jbx2

Anyone running a catch can on a Base Macan?

chassis

Maybe the Tiguan, A4, A5 or Q5 folks would have info. Much higher production volume on those models.

VAGfan

I don't think many people are running catch cans on this engine. They used to me more popular, when people thought they might eliminate intake valve carbon deposits, but that theory has not been proved. Also, the PCV oil separation system on the Gen-3 and Gen-4 EA888 2.0 engine has been improved since the original Gen-1/Gen-2 version of this engine. I ran a catch can on my 2010 and 2012 Gen-1 2.0, and yes, it caught some oil, but I don't think it had a significant impact to intake valve carbon build-up. They can't hurt, but the benefit is dubious.

Looking at the VW GTI forums is probably the best place to look to see what they are doing.

steveo17

I wouldn't bother. As others have mentioned, the "gains" might be minimal at best. The maintenance of having to empty it then too is just a no thanks, not to mention the risk of freezing if not maintained properly as well. I had one on my 2006 MKV GTI and would never run one again. I believe it froze after the car was outside for a week without running. I drove the car home not thinking anything of it and then within a week or so I had blown the turbo on my car likely due to oil starvation.

chassis

Interesting. If a catch can does not reduce intake valve deposits then the root cause for deposits is from fuel injected into the cylinder.

VAGfan

No, the root cause is oil on the backside of the intake valves that gets baked-on there during the periods of EGR (exhaust gas recirculation). EGR is a must-do engine control strategy to meet NOx emission requirements. EGR is implemented by having lots of valve (intake & exhaust) overlap, which allows some hot exhaust gas to be pushed into the intake manifold, and then pulled back into the cylinder in the beginning of the intake stroke. That's done with the variable camshaft timing controls. Auto manufacturers do it this way as it eliminates a separate EGR valve. The oil comes from two places, 1) thru the PCV system (where a catch-can can help reduce), and 2) through oil seepage down the valve guides (some oil is purposely allowed to go down the valve guides to lubricate them).

Oddly, as the cause for the deposits are high temperatures of the intake valves, even higher intake valve temperatures reduce these deposits...that's why engines operated for some extended high-speed highway driving typically have lower incidences of issues due to carbon deposits on the intake valves.

As it is direct injected into the cylinder, after the intake valve, gasoline (or any additives) has little to no effect on carbon deposits on the back of the intake valves.

Nickshu

I thought the more recent versions of the E888 engine have two injectors now, one direct and one spraying on the back of the intake valve, which has eliminated the issues of carbon building on the earlier engines? Maybe I am incorrect but I thought that was the case.

VAGfan

Some EA888 engines, typically for stricter Euro emissions market, have the dual injection system, but the USA 2.0 EA888 typically don't have that. The Macan 2.0 certainly does not have that.

jbx2

Thanks everyone for the replies. I'm troubleshooting a brief smoke cloud on warm start after sitting. I guess I'll pull the PCV valve and check the diaphragm. It's a 2018 2.0 with 65K miles a Cobb 91 octane tune for the past 40K

chassis

Thanks. Do all Porsche V-engines use EGR? EA888, EA839, EA825?

VAGfan

Pretty much all engines use EGR to meet emission standards.

chassis

Thanks. Can you point to (link with image) the EGR valve on an EA839?

VAGfan

Almost all engines use variable valve timing to implement EGR, so an old-school EGR valve is not used.
The EA839 has variable valve timing, both the intake and exhaust camshafts.

chassis

So exhaust gas is backwashed into the intake manifold on the exhaust stroke?

VAGfan

yes
The intake valve is opened early, near the top of the exhaust stroke, which pushes a small amount of exhaust gas into the intake manifold.