[avayswavay]

I'm coming over from a 16' VW GTI Manual with the performance pack. On the VW platform, I experienced a ton of carbon buildup at 60k miles causing misfires, cylinder shutdown, and deadly rough idles. As the Veloster N [PP] is still a GDI engine wanted to get out ahead of the Carbon Buildup this time with a Mishimoto Catch Can. The Can was developed for the Veloster Turbo as the bracket is mounted very near where our turbo and downpipe are. I relocated the can near the coolant tank and everything else was a plain and simple install. I was impressed with the quality and packaging of the Mishimoto can and as it has a micron filter it was an easy choice for me to make. I have seen some talk that these engines won't experience much carbon buildup and there is no need for a can but I'm not buying it at all. I already see oil on the valve cover nipple and in the PCV tube going into the intake manifold. As a mechanical engineer who once worked for automakers in Detroit, engineers decisions arent always driven by reliability and delivering the best product. One has to consider logistics, cost, marketing, etc etc. None of these automakers are looking to protect every single part of the motors they are producing. Especially when typically, Americans only own their vehicles for 3 years. I will be tracking the oil buildup in the can every 1-2k miles for the time being. I had a dispute with the dealer over some defective PZero tires on the N and was trying to wait to mod it at all. But I'm already at 2k miles and I fear the carbon. The carbon is to be feared and respected lol. Will keep updates on can results. Hope the attachment images dont blow up anybodies screen.

 

[wraaa]

I look forward to hearing updates after 1-2k miles - I've got a question for you regarding carbon buildup, italian tunes, and what not..

I've heard it stated definitively that Italian tuneups don't work on GDI cars because the fuel never touches the top side of the valves as its sprayed direcltly into the cylinder - my question is why? I will break it down into assumptions:

assumption 1) The way I understand it, the way port injection engines keep their valves 'clean' is a result of the gasoline constantly washing over the valves, which acts as a solvent for the carbon. Since a GDI engine goes direct into cyl, this doesnt happen.

assumption 2) Carbon deposits form naturally as a result of normal easy driving operating temperature, and the italian tune up 'works' by heating up the operating temperature to the point where it breaks down the carbon.

Question: Wouldnt the italian tuneup still keep the "cylinder-side" of the valve clean? while the "intake side" shouldnt be exposed to carbon because its supposedly in its closed position during the combustion process?

I am clearly fundamentally misunderstanding something - since you're a mech E perhaps you can break it down. Thank you

 

[avayswavay]

I look forward to hearing updates after 1-2k miles - I've got a question for you regarding carbon buildup, italian tunes, and what not..

I've heard it stated definitively that Italian tuneups don't work on GDI cars because the fuel never touches the top side of the valves as its sprayed direcltly into the cylinder - my question is why? I will break it down into assumptions:

assumption 1) The way I understand it, the way port injection engines keep their valves 'clean' is a result of the gasoline constantly washing over the valves, which acts as a solvent for the carbon. Since a GDI engine goes direct into cyl, this doesnt happen.

assumption 2) Carbon deposits form naturally as a result of normal easy driving operating temperature, and the italian tune up 'works' by heating up the operating temperature to the point where it breaks down the carbon.

Question: Wouldnt the italian tuneup still keep the "cylinder-side" of the valve clean? while the "intake side" shouldnt be exposed to carbon because its supposedly in its closed position during the combustion process?

I am clearly fundamentally misunderstanding something - since you're a mech E perhaps you can break it down. Thank you

So I will speak to this carbon buildup issue from my understanding of the concept and also from my own personal experience. Unfortunately I am no chemical engineer and carbon buildup, molecular breakdown and etc. fall out of my range of expertise. Carbon buildup is all about temperatures. Theoretically the Italian tune up works because of the concept of heating up components in the engine so high that the carbon actually separates and is removed on a molecular level. So in theory if you can get your engine hot enough the carbon WILL come off. The issue however is achieving these temperatures. I assume the only way to actually remove a good amount of carbon on intake valves, pistons, fuel injectors etc. you would have to be thrashing the car pretty hard on a race track for a long period of time. You are correct in stating that normal driving leaves a lot of carbon buildup because while "normal" driving engine components are usually within the range that carbon pre deposit likes to form and then carbon builds and builds. Gasoline that acts as a solvent on port injected cars constantly washes away this carbon pre deposit keeping carbon from ever having the chance to buildup.

Now as far as my own personal experience I mentioned how I suffered baddd from carbon buildup on my 16' GTI. Like so bad the intake valves were COATED. The tops of the piston were completely coated, my fuel injectors almost completely clogged etc. I first noticed cold start missfires and a rough idle. At first I thought the spark plugs were cooked...and they were. Changed the plugs, and while the issue got better it did not go away. Immediately I'm like okay cool let me try this Italian tune up. I grabbed a bottle of gumout and pounded on the GTI for like 30 minutes driving HIGH in the rev range most of the time. I did this twice. Cold start missfires were gone but missfires were still occurring at about 2K rpm. I was actually able to knock some carbon off the center of the pistons which makes sense because that is the hottest part of the piston. Sadly 2 weeks later cylinder 2 shut down as the fuel injectors had died a slow death lmao. Dealer said carbon buildup was so bad on my intake valves I couldn't even walnut blast it. Had to be chemically hand cleaned, quoted me $1700 dollars.

I say alllllll that to say , with pistons, injectors, and "intake" side of intake valves covered in carbon I imagine the other side of the valves were covered too, but this is just an educated guess. Mind you I ran Shell V-Power ultra mega 9500 whatever the **** they call their 93 octane fuel for the entire 60K I had the vehicle and....it didn't do much. Will ask dealer how sensitive injectors are and if I can run a fuel cleaner every 6K miles in the Veloster N as this is stated in the owners manual for countries that do not have high detergent gasoline. At least I can slow down the issue with catch can and fuel cleaner. Not expecting a knowledgeable answer from the dealer though as these guys are clowns. Most dealers know less about these cars then we do. So that's my story, and carbon is my enemy.

By the way Mishimoto found roughly 20ml of crud in their can on a Veloster Turbo

https://www.mishimoto.com/engineering/2019/05/2019-hyundai-veloster-turbo-catch-can-part-2/

Granted it is the Gamma engine but I am still curious enough to document the issue on the Theta 2. We shall see!

 

[VelosterRaptor]

So correct me if I am wrong; what you are saying is that I can avoid this problem by caneing the car as hard as possible in every single scenario like a hungry jockey on an aged horse?

 

[avayswavay]

So correct me if I am wrong; what you are saying is that I can avoid this problem by caneing the car as hard as possible in every single scenario like a hungry jockey on an aged horse?

😂😂😂 I wish this were the case. Dunno if this engine design will allow for sufficient heat internals for carbon removal. But I drive like that anyway so I'll let you know what I find 😂. Pcv systems like alot of others are to satisfy ever stringent emission requirements. So most of these manufacturers want to meet requirements at the cost of other things... cost , reliability , servicability etc. TBH just vent everything to atmosphere , problem solved .. it's illegal though .. at least in the US 😂

 

[udelslayer]

I'm surprised they can't invent a coating on intake valves and intake runners that prevents carbon buildup. Maybe that As Seen On TV Red Copper junk. With only 20 easy payments of 299.95, you can get a MAGIC INTAKE! I mean, if cheese doesnt even burn and stick to it, nothing will.

 

[RedVN]

So correct me if I am wrong; what you are saying is that I can avoid this problem by caneing the car as hard as possible in every single scenario like a hungry jockey on an aged horse?

Run it hard, yes absolutely and avoid stop and go short traffic runs. Catch can no, not really. There is such a small amount of fuel dilution in the oil, with this engine, it's not really necessary. You won't see more, until you start messing with the boost number, which causes blowby at the rings.

Most of ivapor that causes carbon in this GDI engine is re-burnt in the cylinders. What ends up on the intake valves, is minimal. Now the old VT Gamma motors, not so much. They were dirty little buggers.:wink:

Precautionary, maybe but I'd spend my money elsewhere, unless of course you're into "catch can porn":grin:

 

[avayswavay]

I'm surprised they can't invent a coating on intake valves and intake runners that prevents carbon buildup. Maybe that As Seen On TV Red Copper junk. With only 20 easy payments of 299.95, you can get a MAGIC INTAKE! I mean, if cheese doesnt even burn and stick to it, nothing will.

Exactly ! Gaurentee the automakers are just being cheap. For example the euro spec GTI gets Direct Injection and port injection to clean the valves , better fuel control , power etc. In the American market? They know nobody is gonna keep their cars over 3 years so they could care less - hence intense carbon buildup.

 

[avayswavay]

So correct me if I am wrong; what you are saying is that I can avoid this problem by caneing the car as hard as possible in every single scenario like a hungry jockey on an aged horse?

Run it hard, yes absolutely and avoid stop and go short traffic runs. Catch can no, not really. There is such a small amount of fuel dilution in the oil, with this engine, it's not really necessary. You won't see more, until you start messing with the boost number, which causes blowby at the rings.

Most of ivapor that causes carbon in this GDI engine is re-burnt in the cylinders. What ends up on the intake valves, is minimal. Now the old VT Gamma motors, not so much. They were dirty little buggers.

Precautionary, maybe but I'd spend my money elsewhere, unless of course you're into "catch can porn"

Do we have any evidence to back this up on these Veloster N Theta 2 engines? Everyone told me the same on the old VW forums- this engine burns off everything we don't need to take any extra steps. Then of course at 60k carbon raided everything in the engine 😂. I know it's not the same platform ... But I'll take my chances being pre cautionary. But that's just me. There's alot of evidence on the web that EVERY GDI engine will get carbon buildup, especially turbo applications . Folks don't want to do the extra maintenance so they ignore it. I would love to see some data that Hyundai has developed a pcv system to eliminate this issue. I'm pretty sure it's a very similar pcv setup they've used for a decade or so. I would love to be wrong . Please correct me 😂😂. See attachment of old intake valves on 16' GTI w/ 60K miles after 3 years. Beware 😂😂

 

[RedVN]

Honda, VW and even the most all the Hyundai first Gen Gamma and 2.0 Theta engines are terrible with regards to oil dilution. Most are above 3.0-4.00 ppm. Honda's still having trouble with recalls today. I wouldn't own a Honda, even the Type-R. It's going to turn into a nightmare for most owners

The Theta II engine is around 1% fuel dilution in lab oil testing. This is considered a trace amount. I know of one VN/PP which has a catch can and after 15 km he had between 75 and 100 mls in his, running a tuner, intake, downpipe. I've also seen first hand reports from others as well that are the same. Don't know what the engine will be like at 40K. No one know yet. However indications say it doesn't warrant catch can use. until you start playing with higher boost pressure. I'm talking 25 psi +.

I'm not saying, don't run one if you desire. Just be aware of the can/s, do regular maintenance with them. Make darn sure they're serviced regularly and all connection check regularly.

Most of what your picturing on the VW can be chemically cleaned. Doesn't have to be walnut shell blasted. I understand about GDI's in general but the 2.0 Theta II VN engine, is pretty tight and not prone to the same problems.

 

[avayswavay]

So correct me if I am wrong; what you are saying is that I can avoid this problem by caneing the car as hard as possible in every single scenario like a hungry jockey on an aged horse?

Run it hard, yes absolutely and avoid stop and go short traffic runs. Catch can no, not really. There is such a small amount of fuel dilution in the oil, with this engine, it's not really necessary. You won't see more, until you start messing with the boost number, which causes blowby at the rings.

Most of ivapor that causes carbon in this GDI engine is re-burnt in the cylinders. What ends up on the intake valves, is minimal. Now the old VT Gamma motors, not so much. They were dirty little buggers.

Precautionary, maybe but I'd spend my money elsewhere, unless of course you're into "catch can porn"

Here's some great info for anyone whose interested in why all GDI cars will eventually have carbon buildup issues. It's not a matter of the manufacturer or specific engine it's the technology itself . The only way around it is vent to atmosphere or port injection . Carbon buildup usually becomes an issue at 30k-60k. And even with a catch can it only slows down the buildup. You can skip to 6:40 where he starts speaking on the issues of direct Injection. Video has sources as well.

https://m.youtube.com/watch?v=xrLNDgrIw3U&t=143s

 

[avayswavay]

Honda, VW and even the most all the Hyundai first Gen Gamma and 2.0 Theta engines are terrible with regards to oil dilution. Most are above 3.0-4.00 ppm. Honda's still having trouble with recalls today. I wouldn't own a Honda, even the Type-R. It's going to turn into a nightmare for most owners

The Theta II engine is around 1% fuel dilution in lab oil testing. This is considered a trace amount. I know of one VN/PP which has a catch can and after 15 km he had between 75 and 100 mls in his, running a tuner, intake, downpipe. I've also seen first hand reports from others as well that are the same. Don't know what the engine will be like at 40K. No one know yet. However indications say it doesn't warrant catch can use. until you start playing with higher boost pressure. I'm talking 25 psi +.

I'm not saying, don't run one if you desire. Just be aware of the can/s, do regular maintenance with them. Make darn sure they're serviced regularly and all connection check regularly.

Most of what your picturing on the VW can be chemically cleaned. Doesn't have to be walnut shell blasted. I understand about GDI's in general but the 2.0 Theta II VN engine, is pretty tight and not prone to the same problems.

I think this issue is really relevant to owners who plan to keep the car for a long time . If your only gonna get to 40k-60k and trade the car in I would agree don't worry about it. But if blow by will occur , and carry oil vapor back over the valves . Then eventually , eventually you will get carbon buildup . There's simply no way around it . Some engines are better than others but the end result is the same . I've had countless convos with the same reasoning in regard to the VW. And I have first hand experience that they were simply false. But again I would love to do the testing on my own motor. Also thanks for the figures this is good information. As I'm new to the Hyundai family I simply don't know, but does anyone know how the theta 2's did on the Genesis coup after 40k+ miles in regards to carbon buildup?

 

[avayswavay]

Honda, VW and even the most all the Hyundai first Gen Gamma and 2.0 Theta engines are terrible with regards to oil dilution. Most are above 3.0-4.00 ppm. Honda's still having trouble with recalls today. I wouldn't own a Honda, even the Type-R. It's going to turn into a nightmare for most owners

The Theta II engine is around 1% fuel dilution in lab oil testing. This is considered a trace amount. I know of one VN/PP which has a catch can and after 15 km he had between 75 and 100 mls in his, running a tuner, intake, downpipe. I've also seen first hand reports from others as well that are the same. Don't know what the engine will be like at 40K. No one know yet. However indications say it doesn't warrant catch can use. until you start playing with higher boost pressure. I'm talking 25 psi +.

I'm not saying, don't run one if you desire. Just be aware of the can/s, do regular maintenance with them. Make darn sure they're serviced regularly and all connection check regularly.

Most of what your picturing on the VW can be chemically cleaned. Doesn't have to be walnut shell blasted. I understand about GDI's in general but the 2.0 Theta II VN engine, is pretty tight and not prone to the same problems.

Also I forgot to add the VW MK7's had 1% and less oil dilution in laboratory testing as well which you are correct is considered a trace amount. I heard the same exact line of reasoning in regards to the GTI. Hence why I didn't take steps until about 60K and at that time it was completely coated in carbon even with low oil dilution.

 

[TNcoupe]

I ran a catch can on my Focus ST for 66,000mi and emptied considerable amounts of oil out of the catch can every oil change. Did an oil sample and Blackstone said <1% fuel dilution in the oil. They work...do we need them, possibly but who keeps a car that long anyways.

 

[avayswavay]

I ran a catch can on my Focus ST for 66,000mi and emptied considerable amounts of oil out of the catch can every oil change. Did an oil sample and Blackstone said <1% fuel dilution in the oil. They work...do we need them, possibly but who keeps a car that long anyways.

**Raises hand slowly.** Haha yea this is what I believe is the fundamental argument about cans. The data says they work , the data says that eventually you will get carbon buildup as long as you have blow by. Some simply can't be bothered with the extra maintenance bc they won't keep the car that long anyway . And there's nothing wrong with that , to each his own. I myself personally try to keep cars over 100k and the N will be no different.

 

[DarkHorse]

I ran a catch can on my Focus ST for 66,000mi and emptied considerable amounts of oil out of the catch can every oil change. Did an oil sample and Blackstone said <1% fuel dilution in the oil. They work...do we need them, possibly but who keeps a car that long anyways.

**Raises hand slowly.** Haha yea this is what I believe is the fundamental argument about cans. The data says they work , the data says that eventually you will get carbon buildup as long as you have blow by. Some simply can't be bothered with the extra maintenance bc they won't keep the car that long anyway . And there's nothing wrong with that , to each his own. I myself personally try to keep cars over 100k and the N will be no different.

I’m in the same boat.

I put 100k on my VT in 4 years using it as my daily driver, and I just got the N to replace it. I ran a catch can on the VT and I absolutely intend to do the same with the N. Better safe than sorry...

And my compliments to the OP... That is a much cleaner catch can install that I was ever able to achieve with mine, lol! Looks great!

 

[avayswavay]

I’m in the same boat.

I put 100k on my VT in 4 years using it as my daily driver, and I just got the N to replace it. I ran a catch can on the VT and I absolutely intend to do the same with the N. Better safe than sorry...

And my compliments to the OP... That is a much cleaner catch can install that I was ever able to achieve with mine, lol! Looks great!

Haha thank you very much! I am a tad worried about the elevation of the can in relation to the valve cover but hoping the height is negligible. This seemed to be the best open place to mount the can. Might also shorten the lengths of the tubes as well if I'm not too lazy we shall see! Also, how were the carbon buildup issues on the VT? Did you ever have to have the valves cleaned?

 

[avayswavay]

Okay, guys did some more digging and research on this platform in relation to carbon issues. While it is a fact that at some point these cars will experience carbon buildup because they are T-GDI's there seems to be another discussion taking place in the community on the most effective ways to actually catch the oily vapor re-circulating back over our valves.

Alternatively, I've seen some owners of old VT's and VN's running VTA setups on both the breather side and pcv side. Some are even running a third breather cap. I can't recommend this as I don't have enough experience venting a pcv side to the atmosphere. I was always under the impression that the ECU was tuned for the pcv side being in vacuum when the engine is not under boost, thus always drawing out oily vapors when the car is not under boost. Individuals claim they have had a lot of success running this setup but I do not have any personal first-hand accounts. I was also under the impression that without vacuum, blow-by will accumulate in the engine until enough blow-by pressure is generated to force oily vapors out of breathers that are VTA. To me, this seems like it would cause a lot of back-pressure and loss of performance under normal driving conditions. However, others have claimed the opposite effect and I would love to see any dyno results under normal driving conditions (when vacuum would normally occur). Furthermore, one will fail emissions (in the USA at least) while VTA and your gonna have oil all in the engine bay and oil smells within the cabin.

So moving on to another closed system set up, individuals have suggested using catch can on breather side instead of pcv side. I would agree with this suggestion if one is always under boost/races/tracks the car. Because I don't track and just do spirited daily driving my car is normally not under boost and normally under vacuum. This means most of my oily vapors are being drawn out of the pcv side (probably like 90% of the time), thus why my catch can is on the pcv side. I suppose a dual can setup is also another solution however some have reservations about restrictive airflow.

Finally, I talked to a gentleman in South Korea who heavily races his VN and he has seen an IMMENSE amount of carbon build up on his pistons and intake valves. He has about 10k miles on his vehicle so we can forget about these cars dealing with this carbon issue on their own. This is simply not the case for any car manufacturer unless you are VTA or running multi-port fuel injection. He is now running methanal to combat carbon buildup. So we do not have to wait until 40k or 60k to see what these engines will look like. He races his engine so more blow by , more oily vapors going through the breather tube so you get the idea. It has increased the amount of carbon buildup. So maybe his engine more so simulated 20k or 30k of normal driving (you get the idea). Also, I realize I didn't post this in the engine discussion section so eventually ill just move it over. My intention is to share as much good info as possible and help people keep their beloved VN's in the best driving conditions. If you are going to trade it in at 20k. None of this applies to you haha. See attached images for evidence of carbon builduip. You will have to zoom... but ladies and gentlemen its there.

 

[RedVN]

Also I forgot to add the VW MK7's had 1% and less oil dilution in laboratory testing as well which you are correct is considered a trace amount. I heard the same exact line of reasoning in regards to the GTI. Hence why I didn't take steps until about 60K and at that time it was completely coated in carbon even with low oil dilution.

You'll always have to do the intake valve maintenance with a GDI, especially after running it for 50K miles.

Chemical cleaning is a must, if you want to keep it in good nick and plan to run it over 70K+. I'd suggest, you utilize Chevron Techron (Total Fuel Cleaner) every other tank full. You can utilize the BG Cleaner and their intake and valve service every 15K. It will remove nearly all the build up and keep it clean. It cost a little but if you're going to keep it thru the 100K warranty, worth it IMO. we'll see as the particular engine gets some mile on it.

I'm more concerned with the top of the valves and stems, then the bottom. This is residual, from constant high temp running. You'll see it on most. The type of oil he's running, is more important, than the photos he provided. With some of the shell HP oils and others, we've already seen a fair amount of coking on the turbo impeller stems and seals after a few hard track days.

in these photos, this is what we call coking not carbon build up. It comes from operating high temps and not poor oil viscosity. A lot of engine heat breaks down oil viscosity and causes this type of residue as it's not being washed off.

The problem with a GDI is; the fumes and carbon as a result have nothing to wash over the intake valves. Higher temps, higher on boost use and blowby cause oil dilution from unburnt fuel passing the ring and being circulated into the oil pan. It's just then norm with GDI's some worse then others. GDI have been on the road for over 2 decades +. There are still a lot of them as well. There's been no recalls on them, for this issue.

It's an automotive engineers cheap solution of producing engines and meeting emission requirements. Multi-port is GDI's are the way to go but be ready for a price increase in the vehicles that utilize then. It's a balancing act for manufacturers. My IMPO not a good on either. It leaves the owners, with higher maintenance cost long term.

 

[avayswavay]

Also I forgot to add the VW MK7's had 1% and less oil dilution in laboratory testing as well which you are correct is considered a trace amount. I heard the same exact line of reasoning in regards to the GTI. Hence why I didn't take steps until about 60K and at that time it was completely coated in carbon even with low oil dilution.

You'll always have to do the intake valve maintenance with a GDI, especially after running it for 50K miles.

Chemical cleaning is a must, if you want to keep it in good nick and plan to run it over 70K+. I'd suggest, you utilize Chevron Techron (Total Fuel Cleaner) every other tank full. You can utilize the BG Cleaner and their intake and valve service every 15K. It will remove nearly all the build up and keep it clean. It cost a little but if you're going to keep it thru the 100K warranty, worth it IMO. we'll see as the particular engine gets some mile on it.

I'm more concerned with the top of the valves and stems, then the bottom. This is residual, from constant high temp running. You'll see it on most. The type of oil he's running, is more important, than the photos he provided. With some of the shell HP oils and others, we've already seen a fair amount of coking on the turbo impeller stems and seals after a few hard track days.

in these photos, this is what we call coking not carbon build up. It comes from operating high temps and not poor oil viscosity. A lot of engine heat breaks down oil viscosity and causes this type of residue as it's not being washed off.

The problem with a GDI is; the fumes and carbon as a result have nothing to wash over the intake valves. Higher temps, higher on boost use and blowby cause oil dilution from unburnt fuel passing the ring and being circulated into the oil pan. It's just then norm with GDI's some worse then others. GDI have been on the road for over 2 decades +. There are still a lot of them as well. There's been no recalls on them, for this issue.

It's an automotive engineers cheap solution of producing engines and meeting emission requirements. Multi-port is GDI's are the way to go but be ready for a price increase in the vehicles that utilize then. It's a balancing act for manufacturers. My IMPO not a good on either. It leaves the owners, with higher maintenance cost long term.

What oil are you personally running right now if I may ask ? I've heard some bad things about Quaker State which I guess is what comes in the motor from factory. Also in your experience I guess that using a fuel cleaner this often has no adverse side effects in regards to the injectors ? I do agree at some point your just gonna have to clean the valves and yup I agree that the current pcv systems are just a cheap way to meet emissions. Maybe one day they will also find a cheap system that does the job better lol. Thanks for the input , good info.