Oil return sitting too low - a Myth?
06-08-2006, 07:27 AM
#1
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Oil return sitting too low - a Myth?
I just thought about the whole "oil return must sit as high as possible" explanation.
I believe greddy now makes turbo kits where they plug up to where the oil plug is, which is usually at the lowest spot on the pan.
as oil is drained from the turbo, the oil in the pan would rise, since equal atmospheric pressure are applied to both the area in the pan and in the tube.
I've seen alot of threads where people had manifolds where the turbo sat "too low" and wouldn't have the proper drain.
I think lowering the return fitting on the pan would not cause any issues.
I believe greddy now makes turbo kits where they plug up to where the oil plug is, which is usually at the lowest spot on the pan.
as oil is drained from the turbo, the oil in the pan would rise, since equal atmospheric pressure are applied to both the area in the pan and in the tube.
I've seen alot of threads where people had manifolds where the turbo sat "too low" and wouldn't have the proper drain.
I think lowering the return fitting on the pan would not cause any issues.
06-08-2006, 07:28 AM
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Re: Oil return sitting too low - a Myth? (igo4bmx)
Mine was too low, and my car smoked like a freight train at idle, and eventunally ruined my turbo seals. Not a myth for me.
06-08-2006, 07:31 AM
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Re: Oil return sitting too low - a Myth? (igo4bmx)
just a thought on this, sense atmosphereic is 14.7 and your oil pressure should never be that low, wouldn't it not drain from the tube into the pan fast enough at say WOT at say 75psi oil pressure. i hate fluid dynamics so correct me if i'm wrong
06-08-2006, 07:36 AM
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Re: Oil return sitting too low - a Myth? (EJ1 wilcox)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by EJ1 wilcox »</TD></TR><TR><TD CLASS="quote">Interesting.
Do you have a link to this new Greddy kit by any chance?</TD></TR></TABLE>
wait... i may be wrong it might not be greddy.
Someone here mentioned that a large parts manufacturer made a kit for a non honda that did this.
Do you have a link to this new Greddy kit by any chance?</TD></TR></TABLE>
wait... i may be wrong it might not be greddy.
Someone here mentioned that a large parts manufacturer made a kit for a non honda that did this.
06-08-2006, 07:50 AM
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Re: Oil return sitting too low - a Myth? (igo4bmx)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by igo4bmx »</TD></TR><TR><TD CLASS="quote">
as oil is drained from the turbo, the oil in the pan would rise, since equal atmospheric pressure are applied to both the area in the pan and in the tube.</TD></TR></TABLE>
This is the way I see it. If the oil pan and oil return line are both seeing the same pressure, regardless of whether it's atmospheric pressure or not, the return line will not flow. In the case of atmospheric pressure, you have that *per square inch* across the surface of the oil in the oil pan. The same in the oil return line (if there's actually any air in there). I guess you can kinda see what I'm getting at, there's just not enough force for the return line to fight it's way into the oil pan over the 14.7lbs of pressure per square inch in the oil pan.
At WOT the pressure in the oil return line will be increased dramatically, and will flow correctly. But during low throttle and idle, you're sunk.
That's just my logic, no evidence to back it up.
as oil is drained from the turbo, the oil in the pan would rise, since equal atmospheric pressure are applied to both the area in the pan and in the tube.</TD></TR></TABLE>
This is the way I see it. If the oil pan and oil return line are both seeing the same pressure, regardless of whether it's atmospheric pressure or not, the return line will not flow. In the case of atmospheric pressure, you have that *per square inch* across the surface of the oil in the oil pan. The same in the oil return line (if there's actually any air in there). I guess you can kinda see what I'm getting at, there's just not enough force for the return line to fight it's way into the oil pan over the 14.7lbs of pressure per square inch in the oil pan.
At WOT the pressure in the oil return line will be increased dramatically, and will flow correctly. But during low throttle and idle, you're sunk.
That's just my logic, no evidence to back it up.
06-08-2006, 08:05 AM
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Re: Oil return sitting too low - a Myth? (SovXietday)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by SovXietday »</TD></TR><TR><TD CLASS="quote">This is the way I see it. If the oil pan and oil return line are both seeing the same pressure, regardless of whether it's atmospheric pressure or not, the return line will not flow. In the case of atmospheric pressure, you have that *per square inch* across the surface of the oil in the oil pan. The same in the oil return line (if there's actually any air in there). I guess you can kinda see what I'm getting at, there's just not enough force for the return line to fight it's way into the oil pan over the 14.7lbs of pressure per square inch in the oil pan.
At WOT the pressure in the oil return line will be increased dramatically, and will flow correctly. But during low throttle and idle, you're sunk.
That's just my logic, no evidence to back it up.</TD></TR></TABLE>
I understand what you are saying, but if you tried this very scenario with water in tubes, you will see the small tube and large pan will always level out to the same height.
it's some damn principle, but i don't know the name of it.
At WOT the pressure in the oil return line will be increased dramatically, and will flow correctly. But during low throttle and idle, you're sunk.
That's just my logic, no evidence to back it up.</TD></TR></TABLE>
I understand what you are saying, but if you tried this very scenario with water in tubes, you will see the small tube and large pan will always level out to the same height.
it's some damn principle, but i don't know the name of it.
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06-08-2006, 08:08 AM
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Oil isn't going to drain like water though, the oil will simply not drain fast enough to equalize with the pan and will back up into the turbo causing seal failure.
06-08-2006, 08:13 AM
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Re: (nonvtecD)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by nonvtecD »</TD></TR><TR><TD CLASS="quote">Oil isn't going to drain like water though, the oil will simply not drain fast enough to equalize with the pan and will back up into the turbo causing seal failure. </TD></TR></TABLE>
i always had the impression the amount of oil flowing from the return was not alot
i always had the impression the amount of oil flowing from the return was not alot
06-08-2006, 09:07 AM
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Re: (boost_addict)
i also think their pickup is right next to the drain bolt which could more actively suck the oil outof the drain line
06-08-2006, 10:53 AM
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for the record, he moved it up higher, no problems so far.
for the record, he moved it up higher, no problems so far.
06-08-2006, 01:39 PM
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Re: (clip the apex)
I think your diagram portrays it incorrectly.
The oil that is coming into the turbo is pressurized. The return line uses gravity to drain. If you put the drain at the very bottom of the pan, the oil has to work against the pressure inside the block against the oil in the pan and eventually will back up into the turbo causing seals to fail.
In the second diagram, the oil flows without any restriction into the pan so the only thing that can ruin your seals is too much oil pressure coming into the turbo.
That is a crappy explanation.. I hope you get the point.
Microsoft Paint FtW!
The oil that is coming into the turbo is pressurized. The return line uses gravity to drain. If you put the drain at the very bottom of the pan, the oil has to work against the pressure inside the block against the oil in the pan and eventually will back up into the turbo causing seals to fail.
In the second diagram, the oil flows without any restriction into the pan so the only thing that can ruin your seals is too much oil pressure coming into the turbo.
That is a crappy explanation.. I hope you get the point.
Microsoft Paint FtW!
06-08-2006, 04:06 PM
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Crank case pressure.....there will be more pressure then atmospheric pressure in the oilpan, unless you have a very good pcv system, or a pump for the pcv system.
06-08-2006, 04:24 PM
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Re: (Semnos)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Semnos »</TD></TR><TR><TD CLASS="quote">Crank case pressure.....there will be more pressure then atmospheric pressure in the oilpan, unless you have a very good pcv system, or a pump for the pcv system.</TD></TR></TABLE>
I wonder how much pressure that really is? I have seen quite a few posts on how people correct smoking problems by moving the return line higher. I guess there is quite a bit of pressure in the crank case then.
The oil return line should be big enough were no matter the inflow of oil to the turbo, the return line should be emptying fast enough. the diagram from huepowered should have a little air pocket between the turbo and return line
I wonder how much pressure that really is? I have seen quite a few posts on how people correct smoking problems by moving the return line higher. I guess there is quite a bit of pressure in the crank case then.
The oil return line should be big enough were no matter the inflow of oil to the turbo, the return line should be emptying fast enough. the diagram from huepowered should have a little air pocket between the turbo and return line
06-08-2006, 05:36 PM
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Re: (adseguy)
Mine use to be in the oil. What would happen is it would start out fine, draining good, and then after a bit it would start to back up. I put a clear line on my return so i could figure it out. If i pulled my dipstick out, it would drop some for a time. Only thing i could come up with was, that your turbo seals up via air basicaly, or well my turbo does. I feel it was creating a vacum and sucking the oil in, and up the line. I don't know, i created a pcv system, see the latest thread if you need to, but it goes to pre turbo, thus making a vacum from the crankcase, and valve cover. Helped some, but not enough. So, i made a new hole up above the oil, and no more issues 
My line is really tight too.... so, say what you want, and it may work, but screw that It may have hurt me too, that i run an aftermarket pan, with trap doors, not sure how much that would hurt.....
My line is really tight too.... so, say what you want, and it may work, but screw that It may have hurt me too, that i run an aftermarket pan, with trap doors, not sure how much that would hurt.....
06-08-2006, 05:47 PM
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Re: (shortyz21)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by shortyz21 »</TD></TR><TR><TD CLASS="quote">i heard that when oil comes outta the turbo its quite "frothy"...
</TD></TR></TABLE>
Heard that too, never seen it though I run a 3an line also. Mine flows out.
</TD></TR></TABLE>
Heard that too, never seen it though
I run a 3an line also. Mine flows out.
06-08-2006, 05:53 PM
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Re: Oil return sitting too low - a Myth? (igo4bmx)
It doesnt take much to blow the oil past the seals in a turbo, thats a great way to mess it up in a hurry. You have pressures that are constantly tryin to vent from the crankcase so this theory wouldnt work.
Also with out a way to vent the return line, it will cause it to back up because of too much volume being fed by the feed. It'll almost airlock the return slowing the drain and causeing a back up of the oiling system. This will cause an increase in pressure at the seals.
an oil inlet restrictor is recommended if you have oil pressure over about 60 psig. The oil outlet should be plumbed to the oil pan above the oil level (for wet sump systems). Since the oil drain is gravity fed, it is important that the oil outlet points downward, and that the drain tube does not become horizontal or go “uphill” at any point. -turbobygarrett.com
Also with out a way to vent the return line, it will cause it to back up because of too much volume being fed by the feed. It'll almost airlock the return slowing the drain and causeing a back up of the oiling system. This will cause an increase in pressure at the seals.
an oil inlet restrictor is recommended if you have oil pressure over about 60 psig. The oil outlet should be plumbed to the oil pan above the oil level (for wet sump systems). Since the oil drain is gravity fed, it is important that the oil outlet points downward, and that the drain tube does not become horizontal or go “uphill” at any point. -turbobygarrett.com
06-08-2006, 07:06 PM
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Re: Oil return sitting too low - a Myth? (igo4bmx)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by igo4bmx »</TD></TR><TR><TD CLASS="quote">I understand what you are saying, but if you tried this very scenario with water in tubes, you will see the small tube and large pan will always level out to the same height.
it's some damn principle, but i don't know the name of it.</TD></TR></TABLE>
That doesn't mean it's flowing though.
it's some damn principle, but i don't know the name of it.</TD></TR></TABLE>
That doesn't mean it's flowing though.
06-08-2006, 07:15 PM
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Re: Oil return sitting too low - a Myth? (SovXietday)
Take a 1 inch pipe (clear if possible)
Take a water hose w/ some pressure behind it.
Take a kid's pool
Take the 1 inch pipe put it in the pool
Take the Hose and spray it in the 1 inch pipe (make sure the pipe is sealed to the hose)
You’ll see that even "water" will start to build "slightly" from getting air locked in the tube, slowing the return flow of water.
As viscosity goes up things slow up and the return hose will get air locked much more dramatically then a water example would.
Take a water hose w/ some pressure behind it.
Take a kid's pool
Take the 1 inch pipe put it in the pool
Take the Hose and spray it in the 1 inch pipe (make sure the pipe is sealed to the hose)
You’ll see that even "water" will start to build "slightly" from getting air locked in the tube, slowing the return flow of water.
As viscosity goes up things slow up and the return hose will get air locked much more dramatically then a water example would.
06-08-2006, 09:23 PM
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Re: Oil return sitting too low - a Myth? (JDMs1eeper)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by adseguy »</TD></TR><TR><TD CLASS="quote">
I wonder how much pressure that really is? I have seen quite a few posts on how people correct smoking problems by moving the return line higher. I guess there is quite a bit of pressure in the crank case then.
The oil return line should be big enough were no matter the inflow of oil to the turbo, the return line should be emptying fast enough. the diagram from huepowered should have a little air pocket between the turbo and return line</TD></TR></TABLE>
yeah, the second picture should really look like a half filled tube draining off into the open oil pan..
I wonder how much pressure that really is? I have seen quite a few posts on how people correct smoking problems by moving the return line higher. I guess there is quite a bit of pressure in the crank case then.
The oil return line should be big enough were no matter the inflow of oil to the turbo, the return line should be emptying fast enough. the diagram from huepowered should have a little air pocket between the turbo and return line</TD></TR></TABLE>
yeah, the second picture should really look like a half filled tube draining off into the open oil pan..