2.5GT Turbo Oil Supply Banjo Bolt Filter Removal

[JoeFromPA]

I tried to get some momentum on this, or at least some knowledgable input, but FP (forced performance) sells Banjo Bolts with (IIRC) no screen and 3x the size opening for oil passage, as well as a turbo oil supply line that is also 3x the stock opening size for increased oil flow. It's a necessary part when upgrading to a variety of their turbos.

 

They are about $20, and my thought is to replace both the stock units with those parts, regardless of what my future turbo plans are.

 

I haven't seen anyone give this a thumbs up or thumbs down as an idea; if the theory is that the stock restrictive banjo bolt and oil supply line are to blame for a lack of lubrication and early turbo failure, than that $20 seems like a solid way to prevent that turbo failure...especially since they are designed for use in this car with turbos requiring greater oil flow.

 

Thoughts?

 

P.s. I can't believe Rao started an oil thread. Boo!

[Shik]

Joe,

 

You would have to see if you would even benefit from the aftermarket bolts.

 

It is my understanding that the screen in the banjo bolt('05 only?) is the sole culprit to failed turbos, and not even the screen, but a clogged screen. The lines will only allow "X" amount of oil to the turbo anyway, so simply going to a bolt that allows more oil will only be a benefit if the stock bolt doesn't flow 100% of the oil volume that the stock lines provide.

 

If the stock lines can provide more oil AND the stock turbo itself could allow more oil inside, then an aftermarket bolt would be an advantage. But, if the stock lines, stock bolt, and stock turbo are all matched fairly well in terms of how much oil is provided/needed, there would be no advantage to aftermarket bolts.

 

Even going to an aftermarket line and bolts won't do much if the stock turbo itself is getting the volume of oil that is required for it to be lubricated properly with the stock set up.

 

FP does make a point that their(and many larger aftermarket) turbos DO require more oil then the stock one, so upgraded bolts/line is required. But for the stock turbo...who actually knows if it would be of any benefit.

 

That being said, my choice would be stock bolt with no screen. I am still baffled as to why they put a screen in in the first place, as Subaru has always had reliable stock turbo performance. Why mess with something that works? Unless the newer turbos are THAT much more finicky when it comes to absolutely clean oil. Hell, there are some 91-94 Legacy turbos running around with over 200k still with the stock turbo working fine(albeit not modded, but still).

 

I don't think upgrading all the stuff on a stock turbo would do anything negative(turbo experts could correct me if I'm wrong), but it will probably not give you(or your stock turbo) and benefits either.

 

-Matt

[JoeFromPA]

Shik - Thanks for the feedback. I haven't read any 07/08 owners who have inspected their banjo bolts, but I would feel better if they did and there was no screen.

 

One of the things this does for me though is emphasize the need to use a stock-or-better air filter, and a good quality oil filter. I've been using an AVO air filter and while the extra turbo noise is nice, I'd rather have confidence that my intake is cleaning the air properly and not exacerbating engine wear.

 

I do not think extra oil flow to the turbo would hurt, but I'm no lubrication engineer. The only thing important to me is maintaining an appropriate level of lubrication on the turbo/turbo bearings.

 

Joe

[morbius]

Shik,

 

I spoke with a Subaru mechanic in New Jersey about the banjo bolt. If you want to take his explaination for the screen he said that the size of the oil outlet in the turbo is small to keep the oil pressure up on the turbo bearing. The screen is in place to keep junk out of the bearing and to keep that outlet hole from clogging.

 

I'm not an auto mechanic or a mechanical engineer. Seems to me if it was that critical you would engineer it to be an easily accessible and maintainable part.

[mccorry]

Actually... to be specific... the "restriction" in the line is at the turbocharger bearings. Assuming that the bearings are in good shape, then only so much oil will pass between the stationary bearings and the shaft....

 

The oil is at low pressure and just drains out after passing through the bearing clearances.

[JoeFromPA]

Yeah....putting a screen in place prior to a set of bearings doesn't make much sense to keep pressure up ON the bearings.

[mccorry]

It's more to keep crap OUT OF the bearings. That's the point.

 

The issue here is not the screen.

 

The issue... and ROOT CAUSE ... of these failures is DIRTY OIL.

[JoeFromPA]

Any evidence of that? I mean, if the issue is dirty oil you are saying the turbos are failing because the oil isn't lubricating them properly or is causing them to excessively wear and fail early. If the issue is a clogged banjo bolt filter screen then it's a design flaw since the filter is not included in regular maintenance.

[sleeper8406]

vicious cycle

[Shik]

It's more to keep crap OUT OF the bearings. That's the point.

 

The issue here is not the screen.

 

The issue... and ROOT CAUSE ... of these failures is DIRTY OIL.

 

Agreed somewhat.

 

However, I hear lots of guys say they'd rather keep the screen and just keep cleaning it(or at least checking it to see if it needs to be cleaned) because they would rather that sludge build up on the screen then go through the turbo.

 

The sludge on the screen builds up over time. It's not like that amount of sludge on the screen is going to continue to go through the turbo all at once. A tiny minute fraction of that is what goes through the oiling system and through the turbo. An amount that I would bet will likely not do anything to harm the turbo over time. It hasn't to any of my other Subaru turbos in the past. And as I mentioned before, unless the tolerances on the LGT turbo are sooooo much tighter then any other turbocharger previous to this, that filter only worries me, not gives me peace of mind.

 

But yes, in the end, clean oil is a must. Still, if the screen is in there you will always have to check it because you really have no idea just how "clean" your oil. Like I said, to me, that's a pain.

[mccorry]

The screen should never see any particulates unless the main oil filter is bypassed.

If the oil pressure / back pressure on the main filter gets too high.. then the oil will bypass the oil filter and head to the engine.

 

That is the only way that you can get solids (particulates) to the screen.

 

It's a simple flow path....

 

Oil pan >> Oil pump screen >> Oil pump >> Main oil galley(s) >> Distribution to the crank, heads, turbo, etc.

[oar]

Great thread...I might have to look into doing this soon

[2006Specb122]

MCCORRY,

 

So you are saying this BANJO bolt screen is NOT the problem with all these 70 stock turbos blowing?

 

We don't have to worry about the banjo?

 

 

Has SOA communicated with ANYONE that had a blown turbo blamed on the BANJO?

 

 

 

I'm also wondering the same thing about the pick up tube.

Has SOA stepped up to address either of these issues that are so critical to the engine?

[mccorry]

Yes... that is my opinion.

I've not removed mine.

[Shik]

The screen should never see any particulates unless the main oil filter is bypassed.

If the oil pressure / back pressure on the main filter gets too high.. then the oil will bypass the oil filter and head to the engine.

 

That is the only way that you can get solids (particulates) to the screen.

 

It's a simple flow path....

 

Oil pan >> Oil pump screen >> Oil pump >> Main oil galley(s) >> Distribution to the crank, heads, turbo, etc.

 

Mccory, again, I am no expert, but no oil filter captures 100 percent of all particles. Most filters are designed to trap particles around 20 microns or larger. What happens when 2 or 3 or 4 microns continue to get built up on a mesh screen in a banjo bolt over a few thousands miles?

 

Now, just as you said, this is where clean oil and a new filter come into play. Chances are if you change it every 3000 miles, the 2 or 3 or 4 microns I mentioned will not build up enough to do anything. Change the oil and filter and clean the banjo bolt screen and you are in business for another 3000 miles. However, continue to stretch your oil changes and not clean the bolt, and those tiny particles will eventually build up on that screen. Those who change their oil regularly and use a decent filter may never have enough junk build up on the screen to worry about it. But, continue to stretch the dirty oil and keep letting tiny particles build up and you will have something to worry about.

 

Now, how could a mesh screen trap pieces that the oil filter can't. I'm going to say most of the time it can't. But, it just takes one too many particles(dirtier oil) to get stuck on the wire mesh. Then another particle sticks to that one, and then another and another. Pretty soon, one of the minute holes in the mesh screen begins to get blocked. Over 10s of thousands of miles of not cleaning the screen, you may have a problem.

 

Besides that, the by-pass valve on filters will open when oil psi gets too high, you are right. They open when the oil filter gets totally blocked(which takes a lot to totally block a filter), OR when the engine is cold and the oil is not at it's operating temp yet, or at least not a temp to have the oil thinned out enough to bring the oil psi to normal operating psi. So chances are, everyone who is on this board with a Legacy GT has had unfiltered oil go through their engine. And considering many of us are just coming out of a cold winter, numerous times a day.

 

[breath]

 

All that being said, IMHO, there is the possibility of the banjo bolt screen doing more harm then good. If cleaned periodically and oil and filter changed often, I would guess the likelihood is very very minimal, but still. I'm not going to continue to take the banjo bolt off to clean it only because in my experience I don't think the turbocharger will suffer by not having it there if oil and filter changes are done properly.

 

Again, only my opinion, and I'm sure some others feel strongly the other way and they'll keep the filter in. In the end, it's what you decide. Honestly, either way I think your turbo will be OK. Dirty oil and not cleaning the banjo bolt...maybe not so much;)

 

I'm also wondering the same thing about the pick up tube.

Has SOA stepped up to address either of these issues that are so critical to the engine?

 

Not sure, but my local dealer said to do the pick-up is only 2.2 hours. So for the new pick up( I like innovative tuning's pick-up) and for the dealer to install it, that's peace of mind for under $300 and me not getting dirty

 

-Matt

[mccorry]

Mccory, again, I am no expert, but no oil filter captures 100 percent of all particles. Most filters are designed to trap particles around 20 microns or larger. What happens when 2 or 3 or 4 microns continue to get built up on a mesh screen in a banjo bolt over a few thousands miles?

 

Now, just as you said, this is where clean oil and a new filter come into play. Chances are if you change it every 3000 miles, the 2 or 3 or 4 microns I mentioned will not build up enough to do anything. Change the oil and filter and clean the banjo bolt screen and you are in business for another 3000 miles. However, continue to stretch your oil changes and not clean the bolt, and those tiny particles will eventually build up on that screen. Those who change their oil regularly and use a decent filter may never have enough junk build up on the screen to worry about it. But, continue to stretch the dirty oil and keep letting tiny particles build up and you will have something to worry about.

 

Now, how could a mesh screen trap pieces that the oil filter can't. I'm going to say most of the time it can't. But, it just takes one too many particles(dirtier oil) to get stuck on the wire mesh. Then another particle sticks to that one, and then another and another. Pretty soon, one of the minute holes in the mesh screen begins to get blocked. Over 10s of thousands of miles of not cleaning the screen, you may have a problem.

 

Besides that, the by-pass valve on filters will open when oil psi gets too high, you are right. They open when the oil filter gets totally blocked(which takes a lot to totally block a filter), OR when the engine is cold and the oil is not at it's operating temp yet, or at least not a temp to have the oil thinned out enough to bring the oil psi to normal operating psi. So chances are, everyone who is on this board with a Legacy GT has had unfiltered oil go through their engine. And considering many of us are just coming out of a cold winter, numerous times a day.

 

 

If the 2-3 micron particles pass through the oil filter... WHY on earth would they get stuck on a 400 mesh screen?

A bigger hole isn't going to clog faster than a smaller hole...

 

And as you stretch the OCI, the filter actually gets MORE efficient in filtration ..... right until it starts to plug and begins to bypass.

 

 

All that being said, IMHO, there is the possibility of the banjo bolt screen doing more harm then good. If cleaned periodically and oil and filter changed often, I would guess the likelihood is very very minimal, but still. I'm not going to continue to take the banjo bolt off to clean it only because in my experience I don't think the turbocharger will suffer by not having it there if oil and filter changes are done properly.

 

Again, only my opinion, and I'm sure some others feel strongly the other way and they'll keep the filter in. In the end, it's what you decide. Honestly, either way I think your turbo will be OK. Diry oil and not cleaning the banjo bolt...maybe not;)

 

-Matt

 

If you'd feel better, Matt... then remove the screen. No problem.

 

My only reason for getting involved is that I don't feel that this is a design fault of Subaru. If I was designing this system... I'd put a screen in there... albeit in an easier place to get to for inspection.

[Shik]

Mccory said:

If the 2-3 micron particles pass through the oil filter... WHY on earth would they get stuck on a 400 mesh screen?

A bigger hole isn't going to clog faster than a smaller hole...

 

Shik previously said:

Now, how could a mesh screen trap pieces that the oil filter can't. I'm going to say most of the time it can't. But, it just takes one too many particles(dirtier oil) to get stuck on the wire mesh. Then another particle sticks to that one, and then another and another. Pretty soon, one of the minute holes in the mesh screen begins to get blocked. Over 10s of thousands of miles of not cleaning the screen, you may have a problem

 

My only reason for getting involved is that I don't feel that this is a design fault of Subaru. If I was designing this system... I'd put a screen in there... albeit in an easier place to get to for inspection

 

That brings us to another question, at least for me. Why did Subaru even put it in there when they haven't on any of the other turbocharged models(that I know of) since the 80's?

 

My guess, and this is only a guess, but maybe a handful of turbochargers died prematurely, for whatever reason . Subaru warranty/bean counters went to the engineers and said this cannot be. Maybe told IHI if it keeps happening, they'll have to source other turbos, who knows. They came up with the screen as a fix, underestimating the amount of junk it would actually catch. Subaru can't say much because they wanted the fix in the first place so they change the OCI miles and stress the importance of clean oil in turbochaged models to cover themselves because they , along with many of us, figured out what was causing the problem.

 

What I don't think happened is that Subaru had a ton of pre-05 turbochager failures. They did studies and found that it was tiny particles killing all of these pre-2005 turbochargers and decided on a screen in the banjo bolt to trap these killer particles, knowing that the screen could eventually become clogged and kill the turbochager anyway, but overlooked that part in the owners manual.

 

Who knows.

 

-Matt

[2006Specb122]

SHIK,

 

If all of what you are saying is TRUE... and it makes sense...and is a good GUESS as you put it.... then why doesn't subaru just put out a new tech bulletin stating that they missed a critical part of maint. and tell people officially to change, replace, or clean the banjo filter???

 

With all the failure (over 70) it is still a small percentage of total cars.

BUT, I think there has to be SOMEONE who has taken it up with Subaru and received some sort of email response.

 

Anyone?

[Shik]

Good question. Someone with more warranty experience may be able to answer better, but I think what you said probably sums it up, there aren't enough of them to do it anything. Again, not sure how that works when a problem is widespread enough that the company HAS to do something or when it is just a common problem that is only thought of as a typical premature failure.

 

I know my dealer has not had any failed turbos due to the banjo bolt(2 I think due to the oil supply line breaking though on 07's maybe), and no oil pick-up problems. And they do quite a bit of service work.

 

Then, again, not sure how this works, but if a recall was issued or even a SB, now it is official that there is/was a problem so everyone that paid out of their pocket for repairs if it was not under warranty will be expecting money back from SOA, so no doubt it would turn into a rather large expense.

 

Maybe Subaru feels most ARE still under warranty, so just fix the few that do fail and call it a day. I'm sure someone can dispute this, a failed turbo isn't really a "safety" hazard(unless you break down in the middle of a rough neighborhood ) , so they just let it go.

 

If the turbo failed a spewed oil all over the downpipe or something of that nature, it would have been taken care of long ago IMHO.

 

Sucks for us, but what can you do.

[MikeAldea]

SHIK,

 

If all of what you are saying is TRUE... and it makes sense...and is a good GUESS as you put it.... then why doesn't subaru just put out a new tech bulletin stating that they missed a critical part of maint. and tell people officially to change, replace, or clean the banjo filter???

 

With all the failure (over 70) it is still a small percentage of total cars.

BUT, I think there has to be SOMEONE who has taken it up with Subaru and received some sort of email response.

 

Anyone?

 

Well Subaru Tech Bulletin 23-103-07 issued on 10/19/07, which is for informational purposes only, states:

In any case, it is recommended that the engine oil and filter be changed every 3,750 miles (6,000 km) or 3-3/4 months.

 

In addition, the mesh screen which is located inside the banjo bolt that secures the turbocharger oil supply pipe to the back of the right side cylinder head should be checked to make sure it is not clogged or restricted especially if the condition of the oil is questionable or as to when the last oil change was performed. If clogged or restricted, it will reduce or cut off the oil supply to the turbo resulting in failure. The oil supply pipe should also be checked to make sure that there are no obstructions.

All the dealers I've talked to are interpreting this bulletin to mean you only need to check the banjo bolt if the condition of the oil is questionable or you suspect long oil change intervals. Of course they will be happy to add it to your work order if you don't mind paying for an hour or two of labor.

[nka]

Changing oil at each 6000KM is a lot if you use good oil at 100$CAD (like Motul) per flush...

[Shik]

All the dealers I've talked to are interpreting this bulletin to mean you only need to check the banjo bolt if the condition of the oil is questionable or you suspect long oil change intervals. Of course they will be happy to add it to your work order if you don't mind paying for an hour or two of labor

 

Exactly, Mike. Say/admit to just enough to sort of cover themselves should your turbo die outside of warranty.

 

Oh well, at least they said that much I guess

 

I noticed at mysubaru.com, they mention nothing of checking the banjo bolt in "caring for turbocharged engine" article. Would that have hurt so much to make at least some kind of mention? Did original owners ever get any notice of the banjo bolt filter that it "should be checked"?

 

[BigBad]

Subaru has never at least in my experience notified owners of any TSB's. The only actual recall was the fan relay in which I got a letter for. Any TSB items I had brought my car in for were learned off this forum by those who posted them like L7.com

[SBT]

Wait - check this Turbo Mesh Screen TSB. They're clearly aware of it and have sent this out to their dealerships as well. My master tech was aware of it when I discussed this topic with him. We even pulled off my BB to check the screen it was perfectly fine.

[HAMMER DOWN]

Mccory, again, I am no expert, but no oil filter captures 100 percent of all particles. Most filters are designed to trap particles around 20 microns or larger. What happens when 2 or 3 or 4 microns continue to get built up on a mesh screen in a banjo bolt over a few thousands miles?

 

-Matt

 

Use this http://legacygt.com/forums/showthread.php?t=81741 and 2 microns wont be a concern.

 

Amsoil Ea filter info. https://www.amsoil.com/storefront/eao.aspx

 

Amsoil Ea By-pass filter info. https://www.amsoil.com/storefront/eabp.aspx