EFR turbos and oil drains

[Gripless]

So EFR turbos are sensitive to pressure in the drain system. Eg if you have positive crank case pressure they will push oil past the seals.

14-60psi operating pressure

20degrees rotation from vertical 

 

You really need 12mm or larger drain and a larger diameter hose/pipe to the sump.

Do NOT use banjo or threaded fittings for oil drain.

 

-10an or smaller is suited to scavenger pump oil return like Porsche.

3/4 hose/pipe recommended 

a small oil tank under the turbo can help with frothing oil and cleaner return. Thinking of billet fuel filter with filter cove removed so has 50mm diameter chamber to allow foam to settle.

 

More info

https://www.miataturbo.net/diy-turbo-discussion-14/psa-efr-turbo-oil-drain-information-read-before-designing-your-oil-drain-93944/

https://turbosource.com/blogs/news/borgwarner-efr-technical-installation-guide

 

 

This may apply to newer garrret turbos as well.

 

 

fittings

https://www.aliexpress.com/item/32404284074.html

https://www.aliexpress.com/item/33052615896.html
 

 

Thanks to @Andy_Mac for putting me onto all this.

 

Edited November 22, 2023 by Gripless

[Gripless]

Skid factory video

 

https://www.youtube.com/watch?v=zJchCTVvjgQ

 

https://www.youtube.com/watch?v=cfXxs7jxH88?t=354

 

 

Edited November 24, 2023 by Gripless

[Andy_Mac]

Interesting watch.

I've been wondering if a big ass 3/4 drain off the turbo with a tee going back to an AOS then to intake would help to pull some of the oil vapour out early on or whether that suction would hold things up at the bottom block drain point. 

[Gripless]

I think AOS designs are mostly pretty or clones of someone’s else idea more than functional.

Seems far better to replace the head baffle system with a better one than run a separate AOS.

 

line to intake may need the low mount sump and breather otherwise the intake vacuum would be pulling oil through the turbo.

[Andy_Mac]

10 minutes ago, Gripless said:

I think AOS designs are mostly pretty or clones of someone’s else idea more than functional.

Seems far better to replace the head baffle system with a better one than run a separate AOS.

 

line to intake may need the low mount sump and breather otherwise the intake vacuum would be pulling oil through the turbo.

 

I was thinking aos solely for the idea that I wouldn't want that vapour entering the turbo as it was. But it would probably be a bit too oily to just vent or add to a catch can

 

How is that any different to a dry sump with a dedicated turbo scavenge or just a dry sump in general since it’s actively pulling the crankcase into an attempted slight vacuum.

[Gripless]

Turbo drains cut away, with oil issue causes

https://www.youtube.com/watch?v=hGSoe-sZcXk

Oil issues

jumps to timestamp for Crankcase vent 
https://youtu.be/X9pzZCFXrV4?t=226

 

even CV hose length causing issues.

https://www.youtube.com/watch?v=KopDR9A9uas

 

 

[Andy_Mac]

1 hour ago, Gripless said:

Turbo drains cut away, with oil issue causes

https://www.youtube.com/watch?v=hGSoe-sZcXk

Oil issues

jumps to timestamp for Crankcase vent 
https://youtu.be/X9pzZCFXrV4?t=226

 

even CV hose length causing issues.

https://www.youtube.com/watch?v=KopDR9A9uas

 

 

 

Only watched the first one but definitely makes me want to commit to making a custom 3/4 drain setup. Long idling is an interesting point too. I let mine idle for a considerable time so could be a factor in all of this also. Though mine is worst during decel where the raves are still up there a bit so shouldn't be slow enough to not be slingin’

 

I was thinking about this the other day and whether going to an e-gate and having it fully open at idle would help at all or make things worse. It'd either slow the turbo down so much it barely spins and possibly reduce the need for the slinger at all or just make it worse since it won't be doing anything

[Gripless]

Turbo oil seals aren’t what keeps the oil in.

It’s a spiral cut in the washer or shaft are designed to fling oil back towards the middle to controls oil leaks. This was a part of Haley Davidson early bikes to solve oil issues. Not sure they invented it but they made it popular.

The slower the shaft speed the worse the oil leak will be as it can’t fling the oil away from the seal. Think of it like a pump, slower it runs the less oil it can move away from the seals.

1 hour ago, Andy_Mac said:

 

Only watched the first one but definitely makes me want to commit to making a custom 3/4 drain setup. Long idling is an interesting point too. 

3/4 is only a help if the crankcase pressure is good. They other 2 videos cover that as well.

last one even adding the catch an to a system can raise crankcase pressure to the point it pressurises the drain no matter the size.

 

 

[Gripless]

Radium

pretty much comes down to don’t combine PCV and head vents. So all those running single catchcans for all things will have issues.

 

https://www.radiumauto.com/Blog/Post/New-Product-Release-Subaru-AOS-and-Oil-Catch-Cans-103

 

https://www.radiumauto.com/Blog/Post/Catch-Cans-101-102
 

[boon]

My EFR came with a really small AN fitting threaded into the drain. But then it was also #racecar so maybe doing some bizarre stuff us road car plebs don't have access to. I've gone for whatever the Subaru factory oil return is - 5/8"?

[Gripless]

Mine is stock drain sized from the outside, but it’s the crankcase and head vents to the radium AOS that seems to be the cause.

I may remove the drain and check the gasket isn’t blocking things at some point.

 

Most likely I’m going to find the AOS breather and plumb it back to the intake for some vacuum.

[Andy_Mac]

3 hours ago, boon said:

My EFR came with a really small AN fitting threaded into the drain. But then it was also #racecar so maybe doing some bizarre stuff us road car plebs don't have access to. I've gone for whatever the Subaru factory oil return is - 5/8"?

 

Possibly also had a dry sump on the engine since racecar so that removes the size issue. 

And yea standard is 5/8

 

@Gripless surely at some point though it's spinning slow enough to not get all frothy and whatnot and kinda drip down rather than flicking all over the place

[Gripless]

 

The drain pressure will build up until the area under the bearings and the tiny gap the oil goes through is all under pressure from crankcase. Then any vacuum in the intake or low exhaust pressure will have more effect than gravity.