I don't think thats the problem. As long as your return line is bigger then the intake line you should be fine. I'm running -8an and the guy that made my flanges for me said he could machine the AN fittings for better flow, which I may have him do. Here is a pic of my setup you can see the flare inside the hose. I had to go with -10 to -8AN because that was all that was available locally... Same goes for the rubber hose. Your setup is much nicer then mine.

 

hmm well your setup is making me think it's something worse

True that the inlet is small and the return is the same ID as stock so maybe it's a bad rear seal. The guy called it something like Piston seal/clip or something.

 

What size is your inlet oil supply? The reason I ask is that I have been told by some experienced turbo guys that too much oil supply can cause failure of a turbo, just like not enough.

IN fact, for my custom turbo install, I was instructed to run a restrictor pill in my oil supply line. Most people run -3 or 4 an for supply, and -10 or -12 for drain. I could only obtain fittings for -6 supply, but I did get -12 drain. I was told -6 flows more oil than the turbo can handle, and thus a restrictor pill is necessary. This is a fitting with a smal hole bored out in it, put in one of the hard fittings with threads. I had sizes between .035 and .060 recommended for my application (hole ID in restrictor).

Here is a cut and paste from an email convo with my turbo supplier:

BE VERY CARFUL!! You went with 12AN for the drain which is perfect, but you need to run 3 or 4 AN for the supply line or your gonna have to run a restrictor. You can tap the 1/8" adaptor and screw in a set screw..... then drill out the set screw (I believe it should be a .03~.04" ) Do a search on the forum for this, some people even use Holly carb jet screws for this. If you run straight 6AN line as a supply your turbo will blow oil and smoke like a **** and possibly damage internal bearings (thrust set).

Here are some manufactured restrictors, they may be a little big, the rotary runs high pressure, I'm assuming your have a 85 psi relief in your engine.

http://www.sr20forum.com/showthread....threadid=35577

http://www.atpturbo.com/Merchant2/me...egory_Code=OIL

Ya man....too much oil is baaaaaadddddd for a turbo. It'll blow right past the seals and you could damage the thrust bearing in it also (aside from embarassing smoke and sending oil all in your intercooler and entire intake track).

3/16" = .1875".. going by everyones recommendations of .035~ .055 I'd say the hole is too big. The problem is the turbo bearing sees oil, then its disscharged into your drain line, but it should only be gravity pulling the oil out the turbo, if theres too much pumped in there pressure will build up and blow into your turbine and compressor housing making a mess. If the pressure is really high it can cause your thrust bearing to move off the CHRA housing and starv itself were it makes contact with the thrust colar. Get -3AN (preffered) or run -4AN (acceptable) or get / make a restrictor. Do a search on the single turbo forum to get a feel of what I'm talking about. Sinse you have a large -12 AN drain, -4AN feed will be fine. Also cause the large drain, you could go with the larger restrictors (.05 maybe).

 

The system itself is low pressure it's not driven entirely by gravity...

 

The inlet is the stock tubing! that's the odd part. I also cleaned out the parts before I installed them so I know they're clean.

 

We are running stock oil feed tho which is -4 I believe. Which means -8 or -10 should be fine. -10 is the same size in the bottom of the stock turbo.

 

The turbines spin fine too. The guy said if it failed it would have touched the sides but the play is perfect?!

Well I am trying to find some way to get back onto the side of town where they and my turbo are so I can have them check it out.

Currently I'm stuck riding a bicycle to work and the turbo and guys are 30+ miles away

 

I have the same problem with my rebuilt t78,oil seeping down between turbine and centre section.
I have -12 return going straight down and -4 feed .
The rebuild was complete and upon disassembly looks like it was done properly.

I'm gonna try another piston ring seal,even though this one is new. This is the only place it can come from.

A word of advice: DO NOT drive your car with this condition, the oil seeping onto the turbine housing can ignite due to the extreme heat the housing throws out and put you up in flames in no time.

BTW, if your crankcase is building too much pressure ie, blocked breather then this can cause the turbo to push oil out, check that aswell.

 

Thx for the advice

I've already pulled the turbo and it is sittin on my counter until I can go to the turbo rebuilder and see what they can do.

I know it is the turbo itself.

It has been sitting in a box for the last week and when I pulled it out today oil was all over the housing and the exhaust fin so I know it's a bad seal there.

 

I sent mine back, the verdict was mixed. He stated that there was no seal failure but there was oil all over the hot side but none on the intake side. He said that it looked like it was due to too much oil pressure inside the turbo. I'm taking my AN fittings and running to a -10an all around and then having a machine shop machine the inside of them for better flow. The machinist said he's heard of this before and has seen this work well. I'll post my results in a few weeks.

 

Your turbo failed too, mike?

 

woops forgot to update this thread.

So I took it to the turbo guys.
They pulled it apart and everything was perfect.

Now here is one tip on our turbo's.

Hitachi's have a built in restrictor pill.

Most turbo's have an inlet inside the cartridge the size of a pencil's eraser.

My turbo guys removed it and detroyed it as they were pulling it out to clean behind it.

They said they have not had problems w/ ppl doing thios before.

They guessed due to the high pressure it needed it.

So I bought some 3an hose and a 1/8 adapter to restrict the oil flow in.

So far it has not smoked bad(A little which I believe is due to the new engine)

 

SO, in fact, the problem was too much oil flow, from lack of a restrictor pill? Good info.

 

MOTHER ******!~!! I bet thats the same goddamn problem i'm having... Jesus THANK YOU FOR THIS INFORMATION.


My engine will finally run again.
Thank you, pardon the cursing, i'm friggin happy. Goddamn.

 

Okay, so Im lost. Digitech had the published problem with his turbo, but Mike, you never stated you had a problem with yours. We're missing some info here man.

And yes, I believe this is the issue I mentioned several posts above, too much oil flow into the turbo.

 

Well, I pulled my turbo due to oil seeping out around the back plate where the wastegate is on the turbo, the exhaust side of the turbo was COVERED in oil, but the intake side was very clean. So I was scratching my head, pulled the compressor housing off and there were two stripped bolts ... odd.. but that wasn't the issue. So I called Jeff at turbo auto, informed him of the problems and sent the turbo back to him for some diagnostic work. He said he couldn't find anything wrong with it, replaced the garrett compressor housing with a turbonetics one and shipped it back (i've yet to receive it, i need to go pick it up at UPS tommorow morning). He left me a message regarding something specific I didn't catch it the message completely, it was garbled on my answering machine when he called so he may be referring to this issue. We will find out tommorow I suppose.

 

biggity bam, turbo is back, pics are in. It's bling bling.

He said he couldn't find anything wrong with it, replaced the garrett compressor housing with a turbonetics one and also replaced the center cartridge with a different one. He stated the restrictor pill had not been touched. All the screws in place but..... He left the back plate off, no biggy it's in the mail before I even called about it. Go Jeff. Excellent customer service from Turbo Auto of Nashville 615-383-6242. I'm going to try running the same oil feed with a larger oil return... much larger. -12 possibly.

 

Can you tell if you have a restrictor pill on a stock setup? My 7 is smoking like a freight train and it's oil coming from the turbo which I just rebuilt and I didn't see anything restricting oil flow. And if I don't have one, how do I install one?

 

hmmm. An update on my setup.

IT'S STILL BURNBING OIL!!!!!!!!ARGGGGHGHH!!!!!!!!!

I've got to pull the UIM off to work on some stuff so I think I'll be doing some other things there too.


The only thing I can do now is to remove the 90 elbow I have in my return line and get a 45degree one to hopefully make the oil flow out of the turbo better.

Other than this I can only assume there is blowby due to it being a rebuild and the crank case is not venting as it should.

 

ALOT of people have this problem. if the crank case is not vented it will smoke.