Turbo Oil Feed Line Restrictor - What size?

[FWombat]

I've had oil leakage problems on multiple 14B turbos now, all of which seemed to be in good condition. After some thought and troubleshooting, I think the problem is that I'm feeding them oil with an unrestricted -4AN line from just after the oil filter, and the oil just can't drain out fast enough.

I've found a few old threads where the use of an inline restrictor was discussed, but couldn't find much in the way of size recommendation. Some searching of archived Honda forum threads leads me to believe I should be looking in the neighborhood of .06" (~ 1/16") Anyone have experience with restrictor sizing? Ideas?

Thanks!

 

[Mackzero]

They do this on the VWs I have seen, but I have not seen this done with the DSMs. I am sure it is done, just haven't seen it.

 

[Budget90GST]

Just try to find a factory oil line. The restrictor is on the banjo line from the head. 1/16" sounds about right, it's been a while since I saw mine.

 

[yo2001]

there is a restrictor in the CHRA of Mitsu turbo.

 

[FWombat]

Can't use a factory line - this 14B is actually not on a 4G63 (it's on my 3000GT). On my car, I just have unrestricted -4AN line going to the 14B, and it seems to be giving too much pressure. My car has a fresh oil pump and great oil pressure...too great for the turbo, it seems.

Doing lots of old thread reading, it looks like early model DSMs took the turbo oil feed from the head, where oil pressure is relatively low. After a couple of years they switched to taking turbo oil feed from just after the oil filter, but when doing this people have said that the fitting they used to connect the line to the filter housing is a restrictor.

Anyone know how big the stock feed line orifice is? Or the size of the orifice on the filter housing? Just trying to get a ball park of how bit a restriction I should try creating.