Putting a VNT 15 on a Rabbit

Upgrades to the 1.5, 1.6 and 1.9 engines that make them go farther or faster
ibizz
Cetane Booster
Posts: 34
Joined: Wed Dec 29, 2010 8:06 am

Re: Putting a VNT 15 on a Rabbit

Post by ibizz »

il try to put mine working this week

il just change the waste gate actuactor por 1 of gt 15
and lets see
Fatmobile
Global Moderator
Posts: 7474
Joined: Wed Oct 30, 2002 10:28 pm
Location: north central Iowa

Re: Putting a VNT 15 on a Rabbit

Post by Fatmobile »

Sooo I upgraded my vane controller so it isn't under the turbo where I can't see it,..
and so I'm pulling up/perpendicular to the vane controller lever.
I'll take some pics of the new setup and get them posted
This is with it floored:

The lever is pulled, which shoves the rod downward until the boost comes on and moves the lever pivot point forward, pushing the rod back up.

At idle the vanes are open, with the rod pulled upward.


It works alot like my other setup but doesn't have 2 arcs working against each other.
Instead having a rod pulling upward.

It still needs some refining.
The rod coming from the pump has an Andrew Libby Inspired Safety Device (ALISD)
in case the vanes stick,.. I can still let off the fuel.
I'd like to use a lighter, bent rod to go from the pump to the gizmo and use a spring setup much like what is already on the pump to give way if the vanes stick.
'91 Golf gasser converted to a 12mm pump, M-TDI.
'84 1.6TD Rabbit with a VNT-15 turbo, still setup to run on vegetable oil.
'84 GTI with 1.7TD pistons and intercooled.
2003 TDI wagon
2000 TDI Jetta.
Fatmobile
Global Moderator
Posts: 7474
Joined: Wed Oct 30, 2002 10:28 pm
Location: north central Iowa

Re: Putting a VNT 15 on a Rabbit

Post by Fatmobile »

It's working pretty good in the midrange,
going down the interstate at 65mph boost is at about 3psi and egts are at or below 700.
I'm not sure what optimal would be, maybe a little more heat, less boost less backpressure.

If I floor it on the interstate it will boost past 20 so I'll have to tune that down
and I would like to have more boost when accelerating from a stop.

Having the manual controller taught me alot about where vanes should be set when.
I'd like to have max boost for taking off from a stop,.. the first few seconds.
It sounds better: keeps it quieter and has the turbo whine.
Also provides the air I need to get rid of the puff of smoke and turn it into power.

Higher RPMs with the vanes closed cause too much back pressure.
I can feel the car "relax" and take off when the vanes are opened back up.
So after the first few seconds I'd like to have it play around in the midrange of the vane setting keeping the EGTs around 800.

When floored it would be nice to have it jump up to 18psi and stay there.
'91 Golf gasser converted to a 12mm pump, M-TDI.
'84 1.6TD Rabbit with a VNT-15 turbo, still setup to run on vegetable oil.
'84 GTI with 1.7TD pistons and intercooled.
2003 TDI wagon
2000 TDI Jetta.
Fatmobile
Global Moderator
Posts: 7474
Joined: Wed Oct 30, 2002 10:28 pm
Location: north central Iowa

Re: Putting a VNT 15 on a Rabbit

Post by Fatmobile »

Here's some pics of my most recent contoller:
Image

Image

One of the nice things about it is if you give you put it to the floor it shoves the vanes all the way open.
I can feather it to keep the boost below 18psi.

I'll take a pic of it in place.
'91 Golf gasser converted to a 12mm pump, M-TDI.
'84 1.6TD Rabbit with a VNT-15 turbo, still setup to run on vegetable oil.
'84 GTI with 1.7TD pistons and intercooled.
2003 TDI wagon
2000 TDI Jetta.
BGA
Glow Plug
Posts: 6
Joined: Tue Dec 13, 2011 9:51 am

Re: Putting a VNT 15 on a Rabbit

Post by BGA »

Any pics of the device installed?
"The rod coming from the pump has an Andrew Libby Inspired Safety Device (ALISD)" pics?
Fatmobile
Global Moderator
Posts: 7474
Joined: Wed Oct 30, 2002 10:28 pm
Location: north central Iowa

Re: Putting a VNT 15 on a Rabbit

Post by Fatmobile »

Yeah, I've been meaning to get some pics of it installed, thanks for the kick in the butt.
I did try changing the spring in the stock boost can.
The old one was about 7/32" wire and was to stiff. The new one was about 5/32" and too weak.
I'm thinking a spring with 1/8" wire will work great depending on the length.
'91 Golf gasser converted to a 12mm pump, M-TDI.
'84 1.6TD Rabbit with a VNT-15 turbo, still setup to run on vegetable oil.
'84 GTI with 1.7TD pistons and intercooled.
2003 TDI wagon
2000 TDI Jetta.
Fatmobile
Global Moderator
Posts: 7474
Joined: Wed Oct 30, 2002 10:28 pm
Location: north central Iowa

Re: Putting a VNT 15 on a Rabbit

Post by Fatmobile »

Here's some pics of the newer Rabbit VNT-15 controller.
The last one I posted/built was still a prototype.
It worked great but the holes wallowed out.
So for the new ones I use small sealed bearings.
This picture gives an idea of how the bearings were mounted:
Image

This picture shows how it's connected.

Image

The allen head bolt is where it pivots.
This is bolted solid to something.
The rod going down is to the turbo.
The connector from the left comes from the boost can
and it's the pivot for input coming from the top of the pump.
Basically the throttle position sensor,
which connects to the hole in the top of that lever.

This one is a pusher instead of a puller design.
Which means the rod coming from the injection pump pushes the lever instead of pulling it
as the accelerator peddle is pushed.
As it is pushed to the left the rod to the turbo is pulled up and the vanes are opened.
As boost comes on boost is backed off even more.

Here's a view from the back of the same controller:
Imagevntcontollerback by vwfatmobile, on Flickr

It shows one of the spacers that were made from tubing to get the offset right

I thought I had some of the M-TDI controller but looks like I haven't taken those pictures yet.
'91 Golf gasser converted to a 12mm pump, M-TDI.
'84 1.6TD Rabbit with a VNT-15 turbo, still setup to run on vegetable oil.
'84 GTI with 1.7TD pistons and intercooled.
2003 TDI wagon
2000 TDI Jetta.
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