Mixed info, oil feed info needed

[OutToWinPAHC]

So I have a decent sized Garrett T3/T4 from the TA3405 family, actual part number 466159-5004 but its a t3/t4 Journal bearing oil cooled turbo. Anyhow the turbo is out for rebuild, and it was supposedly new when I got the car on trade, but right away I noticed shaft play. I removed the turbo and the seals were leaking, well just the exhaust side was.

Anyhow I am not sure what size my line is, or what brand it is to be sure, but I looks to be internally restricted. Outside looks about -4 but internally it's much smaller. Which I think may be why the turbo was no good. Anyhow I want to start fresh with the proper fittings and lines but when I search for info I get mixed results. Some say -3AN no restrictor, others say -4an with restrictor but give no size on the restriction.

So please let me know what you think is proper. It is a top mount, and the drain is routed nicely with 5/8 line aka -10AN

[Carl H]

-3 typically no restricter needed, -4 then 0.064" for journal and 0.032" for bb.

[OutToWinPAHC]

So I have to ask why no restrictor with -3 which should be 0.1875" but when using -4AN .064"?

[Carl H]

overall increase in volume of the hose, learned it that way years ago and it still holds true.
i have to run an inline restrictor on my 30r even tho it has one built in due to the -4 line.

[OutToWinPAHC]

Good info, not to figure out what I have. I think it's ebay special

[robbie2883]

overall increase in volume of the hose, learned it that way years ago and it still holds true.
i have to run an inline restrictor on my 30r even tho it has one built in due to the -4 line.

really? i'm not doubting at all. but what brought you to that conclusion? were you blowing oil out of the seals? i've been running a 4an on my gt35r for years with nothing but the internal restrictor on the turbo. ran several customers cars this way without issue too. if i need to change the way i'm doing things so be it.

[Carl H]

it may be due to my setup...but i've not had good luck with running -4 lines to turbos without the need for an additional restrictor.
on my car the oil feed is about 4" long from the block straight to the turbo, was getting oil seal blowby from the turbo without the secondary restrictor.

seems to be luck of the draw, however, as some turbos are just fine without but others will puff smoke.

[julio]

I run a 0.078" (5/64") restrictor for my Holset with a -4AN line. I installed a pressure gauge post restrictor and tried several different sizes before I found one that would keep the oil pressure to Holset's specs.

Another important factor is the manufacturer and grade of the oil being used. 10w40 may never smoke, but 10w30 may depending on the situation.