Vnt-15 installation, slowly but surely.....almost

[rabbitman]

(bangs head on desk)....why can't I post? I have lots of questions but when I write it down it won't post, aaarrrgg

[rabbitman]

aarrrg. I can write anything but what I need to say, (lays twitching on the floor)

[rabbitman]

Use lubricated 80 grit paper on something flat to smooth all the mating surfaces until they are flat.  Use a light smear of ultra copper on assembly.  The oil is from your crank vent.  It appears that you don't have an oil separator, but just a normal n/a valve cover. 

Andrew

You mean to flatten the intake AND exhaust surfaces?

Correct, how important is an oil separator? duh, I guess I can tell by all the oil in the intake .

[rabbitman]

Man I can only write little short stuff!

[rabbitman]

One little question, will the turbo leak oil into the intake hose worse if I run it hard before the oil is all the way up to temp?

Andrew, have you actually wired the vanes fully opened and verified that a 1.6 will still make boost?

I thought of that with the vanes fully opened it "could" be a very effective "wastegate". Just because the boost can fully extends at 15psi during testing out of car doesn't really mean the vanes have opened completely, it only means they've opened enough to regulate it to 15psi.

I edited my question so hopefully it makes sense now.

[rabbitman]

Thanks Andrew, looks like I'll be pulling parts off again and improving the gasket surfaces.

Yes, I have run a VNT17 with the vanes fully open on a 1.6 and it will easily put out 15+ psi.  Without added wastegate control it's not possible to regulate boost lower than that.

So you mean the only way to not go over 15+ is by backing the smoke screw out or letting off the go pedal ?

I'm not trying to ask annoying/too many questions I just want to understand all this, (and get my car back on the road )

[rabbitman]

This is were I think I was loosing exhaust pressure, I added the nonmatching bolts, the unbolted holes were next to each other before.



The turbine, looks fine to me.



The PO mustuv cleaned compressor wheel.



I thought I found a veerryy small leak all the way around this flange but I think it was just boiling the soapy water, you can also see where my thermocouple goes.



I put gasket sealer on the intake mani/head so that BETTER not leak, I'll also be putting it on all the turbo sealing surfaces.

The shaft has a small amount of side to side play but I think it's fine.....or maybe that's another reason why I get oil in the intake .

EDIT: Seems to me if this was leaking there would be black leak marks outside the gasket area, the gasket has a plenty big hole in it, barely small enough actually.

[rabbitman]

I'm at a complete loss,

I removed the exhaust mani and turbo and checked/cleaned all mating surfaces, put ultra copper on everything and I even took the vanes out and made sure nothing was out of place.

 I get a huuuuuge cloud of black smoke and about 3-4 psi boost with the vanes wide opened. I didn't put the DP into the stock exhaust this time either, so the exhaust is a short 2.25", and exits in front of the shifter.

Can you guys who've installed these hear the turbo at all times? I can hear it at idle w/ the vanes opened real easy then as I push the go pedal it gets too high for my ears to hear. With full power on I can't hear it at all.

I'll go blow compressed air into the intake mani now and see if there is a leak, I doubt there is since I got 13 psi vanes closed.

I'll post what I find.

[rabbid79]

Hi, I confess I haven't read every post in this thread, but it strikes me from some of your latest pictures that the clearances between the turbine and compressor wheels and their housings is way too large.  I would think that all of the boost and exhaust gasses are slipping past the wheels.  This could easily explain the lack of boost.

[rabbitman]

Hi, I confess I haven't read every post in this thread, but it strikes me from some of your latest pictures that the clearances between the turbine and compressor wheels and their housings is way too large.  I would think that all of the boost and exhaust gasses are slipping past the wheels.  This could easily explain the lack of boost.

You have a good point, I have never had a turbo before and I've never had the chance to study one so I didn't see that as a problem.

I wonder what the clearance is supposed to be?

Anyways I just checked for intake leaks and there are none, the hose going from turbo to intake is rather stretchy. I blew 20psi into the intake and it slowly leaked out around the rings, not what I'd expect a leak to do. Here's a pic of my stretchy hose:


I don't think stretching can affect boost though, might just cause a bit of lag is all.

I'm gonna surf the web and try finding the clearance limits I'll post my findings.......

P.S. Don't laugh too hard at my intake hose

[rabbitman]

I did discover one interesting bit, when I drove it with only the 2.25" DP the turbo spooled MUCH faster. Even at idle I could hear it and a tiny blip of the throttle had it singin'.
Also, with the vanes wide open, max boost was 4psi and after I reconnected the rest of the exhaust (1.5") max boost went down to 2psi and I got very little whine at idle.

So after I fix my boost problem I'll for sure get a 2.25" exhaust all the way back .

[rabbitman]

Yup, freeflowing exhaust is good.  Still, if your wheel to housing clearance was correct in your turbo you'd quadruple your max boost with the vanes fully open. 

Yeah, fixing the clearance is definitely next and then a big exhaust, I almost got burned out pullin' the turbo so much so I'm just gonna drive it for now.
I have some other projects that I need to do first too, nothing very big just stuff I've been putting off.

[rabbitman]

Update: The new prothe center section fixed the clearance problem but not the lack of boost problem. With it I got 1-2 more psi.

Yesterday I took off the whole exhaust system from the DP back (first time with the new turbo center), very loud and droning, 5 psi max revving up to 4700rpm floored with some smoke, EGT's quickly climb to 1250F and that's when I back out.

Before I installed the turbo the egt's could hit 1150F at the highest and with plenty of smoke. Since the install I've turned the fuel down because it got to hot.

The funny thing here is with the vanes closed I can get 10psi just revving it in neutral, that's definitely higher since I put in the new center.

So could someone varify or set me straight on this? The AFN TDI made 110HP and the ALH made 90HP, both with the VNT-15. The only difference is the ALH had the US spec turbo and the AFN had the euro turbo with the separating mani. So I wonder if the A/R has something to do with it?

The other thing I've wondered is if the euro spec vnt can open it's vanes more for a more free flowing system when decelerating? If this is the case then I'll never get good boost untill I hook up a control system.

Sorry this is so long.......

[Rabbit on Roids]

if there was air going through the turbo and it was spinning, it should have been boosting. when i bought my audi, it had soo many exhaust leaks that i thought for sure that the turbo wouldnt even spool, but once i got it revved up a little bit it would still spool a little bit, not much tho. 4 of the 5 manifold gaskets were blown out bad and the gasket behind the turbo was bad.

[rabbitman]

I've been driving the last few days with only the DP and the vanes wide opened, the turbo is very loud. It spools up fast and the loud, easy-to-hear whistle is out of hearing range before the guage starts climbing.

Can you hear the whistle at full boost?