Valves- carboning up

[RI_RS4]

as I previously pointed out, there is no way deposits cause a 10% loss in volumetric efficiency, and that is the only way a 10% loss torque can be realized since displacement and compression remain the same (as does the number '4' and Pi~3.141596....)

Arthur,

If the deposits cause timing retardation as a byproduct, then the Brake Mean Effective Pressure (BMEP) is reduced. Your calculation is an overly simplistic first order approximation, which assumes that all other factors are unchanged, that intake valve and combustion chamber deposits do not cause increased detonation due to pre-ignition or turbulent flow pattern disruption. 10 degree ignition timing change can easily cause a 5 to 10% change in BMEP, which linearly translates to torque reduction.

Timing advance increases NOx emissions. Timing <beep> does not have a significant impact on emissions. RS4 owners have logged significant timing pull due to IVD.

[RI_RS4]

Arthur

If you are referring to US Patent #6866031, then I've posted the link to it in on other sites. I did not just "disingenuously" post part of it. From the time I first posted on this, I provided a link to the full patent. I obtained knowledge of this patent from an engineer inside Audi US who wishes to remain anonymous.

The invention claim is one of a catalytic surface on the intake valves to counteract formation of carbon deposits. My contact tells me that this invention was not implemented in the RS4 engine.

did I say you? but, hmmmmm

the patent covered many things, also exhaust gas recirc and the flaps
and I have conversed with Audi recently and they state that the patent methods were implemented...
and that the engine does run in a stratified (compression injection) mode
hence the need for the very high fuel pressure
otherwise, if only homogeneous, 60-70 psi would be sufficient

I emailed them 2 weeks ago, in response to a post on here...they have been very helpful and have actually visited the site...they also thanked me for pointing out some of the misinformation being propogated and I assume are exploring their legal and PR options...it's defamation to say they know there is a problem, over-rated their engines and are decietful...the internet is unforgiving and does not go away...

as far as the patent, no 'insider' black ops here, it's one of the first googles that come up... it is also public domain information, hence the filing

and if your are saying an Audi employee 'slipped' you confidential data in contravention of his legal agreements (IP, confidentially, etc.), that is not smart posting it...

Nothing confidential was slipped. However whoever you spoke to was woefully misinformed. The US engine does not run in stratified mode, and you should know this. You will easily see this if you perform a Vagcom log. The mode was pulled in the US prior to introduction, due to high sulfur content in the US fuel supply.

[RI_RS4]

the patent covered many things, also exhaust gas recirc and the flaps
a

Actually the patent covers those things as prior art. The only invention claim made in the patent is one of specific catalytic surface coatings on the intake valves.

[ArthurPE]

can anyone guess what the problem with 2many's car was?

I would look at the intake inlet flaps...it looks normal below ~6000

the dyno might not have been set right, the ramp up appears to be too long, this determines the load the engine must supply, it looks like it may have satisified it at ~260 HP or so

the HP is dead flat from ~6300 to redline (`8200)
since P ~ engine speed it must increase (P = T x w, w =2 x Pi x rev/sec)
something is limiting it:
the dyno
engine controls, traction/stability, airflow/fuel/timing

valves with 2-3 mm of deposits may not even cause measurable loss, at most a few HP, you are down ~60 at 7500 or so...

the limiting restriction (or pressure loss which causes volume loss during filling, which in turn is the mechanism for power (loss)) of airflow is not the annulus/torus formed by the valve opening, it is the circlular valve seat opening...deposits have almost no impact, and even less in a DI engine since they do not absorb fuel...

[2manytoys]

Dont get too excited with your carbn buildup denial Arthur. It's all unrelated. The initial problem was carbon. It was fixed, then about two months later a vacuum leak was found (engine and EPC light came on). It's inside the actuator under the manifold. Ironically the Audi dealer removed the manifold to test the actuator and said "wow, look at that" pointing to the carbon, "that's not good, we'll replace the cyclonic seperator because it's come back so quickly" (and yes, I noticed the power dropping away before the actuator problem).

Back in your carbon denial box now sir

Mal

[ArthurPE]

the oil on the valves is not from the blow-back or cyclone...that has been proven
someone disconnected theirs and vented to atm when they cleaned their valves and the valves were smothered again in 2k miles...
my 'guesstimate'...valve seals...

another fellow put a catch can on...it caught a bunch of water, and hardly any oil...and the water would actually help...steam clean the valves...
and it was before the cyclone, so the cyclone would have caught most of the minute quantity of oil anyways...

and I maintain those flaps were your issue since day one...

[2manytoys]

I'm sure you will stick to your story, imagine how embarrasing it would be if you had to start living on planet earth like the rest of us.

[P_G]

Dont get too excited with your carbn buildup denial Arthur. It's all unrelated. The initial problem was carbon. It was fixed, then about two months later a vacuum leak was found (engine and EPC light came on). It's inside the actuator under the manifold. Ironically the Audi dealer removed the manifold to test the actuator and said "wow, look at that" pointing to the carbon, "that's not good, we'll replace the cyclonic seperator because it's come back so quickly" (and yes, I noticed the power dropping away before the actuator problem).

Back in your carbon denial box now sir

Mal

I would be questioning your garage Mal rather than Arthur because all FSI / GDI engines have carbon build up with use; if they were surprised to see it as you suggest then perhaps they haven't opened up too many FSI engines? And like also said, people have used catch tanks and blocked separators and yet carbonisation continues.

[ArthurPE]

I'm sure you will stick to your story, imagine how embarrasing it would be if you had to start living on planet earth like the rest of us.

it's comments like this that make this place less enjoyable...

and it's folks like P_G that make it worth putting up with your crap

I said from the beginning, flaps or something, but definitely NOT deposits...
the dyno curve supports this...
if you want to make it personal, feel free, me I'll stick to the technical merits of the discussion...

[HYFR]

it's comments like this that make this place less enjoyable...

+1

[PetrolDave]

it's comments like this that make this place less enjoyable...

+2

[Sims]

it's comments like this that make this place less enjoyable...

+2

So you guys agree that no-one should be using words like:

"whore, choads (dick), loser, whiner etc " .

[Terry1948]

I thought this thread was to be more civilized and the old one was buried please dont stir up the old one.

[HYFR]

So you guys agree that no-one should be using words like:

"whore, choads (dick), loser, whiner etc " .

+1

[Sims]

So you guys agree that no-one should be using words like:

"whore, choads (dick), loser, whiner etc " .

+1

Thank you for your support on that. You know who the culprit is, and I do hope he will no longer indulge in that practice and that we can share the vast knowledge/experience of all on this forum.