Author Topic: VNT turbo (Read 9690 times)

foxracer1 · « **on:** March 04, 2007, 04:23:13 pm »

I know there are thousands of threads about these but none of them really talk about rebuilding them. A friend of a friend, (you know how that goes) said they have a vnt manifold/turbo that he will sell for for the cost of shipping plus $50. So i ask whats wrong and... the dealer threw a new turbo at his moms car because of a fault code. He said it worked before they replaced it. It didn't fix the problem so they threw more parts at it and fixed the problem later on. He said the "wastegate is stuck" I'm pretty sure its a VNT because its off an 2001 jetta auto TDI. So i feel the vanes are coked up. He also said there is some shaft play but thats all he said.

So can these be rebuilt realtivley easy? If so when i have it apart could i have the manifold/turbine housing, vanes, turbine wheel, compressor housing, compressor wheel, ceramic coated? anything else? I would really like to prevent heat soak in to the intake tract.

jimfoo · « **Reply #1 on:** March 04, 2007, 05:31:16 pm »

As far as I know, they can be rebuilt. I remember seeing a site where someone also had coked up vanes, and it cleaned up well. I personally wouldn't spend the money to ceramic coat it. VNTs are fairly free flowing. Just get a good intercooler.

Benjamin · « **Reply #2 on:** March 05, 2007, 01:39:51 am »

there are three important things in my opinion,
the first one is the play on the shaft like every turbo, "much or less" play is just a word... :wink:
sometimes the vanes stop moving becouse of the dirt from the black smoke, if you clean it, its good again
the last thing is the (most of the times vacium controlled) actuator, they get stuck, but you can rebuild it as well, alltough its not worth it.

my experience in vnt turbo's, after you unbolt the 6 bolts (sometimes more), its not easy to take the turbine off.

i think you allready readed about reclocking (and maybe 4 new drills), to rotate the oil drains in the right direction.

Greetz, Benjamin

foxracer1 · « **Reply #3 on:** March 05, 2007, 07:11:26 am »

Thats what i thought about the play and the vanes. Are these ball bearing turbos? I really just want to have the manifold coated to prevent it from transfering heat to the intake.

Benjamin · « **Reply #4 on:** March 05, 2007, 12:56:49 pm »

Quote

Thats what i thought about the play and the vanes. Are these ball bearing turbos? I really just want to have the manifold coated to prevent it from transfering heat to the intake.

go for a good IC instead of coating, you can go for a cheap plate also between those manifolds, but i think there's not gonna be a big difrence.

BB turbo's always have a "R" in the name, like a GT28RS...
as far as i know there are no OEM VNT turbo's with BB.

Greetz, Benjamin

HarryMann · « **Reply #5 on:** March 12, 2007, 12:35:13 pm »

Make a s/s sheet heat-shield for the exhaust manifold, like the JX 1.6 vanagons had (mild steel). 1 ~ 1.2mm s/s is about right to work with provided its not a very hard grade.

This will reduce most of the radiant heat, and also keep heat in the exhaust manifold where it can do most good.

HarryMann · « **Reply #6 on:** March 12, 2007, 07:27:36 pm »

Happy to send some templates over, but this will give you a fair idea...

I'll put some better pics up if you like. Needs a few curves in strange places but basically 3-pieces, top & bottom much the same, needing cutouts to get the manifold nuts on. I shall pop-rivet top/bot plates onto the main side plate with steel or monel pope rivets, but could be screwed I suppose.

jtanguay · « **Reply #7 on:** March 12, 2007, 08:49:07 pm »

hmmmm that heat shield would be great!

to prevent any heat soak into the intake manifold, why not get it ceramic coated? best option imo, and use the exhaust mani heat shield.

The only time i think coating the exhaust manifold would be a good idea, would be with an equal length manifold like dave from PP is creating. Otherwise you will have one cylinder that will be getting all the heat and probably cook it!

HarryMann · « **Reply #8 on:** March 13, 2007, 09:38:02 am »

Yup, s/s not only is highly reflective when polished, but also has a lower thermal conductance than mild-steel...

and yes, very difficult coating the inside of such a rough casting as the std. manifold I would have thought - reliably.

foxracer1 · « **Reply #9 on:** March 13, 2007, 06:35:48 pm »

I do have a piece of S/S so i might go that route. I just got pic of the turbo. The center section is busted. The guy tried to dismantle it and broke it some how :evil: :x . So does any one have a VNT 15 center sec.?
Or even a VNT 17 maybe with a brokin turbine?

Ok so Photobucket is being stubborn and i can'y login so ill ave to get back to you on the pics.

foxracer1 · « **Reply #10 on:** March 14, 2007, 04:26:26 pm »

pic 1
pic 2
pic 3
pic 4
pic 5
Poor VNT! :evil:

jimfoo · « **Reply #11 on:** March 14, 2007, 09:24:33 pm »

Looking at pic #3 I see a GT1749, so you actually have a VNT-17, probably
on a VNT-15 center and manifold.

foxracer1 · « **Reply #12 on:** March 15, 2007, 02:01:05 pm »

Really? Well i see that now. It is said to be out of a 99 jetta tdi auto. When i get it i'll look closer. So this is like yours. VNT 15 turbine/VNT17 compressor?

jimfoo · « **Reply #13 on:** March 15, 2007, 04:48:42 pm »

Yep, like mine except mine has the k-14 manifold adapted to the 17's exhaust housing.

xtremitys · « **Reply #14 on:** March 17, 2007, 03:35:55 am »

i just joined up here purelly bout the VATN , VTN, VTG , etc

I just bought a good GT 25 VTN actually- i'm in Christchurch , NZ . It has the vacuum controller aswell , its complete . but thinking about selling it as i need bigger . I have a 89' SWB toyota landcruiser 4x4 and soon building a tough 4.1 ltr turbo diesel with custom internals , etc , was going to run a 2 X GT25 VTN's - but having a look around i see they are rare as hens teeth and kinda thinking i won't find another . I have seen bigger ones more suitable ( GT30 - 35 ).