Walnut Blasting Intake Valves for 2015+ WRX FA20 DIT
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This is a discussion on Walnut Blasting Intake Valves for 2015+ WRX FA20 DIT within the Tutorials & DIY forums, part of the Tech & Modifying & General Repairs category; Hey everyone, I did this write-up on Nasioc but fortunately I saved the script so i don't have to do ...

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    Walnut Blasting Intake Valves for 2015+ WRX FA20 DIT

    Hey everyone,

    I did this write-up on Nasioc but fortunately I saved the script so i don't have to do it again. Hopefully the photo code is the same...if not...I'll paste the link to the original thread.

    Hey Guys,
    Decided to walnut blast my intake valves myself as I was curious to see how much gunk built up within my intake tract around 10,000 miles. Been seeing a lot within the forum community with regards to these DIT engines getting pretty dirty. Since this is fairly new with the Subaru community and BMW shops/dealers are the only ones who really do this type of services, I wanted to to get all the necessary equipment and do it myself.

    My car is a 2016 wrx and it has about 10,500 miles. I'm currently Cobb stage 1 with no engine related mods besides the Mishimoto dual oil catch can system. I will be getting TGV deletes after the winter is over along with a protune.

    Since doing the blast, I've noticed improvements in acceleration smoothness, no more white smoke from exhaust (which happened a lot), and improved fuel efficiency. I did a normal trip which is about 55 miles long today and noticed the average mpg was up 4.5 mpg during the trip. I went from about 30-31mpg to 35mpg.

    If anyone has any questions, don't hesitate to reply or PM me. I wanted to share this as this seems to not be a covered topic with regards to having it done. This is something you could do yourself if you have the equipment, the time and general knowledge with working on cars. I am currently offering this service for $400 (BMW dealers charge $500+). I also add in the cleaning of the TGV and EGR valves along with the intake manifold and anything else in the intake manifold path to the intake valve ports. I'm located in Massachusetts so you would need to live near by and to come to me.

    Needed
    • 20+ gallon and 4.5 CFM @ 90PSI Air Compressor & Shop Vacuum
    • Media blaster kit from Bavarian Autosport
    • Vacuum adapter for walnut blaster
    • Necessary tools such as screw driver, plier,torque wrench and socket set. (nothing special)
    • Jack stand or wheel ramps


    Step 1
    Jack car up. Remove top engine cover as well as plastic undertray. The undertray as a total of 13 pop clips and 2 bolts.



    Step 2
    Release fuel pressure. First undo cap from gas tank. Then remove the fuel pump fuse which is located in the engine bay fuse panel. The manual shows where this is. It's a #15 fuse. Start the car and run until it dies. Took about 2-3 minutes. Once it died, I tried starting again wit the gas pedal to the floor to make sure all fuel was gone. You can also use your Accessport if you have one to monitor fuel pressure. It will be down around 10 or so instead of in the thousands.




    Step 3
    Jack car up and remove peacock from radiator. Open up radiator cap to speed up process. Stop once you fill about 3.6 quarts (what manual says to remove intake manifold).



    Step 4
    Remove Intercooler 3 bolts with a bracket on right side along with the clamp for the hose on the right. loosen clamp on left side hose and 1 bolt at the top left.



    Step 5
    Remove the 2 gas lines on the right side of the intake manifold. The top hose has a little blue clip that you pull out in order to release the hose. Remove bottom hose too. Put a few rags underneath to catch any fuel. Only a few drops came out with no pressure whatsoever.



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    Step 6
    All this step involves is removing all of the hoses and electrical plugs from the intake manifold. Once you start removing the intake manifold, you will be able to spot if you missed anything. One tip is to buy assorted color makers and mark each end so you know what goes where. Subaru already does this with a few of the hoses from the factory but not all of them. Also, remove the EGR valve coming from manifold. Be careful as there is a metal gasket at the end of the first part of the EGR system coming from the manifold. The little hose adapter that the gas lines came from also needs to come out. You need to remove the bottom hoses from the little piece and one of them has a little clip you have to pull out too.











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    Remove TGV's too. When you do this, be very careful of the o rings. This is how dirty the intake manifold was at the ports




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    Step 7
    Remove this little styrophome piece near the driver side ports.



    Next, Remove the (Don't know the name of this) Must be part of the TGV assembly. 3 bolts. Be careful of the o-rings. They are black on the top of this unit and then orange on the bottom which connects to the head ports.





    Steph 8
    You will now be able to see the ports to the intake valves






    Remove the plates from the head ports.


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    This is what the intake ports and valves look like after 10,500 miles!!!! :diaf:





    Step 9
    You can finally now clean the intake valves!!!. I use a vacuum adapter from Bavarian autosport, No one makes one for the WRX so I guessed at a size which was a little too small but I used a piece of rubber to block any open space in the port. The wand from the blaster can fit within this little hole through the vaccum adapter so as you blast, the shop vac will suck up all the pieces while you work to make it less messy. A little mess happens but not as much as if you didn't have this adapter. This stuff shoots fast and goes everywhere if its open! :banana:
    To close valves, use tall enough ratchet that you can work while looking into the port with a flashlight. As you rotate crank clockwise from crank pulley, you will be able to see the valves open and close.





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    Starting to look cleaner... the surface face is still dirty. I didn't clean this until the end.





    Dirty, dirty, dirty!!! :diaf:




    start of looking clean, clean, clean!!! :ritz:





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    Step 10
    Once I was done with the intake valves and ports, I went to clean everything else such as the TGV setup, plates, EGR, and manifold. Make sure you remove all gaskets/rings!!!!! Forgot to take a picture of the intake manifold walnut blasted but I will tell you it is night/day clean compared to the pictures I took when I took it off all gunked up!




    Clean. You need to quickly wipe away any stuck walnut shell.






    Step 11
    Reinstall the plates and TGV assembly. Make sure all gaskets/rings are seated correctly. DO NOT USE RIPPED GASKETS OR INSTALL OUT OF LINE. Reinstall manifold and reconnect all hoses and plugs. Triple check that you didn't miss any and that they match up exactly. Take pictures, use assorted markers and write everything down as this is not a project you want to get wrong....




    Step 12
    Put fuse back for fuel pump in engine bay fuse box. Add coolant back in to radiator. Start the car up, let warm up. Check all around to make sure there are no leaks and that everything is working properly. Use accessport to monitor data if you have one. Take it for a drive and take a log. If you don't have an accessport, just drive it around and once warm, get on it to make sure everything is good. If I was able to notice the improvements I listed in the beginning of this post from only being 10,500 miles, if you have 30K+ miles, you will notice a huge difference.



    I wish i could do an EGR delete but being in Mass, emissions would be a pain to get through. I will see if my tuner can do something where I can avoid failing inspection. I truly believe that this new FA20 DIT platform is a great and big step forward for Subaru. Even when you come up with a brilliant idea for a new engine, there will be a few drawbacks that can affect the longevity...in our case it's the intake valves getting gummed up from not having any fuel mixture to clean the valves.

    The best first step is to get the dual oil catch can system. TGV deletes and EGR delete will also drastically slow down the build up from the manifold to the valves. A tune is also another must with these cars as the stock tune is crap..preaching to the quire, i know...

    Again, if anyone has any questions, concerns, additional info, feel free to post here, or PM me. I am available to do this in Mass. PM me for more info if interested.

    Hope this is helpful for everyone!

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    Registered User WRX John's Avatar
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    Impressive DIY Subie53!!! Both the work you did and the DIY itself that you created for us all. Thank you.

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    Good write-up. Everything cleaned up well.

    I would advise finding an air oil separator, it can help a good bit.

    Sent from my SAMSUNG-SM-G935A using Tapatalk
    All? NO ALL!

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    Quote Originally Posted by XJman View Post
    Good write-up. Everything cleaned up well.

    I would advise finding an air oil separator, it can help a good bit.

    Sent from my SAMSUNG-SM-G935A using Tapatalk
    Thanks, man! I decided to do the dual oil catch can system. No issues so far and accomplishes the same thing pretty much. Gonna do TGV deletes soon with a protune on my cobb stage 1 tune. Gonna find out if I can delete the EGR and if the tuner can make sure I don't fail inspection...if so, those 3 things combined should stop the build up pretty much...will obviously monitor over the next 1-3 years with pictures to see if all of this really works well.

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    Yeah it all helps quite a bit. Honestly there is so much crud in the air that it is inevitable. I'm having my tgv deletes put in soon because the factory units are leaking, I may ask about the egr delete as well.

    Sent from my SAMSUNG-SM-G935A using Tapatalk
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    Quote Originally Posted by XJman View Post
    Yeah it all helps quite a bit. Honestly there is so much crud in the air that it is inevitable. I'm having my tgv deletes put in soon because the factory units are leaking, I may ask about the egr delete as well.

    Sent from my SAMSUNG-SM-G935A using Tapatalk
    Yeah, TGV's deletes are great. EGR would be awesome if a pro-tuner can make it look normal so there are no inspection issues. Those gaskets that are part of the TGV deletes def need to be carefully handled. I was super careful when I removed all of them so I could blast the stock TGV's along with the whole manifold. You will def like the new TGV deletes!

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    Quote Originally Posted by WRX John View Post
    Impressive DIY Subie53!!! Both the work you did and the DIY itself that you created for us all. Thank you.
    No problem, man. Hope this will help people be proactive in helping eliminate/greatly reduce this from happening. This is all worthless if you don't add the necessary parts to help prevent this.

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