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
Fatmobile
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Location: north central Iowa

Post by Fatmobile »

I got it going down the road,.. of course it started to rain so I had to fix the windshield wipers.
Did I mention this '79 came from the Old Volks Home, I think it's in northern California.
It was slippery out but this is how a turbo should act. Why wait until you get to 2000 RPM?
It maxes out at 12psi with it floored and at maximum RPM. I turned in the fuel screw and adjusted the linkage to push farther but that's what it gives.
There are other adjustments like reducing spring pressure against the boost can.
Shockingly fast. First Rabbit diesel I've ever driven that could get a second gear scratch, without really trying. OK, it was more of a chirp and it's wet out but they broke loose. :D
..aaand here's a picture:
imageshack sucks
Image
'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.
rabbit_man
Turbo Charger
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Joined: Fri Mar 28, 2008 12:45 pm
Location: Alaska

Post by rabbit_man »

That's sweet!! Glad to hear it's working.

What size of exhaust do you have?
Do you know if the vanes are opening all the way?
Fatmobile
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Joined: Wed Oct 30, 2002 10:28 pm
Location: north central Iowa

Post by Fatmobile »

He bought a 2.25 techtonics exhaust, with Borla and I built a 2.25" downpipe for it.
I haven't listened to anyone else drive it but I can't here the turbo from the driver's seat. :cry:
I don't know what the vane control is doing.
I want to put a camera down there and drive it to see, I don't have a position sender for it.

The boost can build:
imageshack sucks
Image

The spring is a valve spring, the spring seat is from a timing belt cover on,... this one was from a Fox.It needs to be ground down enough to fit inside the can mount bracket:
imageshack sucks
Image

Exhaust studs didn't need to be much longer:
Part# : X2813118

I've always thought the Rabbit exhaust should have another hanger, back where it bends before the axle:
"possible future image
So I installed one on this fine exhaust.
Last edited by Fatmobile on Thu Oct 22, 2009 1:42 am, edited 1 time in total.
'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.
rabbit_man
Turbo Charger
Posts: 274
Joined: Fri Mar 28, 2008 12:45 pm
Location: Alaska

Post by rabbit_man »

Weird that your turbo is quiet, I got a 2.25" DP and 2.5" with no muffler all the way back and it's loud. I can give it a blip in neutral and easily hear it wind up some :P . But the lack of boost is very depressing :cry:
Josh
Turbo Charger
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Joined: Wed Oct 09, 2002 7:30 pm
Location: Algonquin, IL

Post by Josh »

Maybe the VNT is nicely worn in, and the exhaust note overpowers the typical squeal... or Fat has listened to a few too many loud concerts, loud engines, and loudmouths over the years!

I think a feisty 1.6 under the hood is loud enough to cause hearing damage if you're exposed for enough time! I've always been a loud noise wimp tho, and would plug my ears in the back seat of a car if the radio is on. I often wear earmuffs when wrenching.
-'79 rabbit, getting parted out
-'82 quantum wagon, gutting.
-'84 rehabbed quantum TD sedan, southern rustless beauty for sale
-'82 cherry Westy from AZ
-more all the time; are they breeding?
Fatmobile
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Joined: Wed Oct 30, 2002 10:28 pm
Location: north central Iowa

Post by Fatmobile »

He took it home yesterday.
It's a brand new 2.25" TT exhaust with resonator and Borla muffler.
Far from a 2.5" with no muffler.
I think it might be too much, maybe sell the muffler and replace it with pipe and a turned down tip.

I have a 2.5" TT for my 1.5 VNT project car
I think 2.25 is enough for the 1.5 but I don't have a 2.25 right now and the the 2.5 exhaust needs to be built/mounted for the 1.7TD project eventually anyway.
'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
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Posts: 7472
Joined: Wed Oct 30, 2002 10:28 pm
Location: north central Iowa

Post by Fatmobile »

The turbo drain was built using a 5/8" compression fitting elbow:
imageshack sucks
Image
NAPA part # 7405 X10
In the car:


For the tubing I used a piece of metal AC tubing from a Rabbit, it had a slight bend that worked great,..
imageshack sucks
Image
and a piece of silicone hose. NAPA Part# H504

The plastic hose on the end is just checking the diameter of the pipe and how well 5/8" hose fits.
'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.
punkvideo81
Cetane Booster
Posts: 33
Joined: Wed Nov 09, 2005 5:50 pm
Location: New Paltz, NY, USA

Post by punkvideo81 »

Did you ever get to shooting a drive by video of this car in action?
'81 Rabbit p/u 1.6 TD
Fatmobile
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Joined: Wed Oct 30, 2002 10:28 pm
Location: north central Iowa

Post by Fatmobile »

No, I don't have a video camera.
Joe is taking another trip out west,
His master cylinder went out in southern Cali,
but looks like it is back together and on the road tomorrow.
'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.
ibizz
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Posts: 34
Joined: Wed Dec 29, 2010 8:06 am

Post by ibizz »

it works?

im trying to make similar work
Fatmobile
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Joined: Wed Oct 30, 2002 10:28 pm
Location: north central Iowa

Post by Fatmobile »

The controller seemed like it was binding,
sticking open occasionally.
I figured the controller was pushing the vane lever in toward the turbo a little hard and it was having a hard time moving outward so it could move down.
So I tried using a bent lever instead of straight,.. that didn't work.
Bound up more.

I also changed the heim joint on the end of the boost can rod.
There was no need to swivel.
It holds the lever more solid, straight.

So I have the controller tied at full boost.
I always thought the boost would stay to a safe level but I've hit 30psi a couple times.
No damage yet but I'll be putting a straight lever back on and hooking the boost line back up to the can soon.
I probably run the lever from a manual control on the dash,
instead of off the accelerator lever.
The will allow me to feel how the vanes are working and adjust boost from inside the car.
'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.
ibizz
Cetane Booster
Posts: 34
Joined: Wed Dec 29, 2010 8:06 am

Post by ibizz »

engine as running smooth ?

no problems?

how can i get tech info about my engine ?

with the number that is in head ?
Fatmobile
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Posts: 7472
Joined: Wed Oct 30, 2002 10:28 pm
Location: north central Iowa

Post by Fatmobile »

Worst problem with it now is blowby.
It's the first engine I rebuilt,.. and I didn't break it in right, I took it real easy on it.
It only has about 20,000 miles on it at the most.
It has always used some oil and had too much blowby.
The pistons are new so I'll have to rering it.
'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.
ibizz
Cetane Booster
Posts: 34
Joined: Wed Dec 29, 2010 8:06 am

Post by ibizz »

dificult to control vnt ?
Fatmobile
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Posts: 7472
Joined: Wed Oct 30, 2002 10:28 pm
Location: north central Iowa

Re: Putting a VNT 15 on a Rabbit

Post by Fatmobile »

I replaced the loose 1.5 with a 1.6 and am breaking it in.
The controller is working great.
While Joe's is still conected to the accelerator peddle, my new setup has a knob on the dash that allows me to change the vane position while driving,.. with boost still backing it off as it rises.
I haven't had much chance to work with it, always reving and letting off while breaking it in, but it does keep it from over boosting, while still reaching 18psi.
EGTs do get up to 1200 pretty easy, seems a little high,
'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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