This is how I had things routed before going for a test drive once I was done with the turbo/fabrication.




During the initial test drive the hose going from the turbo drain to the scavenge pump infeed got kinked do to heat from the oil inside it. In turn my turbo seals blew, the car was smoking and I had oil in the intercooler. So after cleaning everything up really well, getting the turbo rebuilt by a Garrett certified shop, I put it all back together. They honed the turbo, replaced seals bearings (journal) complete rebuild...ect.

I also re-routed my drain from the turbo to the scavange pump, it is now a straight horizontal run of about 8". I know the pump works, and works well. I had the hose that is connected to the turbo drain disconected ,while the pump was running, I put my finger at the end and the scavange pump draws instant vacuum. The pump is brand new (Weldon) and is from a Corvette TT kit, so it was desighned to return for two turbos from a much longer distance. The turbo supply line has an oil restrictor (.065 I think) so it can't be getting too much oil.

Today after a 20 minute drive everything seemed ok, no smoke and the car pulled very nicely. I parked it in the garage for an hour ors so, lifted it and removed the first IC pipe connected to the compressor. Oil again, not much but there is oil. Oil is 5W40.


What is going on? Does the oil come trhough the seals when the copressor is in vacuum? I am really lost here, any input is welcome. Maybe a smaller restrictor? Cold start = 100psi of oil pressure on the OEM gauge with the 5W40.

 

i think any time you have a sump draining oil from a low turbo, you get some oil that will get by the seals. when the oil goes thru the turbo, it turns into a froth when it mixes with air. that in turn, doesnt get sucked out by the sump, causing oil to backup. the best setups ive seen using sumps has a small reservoir below the turbo that allows the oil to collect and liquify again before returning to the sump.

my APS single did the same thing, nothing i did fixed it.

 

Thanks for the reply, at least that makes me a bit more comfortable about it, knowing APS kit does the same. I may try a small reservoir, see how it holds up.

 

Sorry for OT but did you ever get Dyno#? I cant find ur build thread. lol

 

Any STS guys have this problem?

Jay'Z: No dyno yet, I have been pissing around with this oil problem.

EDIT: Found this, a good read: http://www.emotors.ca/Articles/147.aspx

 

The guy I bought my STS kit from had oil get in the pipes, as the intercooler had some residue on it from when it happened. He said it was because the oil drain was not perpendicular with the ground; it was clocked slightly off. I made sure that everything was aligned right, and I haven't seen a drop of oil in any of my pipes.

It's hard to tell in that picture, but it might be slightly off ??

 

The drain is straight down for sure, so that shouldn't be the reason. It's driving me crazy. I will do some more experimenting today, I will hook up a pressure gauge on the turbo drain and see if shows anything. It shouldn't but I will give it a shot. If for some reason I see pressure I will know that the pump is not taking the oil away fast enought. Maybe reduce the oil restictor size, something like that.

 

You could try lowering crankcase pressure to help with oil return if you haven't already addressed PCV plumbing re-routing/breather etc. See the end of my build thread for a set up that works for me.

 

Thanks, I will have a look at your build. The PCV is vented to atmosphere, so I don't think I have any pressure building up in there under boost. My return is in the upper oil pan as well, above the max oil level.

 

Ok, so on the way home from work I was thinking, how can I confirm that my scavenge pump is doing it's job. I remembered that I have a boost/vacuum gauge laying around and that's when it hit me. Put a T between the turbo drain and the scavenge pump inlet with the boost/vacuum gauge between the two ports. The idea is, if I have boost the oil pump is not pumping fast enoght if I have vacuum the pump is exceeding the oil supply. Here are the results:

The way it was riged up:



With engine off and scavenge pump on. About -15 on the gauge




While the car is running cold and the oil pressure is about 80-100psi. About -8 on the gauge, so still vacuum. This confirms that the oil is not getting through the seals to the compressor housing, do to high oil pressure. This is acutually better than gravity feed from what I have read while researching. I guess with the engine idling/low load the turbo compressor is in vacuum and it can "pull" oil through the turbo seals. This clearly is not the case here.



The way things are on the car now:



I just can't think of anythig else.

 

ill post some pics of the reservoir i mentioned. look into the compressor outlet and you intake pipe to see if oil is there, if so, theres no other place it can be coming from than the turbo.

 

Thanks, but I just don't see that helping. If the bearing/seal area is in vacuum all the time, how could the oil get to the compressor? I am going for a drive now and tommorow morning I will check it all out again.

 

it doesnt matter if its under vacuum if the CHRA is full of oil that isnt being drained properly. the oil has to go somewhere, and it will. if there is oil in your inlet and outlet right at the turbo, its got to be coming from the seal. it cant be traveling backwards from the engine to the turbo thru the intake tube.

 

Oh for sure, it can't possibly be comming from anywhre else but the turbo seals. I just got back from a drive, the car runs awesome and it doesn't seem to be smoking. Tommorow I will take the the IC piping off and see what the story is on that side.

I wonder how APS ST kit get away with it. I know it's a BB turbo but it still needs oil:

http://www.airpowersystems.com/350z/...ery/route1.jpg

But I guess you know better than me that it too in it's original form has problems simmilar to me. Look forward to seing your modification. My only problem with having a small tank is space. If I go any lower I may be too close to the ground. I am sure I will figure something out. The original plan was to make a small catch tank, but again the idea got shelved do to height of the turbo.

 

i would just clean my IC and pipes out every few months, there would literally be 1/4 inch of oil in the bottom of my IC. the BB turbos need really small restrictors, they dont need as much oil since they use water for cooling too. here are a few pics that i found back when i was having this problem.

i think the SFR TT kit uses a Mocal sump but they use a collector reservoir too.

 

BUMP

Any other suggestions?

I drove the car around plenty this weekend and today got back under it to see if the oil is still getting to the IC piping. It is. When I took the drain flange off some oil came from the rubber hose but if I put my finger up in the turbo drain line it is farly dry. This tells me that the oil is being taken away by the pump.

My ONLY other theory is if the oil restrictor is too large, and the oil being delivered to the turbo cannot go through the journal bearings fast enough, resulting in high oil pressure inside the turbo. This in turn cause the seals to leak oil.

Any thought on that idea?

This is the restrictor on there now:

http://www.atpturbo.com/Merchant2/me..._Code=ATP-OIL1

 

hey, I have the APS St and while my ic pipes just had a slight coating of oil, there was quite a bit of it in the turbine housing. after the winter I put on a FP inline filter/restrictor... seems to be helping with the smoke. and Tigg is right the catch tank is the solution, but its nearly impossible for us aps st guys... no space... id just deal with it, even OE cars get that sometimes, a kid with a mazda speed3 had the same shise after 13K its a turbo car. Besides that what turbo setup are your running? is it full out custom? or and APS moddified one? I like how the turbo is on the passenger side, never figured out why aps didnt put it there, no steering shaft to go around, and more space... anyways man, if you wouldnt mine sending a few pix of the setup id appreciate it, and gl with figuring it out, maybe it can be addapted to to the APS st if you firgure something out. =)

 

^^Thank you for the input.

The kit is custom, I built it and here is the full build/details:

https://my350z.com/forum/forced-indu...brication.html

I will try the small tank idea to see if it works. I will report back once it's on and running, I hope I have time at work tommorow to make one.

 

UPDATE:

I ended up building a small catch tank and mounting it to the turbo drain, and there is no more oil issues. Thanks for the input guys, now the kit is flawless. More details in my build thread: https://my350z.com/forum/forced-indu...cation-17.html

The problem was when the car was parked, and not when being driven. Before installing the catch tank, I would find a few drops of oil comming from the compressor after the car sits for a few hours. So what was happening is the oil from the turbo supply line (6' long) would drain in to the turbo, and it really had nowhere to go. So with it sitting there the oil would leak through the seals and get in to the compressor/turbine.


The tank is very simple. It is a piece of 1.5" square tubing, drilled through for the flange bolts with a two pieces of tubing welded at each end. This ensures a proper seal with to the turbo. It hold 150ml of liquid (about 5 ounces)

 

Very nice setup you have there. I also fabricated my own rear mount turbo setup as well, the way I went about solving the (parked, engine off) oil issue was to have a turbo timer and set it for about 1 to 2 minutes, then wire it up to the relay that powers the scavenge pump, this way when you turn off the car, the pump will drain out all the oil thats sitting in the line, that way no oil will leak back to the turbo and passed the seals over night.