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Carbon Buildup

6994 Views 22 Replies 9 Participants Last post by  CrypTech
I've learned so much these past few months after being hired on by kia as a technician. One thing I've been seeing on these GDI engines is extreme carbon buildup on the intake side and even the tops of the pistons at mileage as low as 15k. Well one of the main causes of this is the dreaded recirculation hose off the cam cover. This carries air with oil contaminates back into the air intake pipe. So on my personal car I added a high flow mini air filter on the end of that hose instead of running it back into the intake. Now doing this has now made my car a little more impractical, this mini filter gets diry pretty quickly but it's the only thing I can think of..What do you guys think? You guys have any ideas?
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Catch can? I think there is the pvc hose that connects to intake manifold that is more of a problem. ... it needs the vacuum though so you need a catch can for that....
I have 2 add w1 cans. I got both for 160 shipped and they have been perfect
I have 2 add w1 cans. I got both for 160 shipped and they have been perfect
Do you have pictures of this set up?
This makes sense when I pulled my turbo off I had alitle bit of oil at the turbos inlet
Yes i do! I will post pics when i get on my laptop in about 20 min
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Ok here are a few pics of the setup. I also added what 1 week does with the can lol Take note that I am boosted and I am trying different spark plug gaps. The can smelled like a mix of oil and gas so I am guessing my gap was to small so now I am trying to go a tad wider.

This is the breather one off the valve cover

Don't mind the clear hose. I am going to be putting a breather filter on the can so that hose will be gone soon
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This is perfect thanks for sharing! I'm definitely going to get something like yours asap.
No problem. I recommend everyone getting the cans asap.

Also i ment to say that i am tuned not boosted.
I wish they weren't so damn expensive
Yeah they are pricey. I paid 160 for both
Also keep in mind, GDI engines inject fuel directly into the combustion chamber, not the intake. Conventional MFI sprays fuel right at the back of the valve which "rinses" the small amounts of oil that drips past the stem seals and guides. GDI doesn't. Which will result in some (read: Alot) of carbon buildup on the intake valves and some on the piston heads. Kia supposedly says adding some techron additive will help keep the build up to a minimum though id rather do a light intake/top engine cleaning every 15k to be sure.
I remember reading in the manual that KIA recommends to use a fuel system cleaner, so maybe this is their combative against carbon build up?

I throw in a bottle of gumout fuel cleaner every oil change in my wife's optima and my koup
A fuel system cleaner wont do anything for the valves as fuel never goes there. Most manufactures have what they call an induction service that basically is to clean out the intake manifold and valves
^ Pretty much this. Though id lean towards using a quality grade full synthetic oil over a conventional or even semi-syn blend. Full synthetics have a much higher resistance to coking and becoming hard carbon lumps.
Yeah they are pricey. I paid 160 for both
Any photos of where these are hooked up at?
Dont have any but one is connected to the breather on the valve cover. The other is to the pcv valve that on the lower right corner of the valce cover. I will try to get some tonight though
^ Could also take a peak over on veloster forums as I think there is many pictures and threads on catch cans there as well.....
Old topic but I found this video very informative and wanted to share..

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