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Old 11-01-2015, 06:55 PM   #1
Unabomber
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OMGHi2U How to make j00 valves happy AKA great and sage DIT motor advice

I know what you are thinking, "Who the does Unabomber think he is....he may know WRX and STI stuffs, but he don't know FA/DIT stuffs". You would be right, but....I do keep my ears to the ground and have learned something to pass on. It's your call as to pay attention, rebuke me for rehashing old crap, or marveling at my brilliance as you see fit.

May I present the intake tract of a FA DIT motor @ 14,000 miles:



Now you are probably thinking, "ZOMGWTFBBQ!!!" and you should be. It looks like this motor ran maple syrup rather than gasoline and you are wrong. It's a normal stock daily driven late model WRX. Read the above again kids.....14,000 miles on the odometer.

Now for those of you evidence based folks out there, I have you covered as you are likely thinking, "What does this have to do with the price of tea in China?". I came upon this picture and theories, not on a renegade Facebook conspiracy site, but from my good buddy Kienan who owns a Subaru centric shop in Chesapeake, VA called All Aspects. He noticed that the newer WRX FA motors were a pain in the nuts to tune. Apparently, one can throw any map on an old EJ Subaru and it will run 90% the same from car to car but on these new FA motor'd cars, each car had different reactions and results with the same tune making them a pain in the nuts to tune compared to days of old. He wanted to find out why and drew upon his experience with the Direct Injected Mazda folks whom had/have intake gumming issues, so you get what we have pictured above: gumming intakes on DIT Subaru motors.

Now the Mazda folks apparently just run some SeaFoam every few thousand miles, but my buddy Kienan went for a more elegant solution: Walnut blasting to clean, EGR delete to kill the main cause, and water injection to continually clean/add more power.

The photo above is the before and here's the rig for walnut blasting:



It is a little rough, but the whole shebang is bolted to the motor with the top port being where the shopvac goes with lots of JB Weld to make it air tight and also hide the welds.

This is the same intact after walnut blasting:



Here is a good side by side of another motor with less than 20k before and after:



Another 14,000 mile motor of before/after:





35,000 mile motor of before/after:





Now aside from the above mentioned pain in the ass tuning, here's the real world example of why keeping the intake tract clean is important. This is a before and tuned car with a dirty intake and a after tuned care with a clean intake:



Can you say hello power everywhere? ***for you tuner dorks that want to hate on this plot, yes, there is a big dropoff in higher RPM attributed to other factors, this really is a dirty/clean comparo and not power proven bragging***

And when you add water/meth injection to the mix:



So what does this mean to the FA DIT crowd?

Know and own that your intake tract will get gummed up and you will lose power VERY quickly.

How can I fix this?

1. See if your local shop can do walnut blasting. My buddy Kienan charges $450 for this service as the whole manifold has to come off, the motor rotated, blasting, and repeat for all four cylinders. Expensive, but considering you gain 20HP, it's not bad.
2. Try some janky fix to clean the intake tract like SeaFoam. Will it work as good as media blasting? You'd have to pull the manifold to see with your own eyes.

How can I prevent the gook build up?

1. I polled many Subaru dorks and they are all pretty sure it is the EGR system. Yank that jank off. IAG makes an EGR delete kit that is crazy cheap and doesn't seem to be too bad of an install. The rough part is it will throw a code, so tuning of some flavor is required to fix the code. This Youtube video show both how to install an EGR delete kit and if you skip forward to 6:30 in the video, you'll see how gooky the whole EGR system gets after only 7000 miles.
2. There is also some secondary theory that says oil may be an issue and an AOS or catch can of some flavor would not be a bad idea.
3. Water/alky injection. Any cool liquid being misted on the backside of the valves will clean as you go and provide the ultimate protection as well as some more power.

And as an aside....if you are going to have the intake tracts cleaned via media blasting and have the EGR done at the same time, it is 1000% smart to just go ahead and throw TGV deletes into the upgrade path at the same time since the mechanic will be futzing with both the area where the TGV deletes go and with tuning it. Not required per se, but it makes a ton of sense to bundle these.
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Last edited by Unabomber; 12-09-2016 at 11:50 AM.
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Old 11-01-2015, 08:37 PM   #2
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Thanks Unabomber, definitely looking to walnut my car next service interval at 16k, EGR delete has been ordered. It's stupidly cheap for something that will immensely help the gunk build up.
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Old 11-01-2015, 08:42 PM   #3
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Originally Posted by TheSilentCircus View Post
Thanks Unabomber, definitely looking to walnut my car next service interval at 16k, EGR delete has been ordered. It's stupidly cheap for something that will immensely help the gunk build up.
When I do all my upgrades I will be getting walnut blasting, egr, tgv and then tune. At that point I want to have the EBCS, intercooler, charge pipe, water meth and fuel pump, knock it all out at once so I don't have to tune the car 3 or 4 times.
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Old 11-01-2015, 08:44 PM   #4
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Ya **** that, I'm not spending what ever they charge here in Canada and having my engine ****ed with every year for this. I'll just wait until it's off warranty, delete the EGR, maybe a few upgrades, clean the valves and get a tune all at once. Thanks bomber, good read.
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Old 11-01-2015, 09:15 PM   #5
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Quote:
Originally Posted by ryager View Post
When I do all my upgrades I will be getting walnut blasting, egr, tgv and then tune. At that point I want to have the EBCS, intercooler, charge pipe, water meth and fuel pump, knock it all out at once so I don't have to tune the car 3 or 4 times.
Thanks for the brain bump as if you are doing the blasting and EGR, it's actually kinda silly to NOT DO the TGV deletes, I'll edit above.
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Old 11-02-2015, 02:22 AM   #6
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Is there someone that offers this service in southern California yet? If not, has anyone tried seaform yet?
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Old 11-02-2015, 04:10 AM   #7
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Quote:
Originally Posted by ryager View Post
When I do all my upgrades I will be getting walnut blasting, egr, tgv and then tune. At that point I want to have the EBCS, intercooler, charge pipe, water meth and fuel pump, knock it all out at once so I don't have to tune the car 3 or 4 times.
Pretty much going to do the same thing sans the water meth! Hopefully all my Stage 2 parts come in by that time.

Quote:
Originally Posted by jpy1980 View Post
Is there someone that offers this service in southern California yet? If not, has anyone tried seaform yet?
I looked around and have seen a lot of BMW garages do the service. I'm trying to talk to some garages right now and am currently waiting to hear what they say. If you find one definitely let me know!
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Old 11-02-2015, 07:20 AM   #8
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Is there someone that offers this service in southern California yet? If not, has anyone tried seaform yet?
You could always print out that rig I pictured above and ask your local Subaru shop to make one and offer it as a service. Its one of the reason why I shared the rig...to copy
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Old 11-02-2015, 11:23 AM   #9
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You have my approval to Sticky this Big Ron.
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Old 11-02-2015, 12:46 PM   #10
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Great write up, some of which ive seen or knew already. Esp since ive been around the mazdaspeed world.

It would be amazing if shops could bundle all of these amazing products into one package (or two). Say, buy the egr/tgv deletes, aos and walnut blast..then tune her up and send you on your way. Id def be down.

For now though, Ill start putting my money to the side for this. Reliability is key!
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Old 11-02-2015, 03:12 PM   #11
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Thank you for the detailed and informative post. As for the EGR delete, it looks like it needs a tune to turn off the CEL, but can we run without a tune? I would like to gather a few more parts before protune, however, would like to decrease the build-up issue ASAP.
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Old 11-02-2015, 03:47 PM   #12
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Thank you for the detailed and informative post. As for the EGR delete, it looks like it needs a tune to turn off the CEL, but can we run without a tune? I would like to gather a few more parts before protune, however, would like to decrease the build-up issue ASAP.
It is not just turning off the codes. Anjuna has a whole post on this, there is more to do than just turn off codes though. He has the tables posted so if you have Access Tuner Race then you can just turn off the codes with your OTS map and then do what Anjuna says to do. I am pretty sure you copy and paste the EGR tables together, do not want to go to far into it because I do not remember exactly what to do and I do not want to give wrong information.
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Old 11-04-2015, 01:27 PM   #13
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Sorry to sound like a newbie here. But I have been reading about this DIT carbon build issue. You are mentioning EGR as the source of the problem. However I thought most were attributing PCV as the source of the carbon build up. If you had oil in your exhaust gas I would think you have more serious issues at hand. Plus isn't EGR only functional when the vehicle is warming up, then completely closed off? Can anyone explain further why this write up is pointing to the EGR?

Thanks!
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Old 11-04-2015, 01:35 PM   #14
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I had mine cleaned at AAM a few weeks ago.

My thread.
http://forums.nasioc.com/forums/show....php?t=2752551

Different driving styles will most likely reflect different looking valves. Mine looked better than some of the low millage pictures. However, regardless, I think it's worth investing your money into maintaining them. The added power of meth (I gained over 50whp just from meth) is worth it while they have the manifold off for cleaning. Not everyone has access to AAM but those who are in the surround VA area, I would recommend. Kienan and Eric were great people to work and talk with.
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Old 11-04-2015, 01:39 PM   #15
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Quote:
Originally Posted by buschman View Post
Sorry to sound like a newbie here. But I have been reading about this DIT carbon build issue. You are mentioning EGR as the source of the problem. However I thought most were attributing PCV as the source of the carbon build up. If you had oil in your exhaust gas I would think you have more serious issues at hand. Plus isn't EGR only functional when the vehicle is warming up, then completely closed off? Can anyone explain further why this write up is pointing to the EGR?

Thanks!
You are thinking of TGV. EGR is always functional. It's designed to burn off the N0x gas. I know nothing about it outside of tearing it off and looking at it. It looks like it's designed to recirculate burnt exhaust. There was an electrical plug to the valve so I am assuming once the valve reaches a certain temperature/pressure or some sort of reading it will open, pushing the exhaust gas back into your manifold to reburn it again to make sure the gases are burnt out. So take a minute and think about how dirty the tips of your exhaust gets with a stock tune. Then imagine them when you get a protune. Then imagine that dirty exhaust not only getting push out of the rear of your car but back onto your valves. I highly doubt the FA has enough blow-by oil to be a huge contribution to build up. I would do an EGR delete well before a OAS/catch can if I was worried about build up. There was A LOT of slugged build up just on the rim of the EGR port when I rubbed it with my fingers after removing it. I can imagine this becoming a sticky, tar like substance on the valves and intake.
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Old 11-05-2015, 05:47 PM   #16
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Originally Posted by Wireeater View Post
You are thinking of TGV. EGR is always functional. It's designed to burn off the N0x gas. I know nothing about it outside of tearing it off and looking at it. It looks like it's designed to recirculate burnt exhaust. There was an electrical plug to the valve so I am assuming once the valve reaches a certain temperature/pressure or some sort of reading it will open, pushing the exhaust gas back into your manifold to reburn it again to make sure the gases are burnt out. So take a minute and think about how dirty the tips of your exhaust gets with a stock tune. Then imagine them when you get a protune. Then imagine that dirty exhaust not only getting push out of the rear of your car but back onto your valves. I highly doubt the FA has enough blow-by oil to be a huge contribution to build up. I would do an EGR delete well before a OAS/catch can if I was worried about build up. There was A LOT of slugged build up just on the rim of the EGR port when I rubbed it with my fingers after removing it. I can imagine this becoming a sticky, tar like substance on the valves and intake.

Interesting. TGV is tumble Generator Valve correct? I though this was just some obstruction in the intake track to cause turbulence to the incoming air. I forget the perceived benefit of this, but I understand how some see this as restricting airflow.

The EGR, Exhaust Gas Recirculation, on my old f-body was only function while the engine was below a set operating temperature. This would bring the engine up to temp faster and thus better for emissions and potentially gas milage? I would think the issues from constantly running the exhaust gas through the intake would far outweighs the emissions gains. Could they not just run more efficient cats? That's a question for Subaru engineers I suppose.

However, I completely understand your point about what those exhaust fumes must do the the intake tract. Not a fan. I will probably look to do an EGR delete if I pick up a 2016.

So you are saying I am off base in the understanding that much of the issue with the DIT engines is that the PCV is introducing Oil vapors into the intake tract and there is no longer full being sprayed on the intake valves to keep it clean. That is my understanding of the issue. Perhaps I am using the wrong acronyms.

I would assume the EGR valve is an issue for all engines. I just thought with it only being used at startup, until the engine got warm(at least in 4th gen f-bodies) that this had a minimal affect. The PCV is the bigger issue for the DIT engines because the inject is inside the cylinder.

Thanks for sharing your info. The more I learn, the less I feel I know.
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Old 11-05-2015, 06:37 PM   #17
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Go here for pictures of my egr and valves.

http://forums.nasioc.com/forums/show...php?p=43857577


The build up you see on the EGR parts is the same build up you find in the intake track and valves. I ran my finger inside the manifold port that the EGR contacts to before blocking it off and it was the most disgusting amount of tar and residue on my gloves just from on swipe.
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Old 11-30-2015, 01:00 AM   #18
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My local Subaru dealer recommends Terra Clean a service they provide but only recommend at 60,000KM, yet in Australia they perform this or recommend every 12,000km. Oddest difference was told due to climate, would the buildup be even worse in a hotter climate, I guess it could be.

I just bought the egr/tgv delete kit, and also plan to install Crawford AOS that I have when I get pro tuned. However I am not looking into dropping the coin required at this time to do prior to the pro tune, I am just approaching 12000 miles.

Terra Clean service, can anyone comment, dealer said works well cost was reasonable, if so I would consider just before my Protune?

http://terraclean.net/product.php?id=54

http://terraclean.net/pdf/GDI%20Inta...0Procedure.pdf

Last edited by Cisco Kidd; 11-30-2015 at 01:07 AM.
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Old 11-30-2015, 11:00 AM   #19
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A better question is this.....

We all know Subaru was not first to market with the DIT and ALL dit motors have this issue even those combining direct injection and port injection. However both can help where port injection will help clean the exhaust valves.


BUT I would think that Subaru knew about this problem, but WHY did they not integrate it into their service program? I have heard that BMW actually offers this as part of their maintenance program but Subaru didnt....?
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Old 11-30-2015, 12:04 PM   #20
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Quote:
Originally Posted by shamrock 05 View Post
A better question is this.....

We all know Subaru was not first to market with the DIT and ALL dit motors have this issue even those combining direct injection and port injection. However both can help where port injection will help clean the exhaust valves.


BUT I would think that Subaru knew about this problem, but WHY did they not integrate it into their service program? I have heard that BMW actually offers this as part of their maintenance program but Subaru didnt....?
Maybe they feared it would turn away sales. Why not sell all the cars first THEN introduce the service later once everyone starts getting into the higher millage.
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Old 11-30-2015, 03:52 PM   #21
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Quote:
Originally Posted by Wireeater View Post
Maybe they feared it would turn away sales. Why not sell all the cars first THEN introduce the service later once everyone starts getting into the higher millage.
Well it sucks because I will have to try and find a subaru friendly shop that has the means of walnut blasting to blast the exhaust valves, at what milage?.....I have no idea.
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Old 11-30-2015, 06:45 PM   #22
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Quote:
Originally Posted by Cisco Kidd View Post
My local Subaru dealer recommends Terra Clean a service they provide but only recommend at 60,000KM, yet in Australia they perform this or recommend every 12,000km. Oddest difference was told due to climate, would the buildup be even worse in a hotter climate, I guess it could be.
Im from Australia and just had my 12,000km service. They asked me if I wanted 1 extra fuel additive which wasnt included in the capped price servicing but they strongly recommended, I said yes. I have attached the receipt they gave me afterwards and a picture of the fuel additive they said to add again half way between the next service. But by the very definition of a 'fuel' additive it cant be preventing the carbon buildup of the intake valves as fuel never touches them!

The only thing that could possibly help is the "1x Cleaner Upper Engine ALLMODLS SUSA459".

https://goo.gl/photos/JgWsD3UjbMdGAWXX6
https://goo.gl/photos/3VikrGC1Si5SDJY69

Thanks for a great thread Unabomber, I already have the egr deleted and catch cans setup (although the catch cans have not caught a drop of oil yet).

There was a really detailed link provided in another thread here from a BMW owner who went through all this process, he concluded that no spray cleaner was able to move the carbon buildup on the intake valves and the only way he found that worked was the walnut blasting. He also had dynos before and after proving a big difference.

Last edited by Harey; 11-30-2015 at 06:54 PM.
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Old 12-02-2015, 07:56 PM   #23
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What do you mean the engine has to be rotated? Do you mean rotate the crank until the valves are closed?
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Old 12-02-2015, 09:55 PM   #24
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What do you mean the engine has to be rotated? Do you mean rotate the crank until the valves are closed?
Yes sir
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Old 12-03-2015, 03:56 AM   #25
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Does anyone know if this Subaru code is Terra Clean: "Cleaner Upper Engine SUSA459"?
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