Odd solution about carbon...

[shah269]

So i was at my mechanics having my 5k mile oil change.
Switching out from the BMW jungle juice to the French Elf full synthetic.
And we got to thinking and talking about the carbon and all the other cars are having the issue.

We came to the conclusion that there may be a method by which to slowly over time remove or prevent carbon build up.
By adding a more volatile detergent to the oil which would outgas at a significantly lower temperature than the oil, you could slowly over time introduce a chemical cleaning agent to the the intake manifold and over time wash away some if not all of the accumulated carbon.

We were just having coffee and discussing the issue and such over the counter cleaners such as marvins mystery oil, sea foam, lucas or even good old Chevron Techron added to the oil may do the trick. Though perhaps the best may just be a cup of good old kerosene. A few days right before an oil change may be enough to slowly push back the tide of carbon build up.

Though we were unsure of if just adding it to the oil on a regular basis would have any harm. But when you have a high strung engine that is turbo charged...you tend to tread lightly when it comes to playing god with the oil formulations.

I do have a good friend who is a product manager for Volvo and they will be going 2L turbo DI in their next model year...and he is being very very tight lipped about it but he did let slip that they have been in talks with Mobile 1 about some sort of anti carbon formulation.

So guys i know this sucks, for some of us more than others...but it's industry wide and maybe in the next year or so as more DI engines come on the roads there may be an over the counter additive we can add to our oil to wash away the buildup with out the need of nut blasting our intakes.

Hope this helps.

[int2str]

Not sure I understand?

The top of the intake valves don't come in contact with the oil. So how would adding something to the oil help?

[shah269]

As I and my mechanic and many understand it your PCV produces a partial vacuum in your crank case via your intake. Think of it as a bilge pump.
In theory this means less of that dirty oily air is getting into the air and the penguins in the ocean are not dying...
Well in the good old days we didn't care because any oil that came with that air was washed into your combustion chamber via your injectors...though your manifold did tend to get dirty as all hell and every now and again you did need to spray the thing down....like every 30K miles + if ever!
But now that the injectors are inside the combustion chamber....there is no washing of the intake valves so that oil filled air from your crank case is coming in contact with your hot intake valves and caking them with..oil...which over time cooks and becomes....carbon.
woo hoo thank you DI for the power and the efficiency and for making a mess.

[SteveAZ]

^hahahaha, that was pretty good!

[Fresh Face]

i already solved this issue. Pour a bottle of techtron or whatever anti-carbon liquid into your meth tank. Meth sprays, cleaner cleans, problem solved. A bottle per meth tank should clean that up in no time.

[SteveAZ]

[yawn]

Carbon buildup is an unfortunate occurrence which adds to the maintenance cost of our vehicles. If something simple as you suggest could be had, I'm sure there would be a resounding amen from this community.

[Wibbles]

This would be a better solution:

http://www.terraclean.co.uk/index3.html

Available in the States too I believe.

[yawn]

I dunno about Terraclean. There seems to be alot of 'snake oil' comments about it being thrown around, as opposed to walnut shell blasting which seems to be the tried and tested gold standard.

http://www.e90post.com/forums/showthread.php?t=718641

and

http://www.e90post.com/forums/showthread.php?t=714808

Just a couple of links to some talk about Terraclean over at the 3ers.

[RimasRS]

Think about your Turbos before adding anything to the engine oil...

I think only and best way it is to clean them mechanically every 50 000 kms

[Stohlen]

Originally Posted by wibbles

This would be a better solution:

http://www.terraclean.co.uk/index3.html

Available in the States too I believe.

I dont think i'd buy anything from someone with hair like that

[Ænema]

Depending on the carbon buidup, i could see that as a possibility for helping to prevent Carbon buildup(much like the meth could, but that's been a long debate with no real conclusions either way.)

However, it's not going to remove any carbon that's built up. Once it builds up some of it will begin to harden. The only way to do it is either media(walnut) blasting or a combination of chemical and pressure washing with HOT water.

Also, the source of the carbon has a lot more to do with EGR than PCV.

[Freon]

I would generally avoid experimenting with oil additives on your own or with anyone who did not have graduate education in chemistry. Even then I'd be doing it on a test bench with a test motor. Seems... like a bad idea to take an idea your local mechanic has and try it out on a $10k USD engine. If one of the big players like Mobil1 or Castrol wants to sit down with BMW and come up with an approved oil that does what is described in OP, I'd consider it, but nothing less.

I don't think the N54 or N55 engines have actual an actual "EGR" system, and I doubt backflow of combusted material into the intake ports. I think PCV is more than sufficient to describe what is going on.

[shah269]

Originally Posted by RimasRS

Think about your Turbos before adding anything to the engine oil...

BINGO!
And therein lies the problem that BMW and VW are having!
My mechanic was telling me he was having great success in working with people with non Turbo Audi's and adding Marvin’s Mystery oil / kerosene to their oil 500 miles before their oil change.
As stated since the MM and the kerosene have a lower vapor temperature than the oil they evaporate off as the car heats up.
As this vapor travels through the system it “washes” away some of the carbon slowly into the combustion chambers.
Now remember as I understand it all auto makers are going DI in the next few years to get the fuel economy they need for the not too distant future.
So this will be a major issue! I can’t see a Honda owner dishing out $700+ to have his engine nut blasted.
And remember the carbon is not coming from the gas you are using, it’s coming from the oil burning.

[Ænema]

Originally Posted by Freon

I don't think the N54 or N55 engines have actual an actual "EGR" system, and I doubt backflow of combusted material into the intake ports. I think PCV is more than sufficient to describe what is going on.

It doesn't use a traditional EGR valve style system. It uses VANOS phasing to increase reversion in the intake during overlap to recycle some of the exhaust gasses. PCV is a contributing factor but not the major factor.

Cobb tuning has actually reworked some of the VANOS tables with reducing this effect in mind.

[shah269]

Wait...so where is the carbon comming from?
Per my discussions with my mechanic he is very sure it's from the engine oil and not from combustion

[Ænema]

Originally Posted by shah269

Wait...so where is the carbon comming from?
Per my discussions with my mechanic he is very sure it's from the engine oil and not from combustion

The carbon is coming from combustion. At least, a majority of it is. PCV and what little oil goes past the turbo seals are the other major factors.

[Freon]

edit: double post..

[Freon]

The carbon is coming from combustion. At least, a majority of it is. PCV and what little oil goes past the turbo seals are the other major factors.

What makes you think this?

[brusk]

Terraclean is a good product just won't do anything for direct injection and it's carbon build up problems. And Ed China with the crazy how is in all kinds of British car shows like Wheeler Dealers. As for the techron in the meth tank I wish somebody had the time to take the intake off and then run a techron/meth setup and retake pics like 5K miles later. From what others have said it will keep it from getting worse and clean up some of the softer stuff but that's it. Best things I've hears so far are Cobb Vanos changes, RB PCV valve (mostly cause the factory ones have seen alot of failures), catch can and meth with cleaner. All that and you might be able to avoid recleaning once you get the valves clean.

[Ænema]

Originally Posted by Freon

What makes you think this?

I just have a hard time seeing PCV being the #1 cause when you consider the only time the PCV system is active when at idle or low load. When in in boost or the throttle blade is significantly open the PCV isn't moving oil vapor. Now, I can definitely see it being a factor(especially over LONG periods of time.) Honestly, I see turbo seal seepage playing a larger role.

[Rowdy]

Turbo seal seepage? That makes me chuckle..

Yes the PCV is open under light load(vacuum) and not boost. But The remnants of that oil and sludge doesnt just instantly disappear down through the cylinders. Pull an intercooler off and see the film of oil coating the insides or in your charge pipes! Yuck! You're ingesting that oil throughout the range, just in varying amounts.

The Coopers are notorious for this as well. I'm still certain it's to do with PCV and the lack of any and all particles of fuel through the runners, ports and backs of the valves that is the issue.

I'd like to see some proof otherwise. But in the interim, while the car is new and hasnt seen any buildup, I'm gonna be trying to prevent it with an OCC and a water meth setup!

Someone else chimed in, during a previous thread saying that they didnt see any difference with those two additions. But I'm betting they were made AFTER the buildup and they were not effective in getting rid of the caked on buildup. Time will tell