Latecomer to holset mafia

[turbogeek87]

I have wanted to do this for awhile, but it was only just this past year that I have had 1) a place to work on the car and 2) the funds for supporting mods, and 3) the time. Usually I only have had two out of the three. I have read all I can on the forums, sometimes twice, and want to thank the guys who took the time to answer questions and/or wrote build threads of their cars. Mine is in its final stage, just got the turbo mounted today.
Mod list stock 7mgte with cometic MLS head gasket and ARP bolts, China manifold, hks 45mm wastegate, eBay adapter 5 bolt to 3" vband to drift motion DP, Random tech cat, custom 3" exhaust with magnaflow, Walbro 255, 550 injectors, AEM AFR, spearco style intercooler and 2.5" pipes, K&N, greddy bov, innovate wideband, and MAFT.

 

[turbogeek87]

Almost all of my questions were answered with some research, but I still have two questions about the turbo oiling system (btw, I forgot to add that I converted the engine oil system to a temperature based system). It seems that there are differing opinions as to having a restrictor in the feed line. I have a 4 AN feed, and a 10 AN return. From my mechanic days, if I remember right, adding a restrictor would increase pressure, but would slow the flow. That doesn't sound like something that would increase the lifespan of the bearings. Am I off base here? Also, it seemed like in earlier posts, a 10AN return seemed adequate, but later posts, folks are using 12 AN or bigger. Why is this?

 

[turbogeek87]

Almost all of my questions were answered with some research, but I still have two questions about the turbo oiling system (btw, I forgot to add that I converted the engine oil system to a temperature based system). It seems that there are differing opinions as to having a restrictor in the feed line. I have a 4 AN feed, and a 10 AN return. From my mechanic days, if I remember right, adding a restrictor would increase pressure, but would slow the flow. That doesn't sound like something that would increase the lifespan of the bearings. Am I off base here? Also, it seemed like in earlier posts, a 10AN return seemed adequate, but later posts, folks are using 12 AN or bigger. Why is this?

 

[miekedmr]

restrictors reduce the pressure seen by the seals, by limiting the flow into the turbo. they are necessary, especially for ball bearing types which are supposed to have less oil than journal types.

if the turbo sees too much oil pressure from the feed, it will start blowing oil into your motor as the seals wont hold it. that's my understanding.

Your return can't really be too big. It's out of caution that they recommend larger returns as it will prevent backing up the return and increasing the oil pressure seen by the seals, causing the turbo to blow oil.