Is FSI Valve Carbon buildup a valid concern?

[johnw]

I'm asking because, while I haven't seen the valves in my 3.2 FSI engine [and probably never will], there are some pictures of horrible buildups on the web for other FSI engine (due to no fuel cleaning the valve and oil from PCV etc etc).

Just wondering if people here think it's a valid concern because since fuel is directly injected, then the only effect of the carbon build up would be restricting airflow and it'll take ALOT of buildup to start causing significant restriction.

Has anyone has done anything to prevent/clean the supposed carbon buildup in FSI engine? I plan on installing a catch can between the oil separator and the manifold as when I pull the PCV out, it's quite oily inside (indicating that the oil is not getting separated that well)

Also, has anyone tried the upper cylinder cleaner stuff from Subaru in the FSI engines? (I've used it on my 1.8T and it's mint, but not sure about the FSI)

[johnw]

Guess its not a valid concern from the general response

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[Greg Roles]

I would have commented, but it looks like I'm trying to hard sell my cans! Any decent can will indeed help, but you may need to do a bit of tinkering to make up the perfect system for the 3.2. There are great solutions out for the 2.0 FSI, and the parts are available individually, need to see some pics of your engine with the cover off to work it out.

[johnw]

Oh I didn't know you sell cans
I do wan to put a can in, the first thing I did when I got my 1.8T is to put in a Saikuo Michi can.

Well I know that I need a can with 24mm in and 21mm out to fit to the 3.2

The 3.2 seems simpler as theres only one port for pcv unlike the 1.8t where theres a crank case one too.

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[whiteVR6]

Seb has been doing a lot of work in regards to the carbon build up issues with FSI cars. It is an issue once the cars reach higher kms and causes all sorts of problems with PCV systems. Catch cans dont work in the long run and cause internal issues with the rocker cover itself. It seems to be a fairly complex system compared to the multi point injection on earlier cars.

[johnw]

mmmm ok, my car's got 88K on it already. Guess I'll just have to wait till [if] it throws a CEL and rip the head off to clean/replace the valves then? :S

From looking at it, it does look hard to put in a catch can without messing up the factory system, especially trying to fit 20mm piping there.

[Greg Roles]

Seb has been doing a lot of work in regards to the carbon build up issues with FSI cars. It is an issue once the cars reach higher kms and causes all sorts of problems with PCV systems. Catch cans dont work in the long run and cause internal issues with the rocker cover itself. It seems to be a fairly complex system compared to the multi point injection on earlier cars.

...and all major aftermarket manufacturers such as Forge and 42DD are prototyping even better solutions for the petrol FSI's, I can only speak for 42DD, but it's close to production. A can is a LOT better than stock. Most definately something to do on the diesels!