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Without/With Catch Can (Atmo) Comparison Pictures + Discussion

staulkor

V-Dubber
Location
Tempe, Arizona
Ride
VW GTI MkV Fahrenhei
You know of the intake valve issue that plagues our engines. I have some pretty good comparison pictures of what an atmospheric catch can actually does. To my knowledge, there havent been pictures taken of one's car with, and then without, a catch can with a good amount of mileage in between while keeping the same engine mods.

Below is a set of comparison pictures. On the left are my valves from 0 to 50,000 miles without a catch can (I got a catch can at maybe 45k, but the damage had already been done, so I am ignoring this). On the right are my valves from 50,000 to 87780 miles with a BSH atmospheric catch can.

















Note: For 50-80k, there was less carbon on the valves than from 0-50k.
Note: Both scenarios had considerable build up on the walls.

You must remember, the pictures with the catch can only span 38,000 miles instead of 50,000 miles. This means there will be less build up regardless of what modifications are in place to alleviate blow by build-up, so take this into consideration.

Also, please note that since this is an atmospheric catch can, I am assuming it is a perfect catch can; meaning that ALL blow by goes out of the engine and is not consumed. This is in comparison to a recirculating catch can where most, but not all blow by gets filtered. Recirculating systems are not a perfect system and there will be a small amount that goes back in the engine and is consumed. With that being said, I consider this comparison a best case scenario in terms of the least amount of blow by possible.

With that said, this is what I conclude from the comparison pictures:

Catch cans work, but I don't think they work as well as we have been lead to believe. They are effective, but only so much. The pictures show there is still a major carbon issue, and this will NOT magically fix your issues. It may delay when the issues start occurring by a few thousand or even tens of thousands of miles, but who knows.

The catch can did more than I was expecting. I thought the catch can would have done next to nothing, but that clearly isn't the case. It did prevent some carbon build up, however much that may be, but the buildup that did collect and the amount of carbon is considerable.

I believe catch cans have a place for the FSI. They work as advertised, albeit less than you are lead to believe, but they work nonetheless. Please take the pictures into consideration when buying a catch can. Remember that they are no magic cure for carbon buildup. That carbon is a tenacious bastard and take up camp on your valves no matter what you do to prevent it.

ANYWAY, enough with the serious shit and here are some pictures from the job :thumbsup:















Also, that is what you have to deal with having an atmospheric catch can. It is DIIIIRRRTTTYYYY! I degreased everything and the catch can has been removed. I dont consider it worth the mess for the minimal benefits.
 

SpoonGTi

NOM NOM NOM...
Location
Corona, Ca
Ride
what else...
Awesome info man.. but a couple of questions. How come your windshield wiper resovour tube is coated with so much oil? And when did you move to AZ?, I thought you were living in MD with the Capital dubs gang. Plus since your in AZ you going to Wuste?, since your close to Vegas. You should hit it up since it's coming up next month.
 

mrbikle

Go Kart Champion
Location
Hagerstown MD
his bay is covered with oil because he is not using a recirculation kit. with this setup, you will see a lot of smoke and oil crap come out of that open vent.... indirectly coating everything in a thin layer of oil, lol.

If negating a lot of that oil vapor by using an atmospheric vent, imagine how little effect a recirculated kit has... I am taking mine off.
 

stenger944

Gti Guy
Location
Pittsburgh Pa
Ride
09 Mkv GTI
Awesome info man.. but a couple of questions. How come your windshield wiper resovour tube is coated with so much oil? And when did you move to AZ?, I thought you were living in MD with the Capital dubs gang. Plus since your in AZ you going to Wuste?, since your close to Vegas. You should hit it up since it's coming up next month.
The oily mess is a byproduct of a vta catch can....but this is great information and has made me reconsider my previous sense of urgency to buy a catch can.
 

staulkor

V-Dubber
Location
Tempe, Arizona
Ride
VW GTI MkV Fahrenhei
Awesome info man.. but a couple of questions. How come your windshield wiper resovour tube is coated with so much oil? And when did you move to AZ?, I thought you were living in MD with the Capital dubs gang. Plus since your in AZ you going to Wuste?, since your close to Vegas. You should hit it up since it's coming up next month.
All the oil vapor that came out would condense and put a layer of oil on EVERYTHING! Seriously, everything, everywhere, had a lot of oil on it. I had to degrease the entire freakin engine bay to get it all off.

I used to live in MD, but I moved out to AZ for school. Lived here since June last year and never plan on leaving, I love it here.

I would love to go to wuste, but I am not sure if I can make it, but I am trying!
 

bostonaudi

Go Kart Champion
Location
Charleston, SC
Ride
1995 BMW M3
Thanks for posting some data. Given these results, looks like you are nearly as well off using just PCV fix and letting engine burn up crankcase vapor. The deposits look like oil seepage down valve stem that coked up. VTA clearly not appropriate for street cars but good for this test.
 

dustinwark

Miesian
Location
Portland
Ride
'07 VW GTI
That's about what I figured, did something, but definitely did NOT solve the carbon buildup issue. I need to get mine cleaned, 60k+ and no W/M without being cleaned I am sure mine as disgusting.
 

BSH Speedshop

Ready to race!
Location
Speedshop, Az
The concept of a catch can being mainly/solely for prevention of carbon build up is something that is completely exclusive to the D/I platforms. Traditional use has been always been completely different.

As the O/P is running a VTA system, regardless of what anyone wants to say, has almost 0 to do with the PCV system in which a catch can system compliments. The reduction in buildup shows the catch can aided in pro longing it for what its worth, but the real issue is within the design of the cylinder head itself.

The real place for a catch can on a performance minded turbo charged engine is to keep oil vapor out of your combustion chamber and out of your charge pipes/intercooler. The BT guys and highly pushed stock turbo guys will see this on the most major scale.
 

Chris@RT

Banned
Location
ga
Wasn't clarified in the post but when the can went in were the valves cleaned so the comparison is starting from scratch? Or are the pics at ~88K a total accumulation?

I do agree that it appears there may be an issue with the valve stem seals. This is something that i think many are overlooking automatically blaming issues on the PCV/EGR. In many cases valve stem seal issues are masked by the fact that the injectors are washing off the intake valves. The 1.8ts sometimes it can be easy to spot since the center valve will have build up but not the outer two which are washed by the injectors. Also the fact that even stock cars can smoke a bit with no cat installed you don't often get the tell tale blue puffs when the engine is cold like you do on a manifold injection car. It is not an easy job so understandable most are not jumping to do it, but it may eventually be more evident that it is an issue.
 

dustinwark

Miesian
Location
Portland
Ride
'07 VW GTI
Wasn't clarified in the post but when the can went in were the valves cleaned so the comparison is starting from scratch? Or are the pics at ~88K a total accumulation?
IIRC he posted a thread a while back (maybe 38k miles back) were his valves were cleaned
 
Location
Toronto
wat would be interesting now is to have someone compare these valves with someone who did Saaber's DIY and routed recirc back into the exhaust...
 
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