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Old 12-21-2015, 10:40 PM   #51
ArmyOfSkittles
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Quote:
Originally Posted by shadow_772 View Post
So far the theory for these seems to be walnut blast and delete the EGR. AOS may help, but its debatable.

Youll get this same answer pretty much everywhere you go. Egr delete on its own is 50$ and delete a check engine light. Imo, egr is the biggest contributor to the build up. 300-400$ for an AOS and you shoild be done. Thats 500$. If that lets you go 2 years without walnut blasting then you saved money. AND if thats not enough, havingn clean intake valves will probably save you a few dollars im gas a month, too
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Old 01-02-2016, 12:15 PM   #52
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Originally Posted by mdaygo View Post
Terra Clean appears to be a bit more involved than just spraying something in your intake.

http://www.terraclean.net

Specifically:
http://terraclean.net/product.php?id=54
Yes it is, I am approaching 14K miles, I now ahve all my parts for my stage 2 and plan to be tuned soon on dyno. The service here in BC canada is about $250 w tax. Since I will be doing EGR and Crawford AOS I figure this may be worthwhile prior to dyno. From reading about it the method does a good job in cleaning the intake valves
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Old 01-03-2016, 01:07 PM   #53
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I see how deleting the EGR would certainly help with carbon build up; no question there.

I'm having a hard time understanding though how and AOS/catch can won't have as much, if not more, of a positive effect on intake valve build-up after installation. Sure, the valves shown in the "before" pics have carbon on them but what I see more of in those pics is oily, gunky build-up that resembles something that could be prevented from a decent AOS or catch can.

I'm leaning towards the idea that a valve cleaning and an AOS/catch can would have a greater overall preventative effect than a valve cleaning and EGR delete.
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Old 04-11-2016, 11:25 PM   #54
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Any update on this?
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Old 04-12-2016, 09:17 AM   #55
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Any update on this?
An update on what?
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Old 04-14-2016, 11:51 PM   #56
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Install a meth injection kit and it shouldn't be a problem.
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Old 10-19-2016, 09:08 PM   #57
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Great post, with real science. I like it. Thanks for this!
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Old 11-11-2016, 12:38 AM   #58
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Great read, thanks again for excellent info!
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Old 11-15-2016, 09:19 AM   #59
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Quote:
Originally Posted by Harey View Post
The EGR is purely an emissions device.

The downsides to deleting it are:
- any legal/emissions ramifications
- you need to disable error codes on the ecu
- potential for impacting a Subaru warranty claim

There are no technical downsides to removing the EGR.
This is true for diesels. For gasoline engines, it impacts emissions, gas mileage, and time to torque.

A tune would be necessary because EGR will impact manifold pressure.

Gas mileage would go down because you are taking out unburned fuel/hydrocarbons from the mix. The hot EGR gases also help atomize the A/F mixture.

Time to torque would actually improve with a delete kit since you get less inert gases mixed in with the A/F.

And yes, any OEM that runs EGR has to deal with varying degrees of fouling. Toyota had issues with their previous gen Priuses.
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Old 11-17-2016, 11:00 AM   #60
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Quote:
Originally Posted by ArmyOfSkittles View Post
I listened to Big Ron. @ 14,000 miles
http://forums.nasioc.com/forums/show....php?t=2764797


Is the dyno sheet a before and after result of your carbon cleaning or a separate tune you had done?
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Old 12-09-2016, 10:15 AM   #61
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Originally Posted by steverx05 View Post
Is the dyno sheet a before and after result of your carbon cleaning or a separate tune you had done?
Bump Bump
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Old 12-09-2016, 10:16 AM   #62
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Thank you for the post Unabomber
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Old 12-09-2016, 10:31 AM   #63
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Also would like to contribute here...

2016 WRX, just hit 25K miles yesterday and I have noticed a SIGNIFICANT drop in gas mileage over the pas 15K miles. I have not inspected my intake tract but I'd imagine it's similar (if not worse) to the pics posted.

There's also a great install viedo on EGR deletes showing the accumulated gunk on a LOW mileage (7K miles) 2016 WRX from a channel I follow. Skip to 6:30 to see buildup.

https://www.youtube.com/watch?v=Sgx0vNtnoRw
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Old 12-09-2016, 11:52 AM   #64
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Added video to first post....never thought to post what the EGR thingy looked like as well. While it is just a bunch of internet nerds with internet theories....the EGR looks to be the main cause of all the gook.
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Old 12-09-2016, 12:32 PM   #65
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One more look at the EGR system pulled out of the engine.... short and informative.

https://www.youtube.com/watch?v=yoOhNPQ3Uzc
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Old 02-25-2017, 05:34 PM   #66
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Quote:
Originally Posted by Unabomber View Post
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.
Thanks for putting this sticky together.Read it way back and was part of my drive to walnut blast my valves. Check out the following thread I made on doing it which goes though the process in pretty good detail!

https://forums.nasioc.com/forums/sho....php?t=2828928

Jon
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Old 04-02-2017, 02:55 AM   #67
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Originally Posted by jpy1980 View Post
Is there someone that offers this service in southern California yet? If not, has anyone tried seaform yet?
Seems European Autowerks in Temecula offers the intake walnut shell blasting. Please note, I have not called to verify pricing or turn-around time. However, being the owner of a '17 WRX, I anticipate having to use their services at some point in the future.

http://www.european-autowerks.com/Mo...la-murrieta-ca
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Old 04-08-2017, 03:14 PM   #68
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Quote:
Originally Posted by Waddlz View Post
I used to own a 2008 Cobalt SS, which is a Direct-Injected motor. We found that walnut blasting and then adding a quality AOS was key to reducing/preventing this buildup.

Seafoam did nothing to help clean this.
same here, had the same car, loved it, beat on it, blew it up, fixed and beat it up some more
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Old 04-17-2017, 06:46 PM   #69
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For anyone curious, here were mine at 14.5k when my engine blew (scroll down) https://imgur.com/a/xAagr
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Old 04-18-2017, 08:54 PM   #70
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I think I've read all the FA threads on TGV and EGR deletes. Why is it a bad idea to remove your TGV but leaving your EGR?

I'm kind of leaning towards TGV delete + unplugging EGR with a tune to remove the codes.
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Old 04-18-2017, 09:40 PM   #71
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Originally Posted by RussianTiny View Post
I think I've read all the FA threads on TGV and EGR deletes. Why is it a bad idea to remove your TGV but leaving your EGR?

I'm kind of leaning towards TGV delete + unplugging EGR with a tune to remove the codes.
http://forums.nasioc.com/forums/show...2&postcount=57
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Old 04-20-2017, 03:35 PM   #72
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Great read man! much appreciated. I installed an EGR delete and a vent to atmosphere air oil separator at about 10K but im still going to pull the manifold to take a look.
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Old 07-25-2017, 02:22 PM   #73
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I think I've read all the FA threads on TGV and EGR deletes. Why is it a bad idea to remove your TGV but leaving your EGR?

I'm kind of leaning towards TGV delete + unplugging EGR with a tune to remove the codes.
Just unplugging the EGR will cause its' own issues. You'll want to do a block off kit with a tune.

As for the TGV delete it will kill your gas mileage without a proper tuning and the EGR delete. It will net a bit of top end power more so on the WRX than my FXT. Without the EGR delete it doesn't keep your valves cleaner. EGR Delete kit is cheaper than the TGV kit.
There is a link a couple of posts up showing people figuring out how to tune for the combination properly and why you have to do both at once in order to get a smooth tune.

When we were attempting to get my Stage 2 dialed in I came across some interesting readings on my TGV's. After discussing it with my tuner I did the TGV deletes re-ran the car on the dyno to dial in the tune and I was actually making less power. We thought it may have been bad tank of fuel...After taking a hit on my gas mileage in my daily driving and doing a lot of research on the FA20DIT TGV's I decided to put them back in the car.

The older Subies that had TGV's were basically closed on startup and open fully when the car was up to operating temp.

"The FA20DIT has separate timing maps for TGV open and closed, and we can see major differences in low load areas. The dynamic advance maps (which are added on top of the base values, depending on knock activity) for TGV open and closed are pretty close at lower load areas where the TGV is actually used."
So in short they help with knock prevention at lower loads. i.e. cruising at 70mph on CC.

More great info on how the FA20DIT systems work compared to the EJ motors and where the quoted text came from are found here:
https://forums.nasioc.com/forums/sho....php?t=2687550


I personally had my mechanic take a good look at my valves so see if we needed to walnut blast them. Fortunately no. I added a Crawford AOS but may be switching to either the IAG or Radium setup if I can afford it after fixing the rest of my current issues....

As for SeaFoam they make a specific top end cleaning product it has a long tube with a corner hook built into it. It is made to go into the hose that comes out of your intercooler feeding the throttle plate. I did this clean once which is probably why my valves didn't look really gummed up. Warning if you are running an upgraded TMIC, like I am, it can be a pita to get the tube past the bigger hose barb compared to stock. Some people on youtube have made adapters to inject it through the MAP sensor hole. This however defeats cleaning the throttle plate and also makes a more uneven disbursement of the cleaner throughout the rest of the intake system. I also bought the Subaru top end/fuel system cleaning kit. It's comprised of a gas additive, a throttle body spray cleaner and a vacuum line additive to clean the rest of the top end including the valves. The kit was like $15 but finding the darn "tool" to connect to the vacuum system and the price seem kind of extreme for a check ball valve, a coat hanger, a vacuum tube and fitting. I figured I could piece together my own it if necessary.

Last edited by freakshow999; 07-25-2017 at 03:58 PM.
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Old 08-18-2017, 11:44 AM   #74
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I emailed SOA and asked if a valve cleaning service would be offered in the future and this was the response.

Hello J :

Thank you for taking the time to contact Subaru of America, Inc. and congratulations on the purchase of your 2016 WRX Premium Sedan.

As long as you take care of your routine maintenance, you will not get carbon buildup on the valves. Older direct injection systems that experienced carbon build up were so called “lean burn” systems. Unfortunately these systems suffered many times from uneven combustion due to variations in the fuel and air mixture throughout the combustion chamber. This created a mix of lean and rich conditions resulting in variations in combustion temperature and uneven burning of the gasoline. This uneven burning lead to the condensing of unburned and partially burned hydrocarbons which over time resulted in carbon buildup.

Subaru engineers understood this when they created our current direct injection system. They developed innovative yet simple systems to manage and control the combustion variations inside the combustion chamber. These include features such as specially shaped piston crowns, multi-patterned injection spray, and tumble generator valves. All of which promote the precise swirling and intermix of fuel and air under the variable conditions required across the full range of power requirements. When combined with very high fuel pressures and extremely short injection duration of the Subaru direct injection system, stoichiometric combustion is maintained across the combustion chamber resulting in very even and complete burning. As a result abnormal residue and carbon deposits are not created and engine performance and fuel economy are maximized.

Thank you, J, for the opportunity to be of service. Happy Holidays.

Sincerely,

John J. Mergen
Subaru of America, Inc.
Customer/Dealer Services Department
1-800-SUBARU3 (1-800-782-2783)
Service Request Number: 1-12875529303

I don't think they want to admit an issue exists yet.


Hahahahahahhahahahaha omg. Talk about your typical engineered bulls*** response. "Our systems are perfect with no flaws whatsoever, even if it's the exact same as other systems with the same flaws" lollllll makes me wonder if any of the engineers over at Subaru have ever even changed their own oil. Everyone start flooding SOA with pics of your intake tracts, annnnnd go!!
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Old 09-15-2017, 09:04 AM   #75
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Hahahahahahhahahahaha omg. Talk about your typical engineered bulls*** response. "Our systems are perfect with no flaws whatsoever, even if it's the exact same as other systems with the same flaws" lollllll makes me wonder if any of the engineers over at Subaru have ever even changed their own oil. Everyone start flooding SOA with pics of your intake tracts, annnnnd go!!
I'm blown away that they responded in the way they did, to be honest. That's a straight-up press release.

The key word they used here, the lawyer-approved million dollar word is:

"As a result abnormal residue and carbon deposits are not created"

So deposits and residue happen, but there's normal, and then there's abnormal. You can show them the pics and they'll call it normal.

My feeling so far is that I haven't seen any alarming buildup pics yet. Someone mentioned here before - the most important thing to understand is whether deposits grow indefinitely or plateau at a reasonable point. But reasonable would be no discernible power or efficiency impact. I wouldn't be thinking about this at all if it weren't for the before/after walnut blast dyno. That tells us that even minimal deposits can have a surprising impact.

I'm in camp "wait and see." My fuel econ is same as it always was, butt dyno says all systems green. I'm at 35k mi, been using low SAPS oil which should be helping to keep the EGR a little cleaner. Is it possible to get a borescope to the valves without significant disassembly?


*edit* I borrowed a borescope and went into the manifold at that central sensor port. Couldn't see anything! This was the best image I got, and I'm not even sure it's actually a valve



I'm going to keep on trusting that my M1 5W30 ESP is keeping things clean

Last edited by fredzy; 09-19-2017 at 10:54 AM.
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