Quote:
Originally Posted by Helix13mini
I wanted to throw a shout out to Czar, who made a believer out of me with his explanation of hard driving's effect on carbon build-up.

Those of us who also own ALFAs like to call it an Italian tune-up.

 

Hi,

Out of interest I recently had reason to pull the head off my JCW rally car. This car has done 15,000kms (10,000 miles) of extremely hard racing and rallying. Around half the life of the engine would have been under extreme conditions, ie full throttle, high revs and high boost.

The car is an N14 engine, and is running the standard setup ie no catch can, stock recirculation, no meth injection etc

I had a good look at the the valves when the head was off. There was zero carbon deposits, absolutely 100% clean.

This tends to support Czar's theory.

Robbo

 

I was thinking about getting an OCC. This thread has convinced me that there is no need.

Good explanation Czar.......

Money better spent elsewhere.

Maybe I'll add the $200.00 to a fund for some light weight Enkie wheels and Falken RT 615K's

 

Feb 1, 2012 @ 73,416 miles
I had my first walnut blasting service done due to excessive carbon buildup and frequent superknock faults when driving. I drove the car 120 miles back home, removed the PCV hose and blocked its ports, and put a catch can on right away.

Mar 22, 2013 @ 89,263 miles
I had my second walnut blasting service done due to excessive carbon buildup and frequent superknock faults when driving. Here's what my valves looked like:



Needless to say, the catch can did f--k all for my car. I removed it straight away and have accepted that annual cleanings will just have to be factored into the cost of ownership. Thank god my car payment goes away in a year; makes it a little easier to afford.

 

Wow! First piece of real data. Confirms my decision to water inject,...AND...drive the hell out of the car. Thanks Fishbert.

 

Woah there… let's not get carried away here. It "confirms" nothing more than a catch can did jack squat on my car.

Water/meth injection doesn't do much, either, according to BSH Speedshop.

Here: "We love methanol injection over here however the cleaning affects of the injection process are mostly seen in the combustion chamber. From all the DI manifolds I have pulled from cars with meth injection I cant say I have ever seen anything on the intake side that really said "wow this is the ticket""

and here: "My aim was very much to say that methanol is an excellent way to make clean power but is not the solution for carbon buildup on the intake valves that it is often made out to be."

As for driving the hell out of it… there are some nice-sounding anecdotes in here, but I'd still keep a very close eye on things.

 

This is on an N18?

How much did the walnut blasting set you back each time?

 

N14.
$500-600(?) at the dealership. (a little less than 1 car payment)
They normally change the spark plugs as part of the walnut blasting service, but since it was only a year since my last one, I told them to skip it this time around. That made it a little cheaper.

 

so fishbert has an N14 ... he has provided no data about N18 buildup, only clouded the issue

scott

 

I'm sorry, I thought this was a discussion of whether catch cans did much of anything to prevent carbon buildup.

OP, can you help out here?

That's what I thought...

 

the N14 and N18 PCV systems are very different, whether an OCC works on an N14 would mean little on an N18

scott

 

First...
If one can show evidence that a catch can doesn't "work" (overly nebulous/vague usage, but I'll play ball) in a seemingly ideal application such as the N14, then that could mean quite a lot when thinking of extending the idea to a much less-than-ideal application such as the N18. I would argue that this is the value of my comment and pictures.

Second...
While it's exceedingly obvious that you are an expert on the N14 vs N18 PCV system designs , please do me a favor: Go search for PCV-related discussions on these forums from back when the N18 engine was a brand new bird. That is a little before your time on these boards, so I get that you may not be familiar, but I think you'll find that I was right there in the middle of most of it. So, trust me when I say that I don't need you to relay overly vague generalities about N14 vs N18 PCV systems to me, Mr Smartypants man.

 

I know they work quite decently to decrease the situation on the n14 but the n18 doesn't need a catch can.

 

What are you talking about, Scott's right...the design is different so the statement is irrelevant. No one has N18 data to show with and without an OCC

 

*sigh* ... Go back and review post #85. Everything else has been bmwr606 trying to play forum police.

Data of what? Carbon buildup on intake valves?

You can't put a catch can inbetween the crankcase and intake ports on an N18 engine, so your "N18 with an OCC" state is about 95% bonkers with respect to intake port carbon buildup. The best you can do is put one inbetween the crank case and the CAI intake boot, but that's -by far- the lesser of the two contributors in the PCV system, as it's only really expelling crankcase vapors under boost conditions and then it has to work its way through the turbo and intercooler (which would behave like a giant catch can itself) before ever seeing the intake ports. And that's -if- catch cans did much of anything in the first place ... which goes directly back to what I was showing in my first post (that bmwr606, in his great wisdom, didn't approve of).

But besides that nonsensical "with and without" setup, yeah, people have posted pictures of intake port carbon buildup on N18 engines.
Cases in point: here's one ... and oh yeah, POST #3 IN THIS VERY THREAD!! ... Seriously?! You guys are just drive-by commenters in here, aren't you?

Have you even read the first 3 pages of this thread?!?!
No, it was just the subject line, wasn't it? Figures.

 

Okay let's get this out of the way, everyone should or does know no matter what the N18 will get carbon buildup eventually whether it be little or a lot of the valves being covered(depends on driving conditions).

My point, the dealer and I took a look at my valves around 36k miles. Nothing was found but what the guy who took his car to Clint looked like. I barely even call that carbon buildup, that's nothing compared to what the N14 looked like when it had fully covered valves. No one is disputing that...but why waste $170 on a catch can, when I can spend it on other mods for the car or other hobbies. Get your walnut blasting done at 70-80k miles, and be done with it.

 

... especially when it's on the 'wrong' PCV line (because that's all we can get at) and cans don't catch much anyway.

 

Well I guess you aren't gonna let it go?


People will either believe in those catch cans religiously, or won't buy them(I'm in this category). I keep checking my valves every 30k miles. So when I find a HUGE chunk of mess in there, I will post pictures, until then I will keep on moving with out it til I get around 80k for my walnut blasting.

Obviously the N18's have been designed a little better so we don't need to buy it, because your never going to stop preventing the issue of carbon on your valves guys. Prove me otherwise, and I will shut up.

 

It's frustrating to see your snark about "let it go" followed so closely by a statement that perpetuates some of the same misinformation. But yeah, I'll "let it go" after clearing that up.

It's not that the N18 is designed better so we don't need to buy a catch can ... it's that the N18 is designed in such a way that a catch can is impossible to put where it would matter most. That the N18 appears to collect carbon at a slower rate is a really good sign, but not because N18 owners would need to buy catch cans otherwise ... it's because if it was heavier buildup, N18 owners would be completely screwed.

There; letting it go. This thread's gone off the rails enough with the drive-by forum police and me trying to defend my comment showing a popular oil catch can being generally worthless at catching oil.

 

Yes, the main reason was for me to decide whether or not to install an OCC, but I have an N18. I wasn't trying to determine if the OCC did a good job, just if carbon build up is a problem (or as much of one) on the N18. The topic of the thread is carbon build up on the N18.

 

How much oil can a catch can catch if a catch can can catch oil? That is the real question.

 

Time to duct tape my head.

 

None....at least for mine hahaha

 

Two of the members that I talk to frequently, they said "I haven't caught a thing, zip!" So I wish they would post something here for those contemplating the almighty "catch can". Just curious, I'm not going back to read it all, who has a catch can on their N18's here?

 

Moi!