3400 turbo I'm building.

[nocutt]

The GT series DEFINITELY needs an oil restrictor. My GT30R has one.

My T4 does not have an oil restrictor and it does not need one.

Tim

For sure...I know those are internally restricted and still need some more restriction to an internal pressure that should meet or not exceed ~3Xpsi...

I've heard that the emmisions tests for strictness is only second to Cali, but I have not verified that.

You just have... United states of California...It has been 5 yrs we are still trying get an EO# for a pair of freaking 3800 headers...pssh Politicians and Politics.

either case the setup looks very promising...

[Kohburn]

The GT series DEFINITELY needs an oil restrictor. My GT30R has one.

My T4 does not have an oil restrictor and it does not need one.

For PCV valves and the like, I'm now running medium pressure valves from McMaster. They actually look really good. They crack at 0.3 psi, hold 400+ psi, and are good for over 400 degrees. I'm hoping that they can help keep my crankcase under vacuum at all times.

Tim

a slight vacuum is ok - too much can cause cavitation in the oil pump..and too little fresh air cross flow can cause accelerated corrosion inside the crankcase.

the PCV system is designed to no only remove and reburn blow by gasses, but also to draw in fresh air to remove the volatal mixture from the crankcase.

my current PCV system uses a filter breather, but could just as easily be plumbed into the intake pre-turbo.. the PCV valve end is drawing from the center crank case vent line through a catch can.. this creates a fresh air flow from the valves down through the case and back up to the lifter valley keeping the valves and cams clean and cooler and the air flow actually should improve oil drain back.

[germ]

Germ I don't want to take anything from this thread,...maybe we can start a thread about all the misconceptions, myths and tradesecrets surrounding turbos...if you care :

by all means, feel free to start one up

what is this oil pressure you are talking about..(.in regards to the 3400? We might end up arguing on semantics...):

First check feed, drain and crank case to make sure they meet specifications...I think most GMV6s have about 8Xpsi of oil pressure at WOT...

thats what you said in a previous post

this is what you just said...

For sure...I know those are internally restricted and still need some more restriction to an internal pressure that should meet or not exceed ~3Xpsi...

its no different for a journal bearing.

if you go over 20psi AT THE TURBO'S oil inlet, there is a very good chance your forcing to much oil into the passages of the CHRA, thus leaking oil out of the bearings, as i previously stated.

In any event, there are several accounts of horror stories: using restrictor pills. Remember this things are spinning in some cases over 100,000RPMs...at this high RPM threholds they need all the oil they can get. If one is using the 'right feed' and the 'right drain' you CANNOT pressurize the CHRA, think about it for a second; as long as the drain is much larger than the feed it seems counter intuitive...and this is not idealism speaking... I know of several 2.8,3.4 and 3800s turbos that do not use restriction pills...
BTW I am vehemently saying every oil restrictor is a potential "bandaid", but for the most part if we are talking most stock setups...it may end up been kink lines, physical obstructions within the lines, hose sizes etc, etc...how many ppl actually diagnose the issue enough to warrant pills?

I 'mispoke'...I meant non-journals, that would be DBB,BBs by Garrett...in essence the GTs.
Nevertheless post the oil pressure at idle, hot and WOT...and what type of oil if you don't mind...

sorry for the jack Raven

not all cars need an oil restrictor. not all cars push the oil pressures we do.

at idle, the turbo does not require a lot of oil. as rpms go up, and oil pressure goes up, that supplies more oil to the faster spining shaft.


and just so you know, the CHRA is not straight through, there are oil passages that direct oil to the bearings and such, so the passages can be pressurized and thus oil is passed by the seals.


also, i am more or less speaking about the turbo that is being used in the O.P.'s setup. i have 1st hand experience with these turbo's and they do require an oil restrictor when used on our engines.


as for what you have seen with other cars not using them, i have probably seen as many with a restrictor.

so i dont know what to tell you