Turbo oil drain size?

[jpdeuce]

What size oil drain hose are you all running? I've got a Canton oil pan set up for a -10 AN drain return. I'm concerned it might be too small. What do you think?

[shmoov69]

I'm pretty sure that is what mine is. no problems in the last 10 years!

[DButler]

I run -4 feed and -10 return and it seems to return just fine. I have seen some go with -8 but I wouldn't recommend it. Just make sure you keep the minimal amount of curves in the line.

[jpdeuce]

Thanks for the input. Are any of you running restrictors in the feed line? I've read that some people are actually installing nitrous jets and such to lower the flow going to the turbo. If you are then what size orifice do you use?

[DButler]

I just installed some because i was getting too much oil to the turbo. I am running I think .63 orfice. you can pick some up off ebay for like $10 each. I have heard of people using nitrous jets but i just ordered the correct restrictor.

[DButler]

maybe .063

[shmoov69]

Ok, how do you know if you need a restrictor? My new turbos seem to be pumping some oil out of one of them, but I never had any problems with the old ones over the last 10 years.

[jpdeuce]

It seems I've read some things about different types of seals but I can't remember for sure. I know I've read that some people would have an oil blow by problem and the restrictor would solve their problems. I didn't know if its something that one should not do unless absolutely necessary or if it was a good thing to do from the start. I may just try it with a -4 feed line and see what happens.

I think some people were having problems with oil drainage and this also helped them by cutting the total oil flow to the turbo. This case sounds like the root cause is the drain having too much back pressure more so than too much oil delivery. Any experts want to chime in?

[DButler]

If you are getting too much oil it will either be in the exhaust pipe or in the charge pipe. It is hard to tell from turbo to turbo. Too much oil will blow seals in the turbo. Sometimes oil drainage is the issue, but in some case you are just getting to much oil to the turbo. I would take the charge pipe off first and check it and if you have oil build up there or something then I would put a restrictor. Sometimes if you are smoking out the exhaust side this is another sign that you need one. There are a few scenarios that can cause the need for one. Just remember too much oil is bad and will blow the seals in the turbo and mess the bearing up, and all ball bearing turbos 99% of the time need restrictors.

[shmoov69]

Thanks Dave. Just trying to figure out if it needs seals or a restrictor.

[DButler]

If you have blown the seals then after rebuild you will want to go with a restrictor, if not I would recommend trying one.

[shmoov69]

Still don't understand how to check the seals. ? Or is there not a way without a teardown

[forcefed68]

-4 feed and -10 return are correct. I know precision tells you NOT to use a restrictor, regardless of it being a journal or ball bearing. I would contact the manufacturer and take names down. God forbid you have a problem, you may have some recourse.

[DButler]

Well more than likely if it has been ran for a while getting to much oil then the seals are gone but maybe not. They are going to always say not to use a restrictor, but sometimes you just have too. They will say the drain or something is not working correctly. I would take the charge pipe loose from intercooler and check it for oil residue and if it does then I would try a .63 restrictor if it still smokes or has oil in charge pipe then seals are probably shot and needs a rebuild. If not oil residue in the charge pipe then check the down pipe, could be in either, but I would start by looking in the charge pipe. If you are not a member on the turboforums.com I would recommend it there is lots of valuable info on there.

[jpdeuce]

Yeah. I just joined over there.

[shmoov69]

Thanks Dave. I am a member there, but mainly just a lurker. I may have to do a search for that there.

[DButler]

I have learned lots over there. This is a great site for certain info, but we it comes to turbos and blow through any info you need will be on the site if not you can most definitely get an answer. There is tons of info on restrictors and oil drains and much more and the blow through experts are over there.