT question
by
RustyCaddy
on 20 Sep, 2023 12:23
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Have been wondering about this detail for a while and first off i apologize for the probably stupid question.
If i understand this, a VNT 15 is running off of manifold vacuum and the actuator servers to open the vanes while the sort of pump on a 1.6 TD is enriching the fuel mix according to intake manifold boost. The two approaches are not used together, probably for a lot of reasons. Maybe i am misunderstanding parts of this or misunderstanding everything.
Got to thinking of how a hydro aspirator creates a vacuum on a 3rd port. Saw this:
https://www.ebay.com/p/1709865655Wonder if there is enough air pushing from the intake manifold in an idi to create enough vacuum to move the actuator on a VNT?
Anyone try something like this? Is there any point in even trying
If there might be gains am thinking of experimenting. Thanks in advance for your helpful and/or critical comments.
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#1
by
oblique
on 24 Sep, 2023 12:22
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Surprised no one has chimed in but I think on the ALHs the N75 is involved somehow in reading manifold pressure and applying vacuum to the actuator...I think this must be done electronically w help of ECU, taking into account speed, rpm, etc.
I think fatmobile was contributing to a thread on vortex about this.
Did you get the pump installed yet?
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#2
by
fatmobile
on 25 Sep, 2023 13:08
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Right, along with someone called fastnradford,.. or something like that.
He has a VNT-15 controller on his M-TDI that uses vacuum.
I'm not real sure what a hydrasperator is but it sounds like it works like the thing that grabs some fertilizer as the water flows past in a hose.
Or a sandblaster grabs sand as air passes by.
I don't think you are going to get a high vacuum from the air passing into a diesel intake or airbox.
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#3
by
RabbitJockey
on 26 Sep, 2023 14:45
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that is interesting idea.
the terminology that would help you research this would be the venturi effect or entrainment.
you could definitely create enough vacuum this way but you're only going to have it when the engine is flowing enough air to pull a good vacuum on what ever venturi port you would devise. it could be finicky to tune but without trying it you really can't say.
if i were trying to run a vnt turbo on a mechnical engine, i think i'd just use a wastegate can to operate the vanes, just to keep it simple. there are better methods but i think you'd still be ahead of a wg turbo.
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#4
by
RustyCaddy
on 27 Sep, 2023 00:40
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Thanks all for the input! Gives me a lot to think about, especially the wastegate can. Will see how much vacuum that will pull. Have a chance to buy a clean but used OEM VNT15 which seems the optimal choice but also have a rebuilt pump so would like to somehow work those in together.
May just experiment with the venturi approach first and then separately a wastegate can, pretty low cost for either.
Oblique, haven't installed it yet. Need to let go of my NA pumps so am resealing and running each for a couple of weeks to make sure they are good before trying to sell them off. Will checkin when its installed
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#5
by
RabbitJockey
on 27 Sep, 2023 11:50
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i would use boost to control the wastegate can and to operate the vanes.
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#6
by
RustyCaddy
on 28 Sep, 2023 00:25
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#7
by
fatmobile
on 28 Sep, 2023 00:29
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I took the stock vane controller and converted it to run on boost instead of vacuum.
If you need a venturi to create the vaccum,
then you will be creating a restriction in the intake.
Like the venturi in a gasser creates a vacuum.
I don't want a restriction in my intake.
You will be real happy with a VNT-15, once you control the turbo.
Even a knob on the dash will let you use it.
Most of the time you can leave it on half boost.
Get an EGT gauge to calibrate it.
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#8
by
fatmobile
on 28 Sep, 2023 00:32
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#9
by
oblique
on 01 Oct, 2023 09:13
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#10
by
chi1337
on 16 Oct, 2023 17:53
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There's a vacuumpump on the 1.6NA (which runs the brake booster), so you already have a source for that
From what I've found is there are '3' methods for running a VNT;
1. manual (fatmobile; knob in car)
2. mechanical (like fatmobile did)
3. electronic. You can go full ECU or vntlda like vanbcguy made. For both of these you need lots of sensors; rpm, throttle position, boost. And lots of tuning.
I'm in the process of making one which only needs a boost sensor using an Arduino and N75. If you are interested I can share the sourcecode of it once it's done
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#11
by
fatmobile
on 16 Oct, 2023 19:31
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There is another controller for the VNT-15.
I think it's fastnradford (something like that) on the vortex,
he is also nathan Brame on utube
https://www.youtube.com/watch?v=MtIugEqjkHkVacuum controlled with a dawes device
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#12
by
RustyCaddy
on 18 Oct, 2023 12:28
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Thank you everyone for your posts! This is so great. Am pretty ignorant about electronic controls so the manual approaches are easier to wrap my head around. The Nathan Brame video is amazing, not sure which TDI he is running (1Z? with a Range Rover pump maybe?) so will have to check out more of his build videos
