Das Beast: My E30 track / street build

[dvallis]

Update: Tuning prep delay. Got taken down by pneumonia but on the mend. Ungh.

[citizen_insane]

I'd seriously reconsider that 90° bend you have in your oil drain line. It doesn't look like you need it for packaging, so I suggest replacing it with a straight fitting. Adding a restriction like that can cause oil to build up in the core and get pulled through the turbo seals.

[nina.bird007]

What a beauty! And I dream of a BMW X5 :)

[Fraser]

Where did you get that oil drain fitting? I've been looking for something like that...

[Digitalwave]

I'd seriously reconsider that 90° bend you have in your oil drain line. It doesn't look like you need it for packaging, so I suggest replacing it with a straight fitting. Adding a restriction like that can cause oil to build up in the core and get pulled through the turbo seals.

Why would a bend that is the same size as the main line create a restriction?

[ForcedFirebird]

Why would a bend that is the same size as the main line create a restriction?

I have never had an issue with it, been using 90s in oil drains for years (albeit, it's usually at the bottom, not top).

[citizen_insane]

Why would a bend that is the same size as the main line create a restriction?

Any bend in a tube creates a restriction to flow. Having this restriction this close to the turbo increases the chance that you'll have oil back up, flood the oil core, and get oil pulled past the piston rings into either the compressor or turbine stage.

I have never had an issue with it, been using 90s in oil drains for years (albeit, it's usually at the bottom, not top).

The bottom is better but still not ideal. It's better because you have the entire volume of the hose to fill up before you flood the core, which might be enough to keep the issues at bay, flooding is generally a transient issue, not a steady state one.

Ideally you'd have a straight shot, to the pan, but when not possible, you want the most gentile bend possible.

[ForcedFirebird]

The bottom is better but still not ideal. It's better because you have the entire volume of the hose to fill up before you flood the core, which might be enough to keep the issues at bay, flooding is generally a transient issue, not a steady state one.

Ideally you'd have a straight shot, to the pan, but when not possible, you want the most gentile bend possible.

If you have oil backing up a 10 or 12 -an line with 1 or even 2 90° bends, you have other issues. There's not enough restriction in a 10/12 for a 3 or 4 -an fitting to supply enough oil (even more so if a restrictor is in place) to offset the flow. Saying a 90 will back up flow is no different than the internet assumption that the oil drain must dump above the oil level in the pan - which is not true. Generally the passenger side of the oil pan in BMW inline engines is submerged, and in a pinch, I have even used the oil drain plug to dump the drain - and with the 14mm fitting, the oil still didn't back up. Fluids naturally seek level. The turbo bearings are only going to flow so much (as they are a restriction in themselves).



Back when e30tech was operational, there was a fellow that was having oil burning issues in his turbo. Putting a clear hose on the drain, he was able to rule out the oil backing up. It's an awesome visual reference...

https://www.youtube.com/watch?v=Gkaa7gV35lI

This is based on experience, I have built many turbo kits where space was limited and used a bend directly off the turbo without issue. One of my GM buddies even had a 90 straight off the turbo which was mounted high enough to dump laterally into the valve cover. Turbo ran for many years this way.

[zaq123]

Das Beast: My E30 track / street build

If you have oil backing up a 10 or 12 -an line with 1 or even 2 90° bends, you have other issues. There's not enough restriction in a 10/12 for a 3 or 4 -an fitting to supply enough oil (even more so if a restrictor is in place) to offset the flow. Saying a 90 will back up flow is no different than the internet assumption that the oil drain must dump above the oil level in the pan - which is not true. Generally the passenger side of the oil pan in BMW inline engines is submerged, and in a pinch, I have even used the oil drain plug to dump the drain - and with the 14mm fitting, the oil still didn't back up. Fluids naturally seek level. The turbo bearings are only going to flow so much (as they are a restriction in themselves).



Back when e30tech was operational, there was a fellow that was having oil burning issues in his turbo. Putting a clear hose on the drain, he was able to rule out the oil backing up. It's an awesome visual reference...

https://www.youtube.com/watch?v=Gkaa7gV35lI

This is based on experience, I have built many turbo kits where space was limited and used a bend directly off the turbo without issue. One of my GM buddies even had a 90 straight off the turbo which was mounted high enough to dump laterally into the valve cover. Turbo ran for many years this way.

Not the turbo expert here by any means. Every turbo manual out there calls for straight as possible run above the oil line.

It’s a gravity run. Just because you don’t see full hose doesn’t mean there is no back pressure. Run that line in the video above the oil level and that hose will drain faster.

Everyone who has done a beer funnel should know it by experience


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[ForcedFirebird]

Not the turbo expert here by any means. Every turbo manual out there calls for straight as possible run above the oil line.

It’s a gravity run. Just because you don’t see full hose doesn’t mean there is no back pressure. Run that line in the video above the oil level and that hose will drain faster.

Everyone who has done a beer funnel should know it by experience


Sent from my iPhone using Tapatalk

Straight as possible, sure, but packaging can cause issues with it. If you need to add a bend, it's not overly difficult to go with a larger diameter drain. Also, check the quality of the fittings, I have seen the cheap fittings that are claimed to be -10 and are closer to -8 so they are easier to manufacture.



The statement about the drain being above the oil level is from when I was turbo-ing GM cars many years ago. Everyone on the internet claimed you can't run a drain below the fill line. When I started working on BMW's, I shortly realized you really can't get the drain above the oil level without either running the drain all the way around the engine, or put a fitting in the cast iron block - the passenger side gasket is always submerged. Not sure it will drain faster, you just wouldn't see it backing up in the hose if the end was open to atmosphere (there's still the same amount of oil leaving the turbo).



I am also no expert, either, but do get paid to do this crap. :/

[zaq123]

http://www.turboneticsinc.com/performance/sites/default/files/60197_revA_1.pdf

https://www.precisionturbo.net/tech/PDFs/PTE-turbocharger-install-recommendations.pdf

[ForcedFirebird]

http://www.turboneticsinc.com/perfor...197_revA_1.pdf

https://www.precisionturbo.net/tech/...mendations.pdf

Rather then base an opinion on vague installation instructions, let's look at fluid dynamics and see the science behind it (because science!):

https://neutrium.net/fluid_flow/calculation-of-flow-through-nozzles-and-orifices/

http://www.thermopedia.com/content/577/

http://instrumentationandcontrol.net/Orifice-Calculator-Sizing-Liquid-Flow-Metric.html

https://wiki.anton-paar.com/en/engine-oil/

Plug the numbers in the formulas: 5mm feed line, 1mm vertical orifice (journal bearing) dumping into a 15mm drain, 60w oil, ~3gpm, take that number and calculate the restriction of a 90° bend (the calculated pressure is a small number).


Then use this formula to calculate flow loss.

http://instrumentationandcontrol.net/Orifice-Calculator-Sizing-Liquid-Flow-Metric.html

In my experience, three things cause oil drains to back up (providing it's gravity fed, not a low mount turbo with a scavenge pump) :


1. Drain has an upward bend before the end of the drain causing a fluid trap

2. Excessive crank case pressure causing a high pressure/drain ratio.

3. Too large feed line to drain line ratio.

My opinion stands: Davillis' turbo will drain fine.

[parkerbink]

lol

[e30RS]

Hey man hope you are feeling better! This has been an awesome project. Great nickname.

[dvallis]

I'm back! Pneumonia sucks LoL.

And yes .... SCIENCE, BITCHES. My turbo oil feed is not a bloody free flowing garden hose. Its oil at 60 psi. I could tie balloon animals in the hose and it will still feed oil. Ever see those curly hoses on semi trucks? They are for air brakes. Air or any fluid under pressure cares little about the shape of a hose.

Drain is fine. Its 10AN. May as well be a kitchen drain compared to the feed.

More later ....