Turbo pump and VNT question

[RustyCaddy]

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/1709865655

Wonder 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.

[oblique]

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?

[fatmobile]

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.

[RabbitJockey]

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.

[RustyCaddy]

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

[RabbitJockey]

i would use boost to control the wastegate can and to operate the vanes.

[RustyCaddy]

Found a interesting post here about the wastegate can approach:

https://forums.tdiclub.com/index.php?threads/reversed-movement-push-vnt-actuators.256711/

Ebay.uk might be a good place to try to find the boost control actuator.  Forgot how much folks liked to fight on vortex

[fatmobile]

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.

[fatmobile]

https://www.youtube.com/watch?v=7hbI5rVjobo

[oblique]

some potential links here:

https://www.vwvortex.com/threads/1-6d-n-a-cr-engine-1982-turbo-build-thread.9522999/post-115990646

[chi1337]

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

[fatmobile]

 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=MtIugEqjkHk

Vacuum controlled with a dawes device

[RustyCaddy]

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

[RustyCaddy]

Okay, so it has been a while but wanted to followup.  Before doing something foolish (again!) does anyone know if tying a line into the brake vacuum pump hose, with an additional check valve, might work to regulate the vacuum control for a VNT-15 on a motor that is also fitted to a turbo pump?  Haven't seen a write up mention this so it is probably a dumb idea-not like that has stopped me before on other endeavors but wanted to check
Thanks!

[fatmobile]

If you want it to be vacuum controlled, then that's where to get the vacuum.
 There is sometimes a small manifold in the hose, near the vacuum pump,
that has a few barbs to connect to.
Doesn't need to be a big hose.