Oil restrictions / larger drains for journal bearing twin turbos

terryd5150

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Mar 4, 2017
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It's seems as if many in this thread have done an excellent job describing fluid mechanics in a static environment; however, are the majority of turbo failures occurring on the VSR balancing machine, the dyno, or while revving the hell out of the car in the driveway?

The car and, by extension, the turbocharger and its fluid contents, will move in space; the oil will be exposed to inertia - what's that impact and how is it contributing here? How will that impact be overcome?

I don't believe this discussion really presents itself as a manufacturing problem (vendor flaws); instead it appears to be design vs. physics.
 
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Bnks334

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worst thread ever...

2 of the 3 things that MMP listed are items that they should have researched BEFORE releasing a turbo kit.

Maybe they need to revise how the front turbo is clocked? Maybe they need to use a turbo with a better draining housing? Maybe they need to include a new oil return line with their kit since their turbo location causes the stock line to kink? Maybe they need to add an oil restrictor to their ball-bearing turbo setups since our cars see 80+psi of oil pressure? This wouldn't (and shouldn't) be such a guessing game if MMP had obtained the oil flow/pressure requirements from the turbo manufacturer.
 

Bnks334

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As an update, VTT will not be participating on this forum any longer, largely due to this thread. I'll be enforcing the rules as they are currently written, hopefully everyone takes this seriously. This was a mutual decision as we could not come to an agreement on how this forum should be operated. I contend that it should be operated by me, my rules are subject to change as they evolve and as I find the limits of their effectiveness, I'll adjust them.


Horrible decision... did you even go through the logic of this thread? I don't think Tony had too many sound counterarguments either... but at least he is calling MMP out for how ironic this post is since it is MMP who should already have an answer to 2 of the 3 things they posted.

"Hey guys we sold you a turbo kit and now your car smokes like crazy because we didn't do our research before selling it"

oh... "but don't worry guys we will sell you more crap at high markups to "fix" this issue that MAY NOT EVEN EXIST BECAUSE WE HAVE 0 EVIDENCE."
 

langsbr

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Apr 5, 2017
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According to Tony, they left, and weren't kicked. Chris will still respond, but they won't post "new info" here. Give it time, they'll be back after the next disagreement.
 
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MMP

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Nov 10, 2016
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thanks RB for making upgraded oil drains and giving the community an option up until now as the stock oil drains are terrible!

MMP maintains that stock oil drains are way too small to adequately drain a journal bearing turbo. A ball bearing turbos flows ALOT less oil through the bearing housing since it has a 1mm restrictor that the journal bearing dosnt and ball bearing turbos still use -10 drain lines (16mm ID). Standard design practice for turbos is a -10 return line as vertical as possible to let gravity effectively drain the oil with no line restrictions.

The stock oil drains being 9mm in the metal tubes and 13mm in the flexible sections are way too small compared to what is standard oil drain design practice and the flexible section tends to collapse and kink further upsetting things.. Remember that its flow area that matters so 9mm in area is more than 3x smaller compared to 16mm line!!! The stock oil drains can barely keep up and any little upset like a kink or partial blockage etc can casue the bearing housing to not drain and leak out the seals. I dont know why BMW did that but then again this was thier first turbo car in a long time and they got alot of things wrong such as injectors, HPFPs, plastic coolant fittings that break, plastic coolant tube over radiator that bursts, coolant pumps that fail, blower fans that catch on fire, wastegate rattle failure, oil filter housing gaskets that leak, valve cover gaskets that leak, oil pan gaskets that leak, rear main seals that leak, vanos solenoids that fail, boost solenoids that fail, coil packs that fail, chargepipes that burst, carbon build up on valves, vacuum lines that fail...etc etc.. just to name a few LOL!

So stock oil drains suck. What are we left with. Currently there is only one option on the market for upgraded lines but we think we can provide a better one and at half the cost. Out parts are already in process and will be for sale in a couple months tops.

there was some mention before that the largest the oil drain line can be is 14.5mm....this is too simplistic and not fully correct. What is more correct is the largest the oil drain fitting into the block can be is 14.5mm right at the point of connection, but as we will sho below it can then increase size in the fitting to 17mm and then the hose can be 19mm, as is the MMP design.

SO some might say..."well that wont flow anymore because your putting it through the 14.5mm bit". This is also wrong as it lacks understanding of fluid dynamics and line losses and the physics there. A 6mm section of 14.5mm diameter in the fitting + a 40mm section of 17mm diameter in the fitting + a 180mm or section of 19mm ID hose has ALOT less pressure losses than a 226mm section of straight 14.5mm. Why is that? you can lookup line loses and how to calculate them but I wont go into the physics class here, rather I will just propose a simple experiment to prove it to yourself. Take a straw and blow through it and feel how hard it is to blow rapidly through the straw (the smaller the straw the better for this simple expiration to make the point). Then cut a 1/4" long piece of the straw and blow through that. You will see it get DRAMATICALLY easier to blow through the straw. And if you could attach the 1/4" section of straw to a large 1" tube the same length as the straw you cut off, you would still see it is DRAMATICALLY easier to blow through it. This is because the loses are MUCH less in the line with the short straw because loss calculations depend on not only diameter but the length of that diameter in the section of pipe.

Based on the explanation above I can tell you that the drain fitting below will flow WAY better than anything else on the market and will be attached to a 19mm ID drain hose and will be far less cost than anything else on the market. SO if your looking for the best drains, just hold tight, they are coming and you will save a ton of money too :)

MMP return fitting crossection.JPG


Also here is a video that summarizes well some of the things I discussed in the first post.

 
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Jeffman

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Jan 7, 2017
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Nice. And the last comment in the YouTube video is really important too. I think it was already stated elsewhere on this forum (@Omar?) - since the oil simply flows under gravity back into the engine it’s important to make sure that the crankcase is vented using -AN lines through the valve cover to a catch can.
 

Rob@RBTurbo

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Dec 7, 2016
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thanks RB for making upgraded oil drains and giving the community an option up until now as the stock oil drains are terrible!

MMP maintains that stock oil drains are way too small to adequately drain a journal bearing turbo. A ball bearing turbos flows ALOT less oil through the bearing housing since it has a 1mm restrictor that the journal bearing dosnt and ball bearing turbos still use -10 drain lines (16mm ID). Standard design practice for turbos is a -10 return line as vertical as possible to let gravity effectively drain the oil with no line restrictions.

The stock oil drains being 9mm in the metal tubes and 13mm in the flexible sections are way too small compared to what is standard oil drain design practice and the flexible section tends to collapse and kink further upsetting things.. Remember that its flow area that matters so 9mm in area is more than 3x smaller compared to 16mm line!!! The stock oil drains can barely keep up and any little upset like a kink or partial blockage etc can casue the bearing housing to not drain and leak out the seals. I dont know why BMW did that but then again this was thier first turbo car in a long time and they got alot of things wrong such as injectors, HPFPs, plastic coolant fittings that break, plastic coolant tube over radiator that bursts, coolant pumps that fail, blower fans that catch on fire, wastegate rattle failure, oil filter housing gaskets that leak, valve cover gaskets that leak, oil pan gaskets that leak, rear main seals that leak, vanos solenoids that fail, boost solenoids that fail, coil packs that fail, chargepipes that burst, carbon build up on valves, vacuum lines that fail...etc etc.. just to name a few LOL!

So stock oil drains suck. What are we left with. Currently there is only one option on the market for upgraded lines but we think we can provide a better one and at half the cost. Out parts are already in process and will be for sale in a couple months tops.

there was some mention before that the largest the oil drain line can be is 14.5mm....this is too simplistic and not fully correct. What is more correct is the largest the oil drain fitting into the block can be is 14.5mm right at the point of connection, but as we will sho below it can then increase size in the fitting to 17mm and then the hose can be 19mm, as is the MMP design.

SO some might say..."well that wont flow anymore because your putting it through the 14.5mm bit". This is also wrong as it lacks understanding of fluid dynamics and line losses and the physics there. A 6mm section of 14.5mm diameter in the fitting + a 40mm section of 17mm diameter in the fitting + a 180mm or section of 19mm ID hose has ALOT less pressure losses than a 226mm section of straight 14.5mm. Why is that? you can lookup line loses and how to calculate them but I wont go into the physics class here, rather I will just propose a simple experiment to prove it to yourself. Take a straw and blow through it and feel how hard it is to blow rapidly through the straw (the smaller the straw the better for this simple expiration to make the point). Then cut a 1/4" long piece of the straw and blow through that. You will see it get DRAMATICALLY easier to blow through the straw. And if you could attach the 1/4" section of straw to a large 1" tube the same length as the straw you cut off, you would still see it is DRAMATICALLY easier to blow through it. This is because the loses are MUCH less in the line with the short straw because loss calculations depend on not only diameter but the length of that diameter in the section of pipe.

Based on the explanation above I can tell you that the drain fitting below will flow WAY better than anything else on the market and will be attached to a 19mm ID drain hose and will be far less cost than anything else on the market. SO if your looking for the best drains, just hold tight, they are coming and you will save a ton of money too :)

View attachment 10343

Also here is a video that summarizes well some of the things I discussed in the first post.


Couple bits for you:
N54 Centersection drain outlet is ~14mm
N54 Block drain inlet is ~12.5mm
RB Drains fittings are ~14.5MM and connecting hose is ~16mm
-10AN fittings are ~12.5mm and -10AN hose ~14mm
-12AN fittings are ~15.5mm and -12AN hose ~17.5mm
NOTE: There can be some minor deviation in AN sizing pending on hose end styles, manufacturers, etc.

It is worth clarifying that making the oil drain any larger than the turbo exit, is not going to amount to any "drain gains" over the 6" of straight pathway travel into its downstream 12.5mm block opening. Thus producing an "upgraded" (over the existing upgrade) "Zeppelin" shaped drain is not going to generate anything aside for an even worse fitment.

Unsolicited we were told that our RB High Flow drains made no help for a couple of these guys, so perhaps it is fair to deduce that none of the others whom also purchased the RB upgraded oil drains found a resolve either? And now of course the answer must then be that the drain needs to be an even LARGER "Zeppelin" style drain?

(EDITED PORTION OUT DUE TO VENDOR COMPLAINT)

Rob
 
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MMP

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Nov 10, 2016
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Houston, Texas
Funny I got just the opposite, unsolicited some that purchased reached out to me and said it did solve their issue and no one of my customers has reached out to me to say that it didn't work for them. However for those you say that your drain didn't work for them and the turbo shows they are in good shape, I suggest as a last resort since everything else has been addressed to look at the oil supply side as I wrote in my first post.
 

Rob@RBTurbo

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Funny I got just the opposite, unsolicited some that purchased reached out to me and said it did solve their issue and no one of my customers has reached out to me to say that it didn't work for them. However for those you say that your drain didn't work for them and the turbo shows they are in good shape, I suggest as a last resort since everything else has been addressed to look at the oil supply side as I wrote in my first post.

Thank you for sharing that you have seen some find a positive result, if you could have them email us that would be great as it would be nice to have their testimonial about the product.

Rob
 

STE92

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What about oil pressure, can that be a big factor to this problem? Had an interesting conversations with precision tech about how that oil pressure in the N54 at idle/acceleration can exceed 80-100psi. He stated way too much pressure for journal bearing turbo and it would eventually smoke without doubt.
 
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Rob@RBTurbo

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What about oil pressure? Had an interesting conversations with presicion tech about how that oil pressure in the N54 at idle/acceleration can exceed 80-100psi. He stated way too much pressure for journal bearing turbo and it would eventually smoke without doubt.

The N54 definitely can have some high oil pressure but not that high under those scenarios, there was a thread on another forum that tested it long LONG ago perhaps in about 2011?

At any rate the answers to all the N54 turbo smoking woes have been clearly identified in post #11 of this thread.

Rob
 

veer90

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What about oil pressure, can that be a big factor to this problem? Had an interesting conversations with precision tech about how that oil pressure in the N54 at idle/acceleration can exceed 80-100psi. He stated way too much pressure for journal bearing turbo and it would eventually smoke without doubt.

would be easy for someone with a top mount single to splice a gauge into their turbo feed line and find out exactly how much oil pressure.

also lol @ precision blaming high oil pressure... their turbos suck. sure they make power but I know several people who blew up their JB precision turbos within a few thousand miles.
 

fmorelli

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I will likely drop in the RB lines when I do turbos, since I'm in there. From my perspective, OE lines might be fine but why not upgrade if I'm already in there? No one seems to argue whether the RB lines are better or not - just whether they are needed or not.

Filippo
 
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Rob@RBTurbo

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I will likely drop in the RB lines when I do turbos, since I'm in there. From my perspective, OE lines might be fine but why not upgrade if I'm already in there? No one seems to argue whether the RB lines are better or not - just whether they are needed or not.

Filippo

Not required as long as the OEM's aren't buggered up. But fairly cheap insurance and definitely a better drain design. Simplified in a word: "Recommended"
 
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