RS4 B7 Stated Power claim of 420ps

[P_G]

Yes my attitude would be and is still the same for the reasons I stated. It is after all a consumable product. We all have freedom of choice; if you don't like the prospect, sell the car and buy something you have confidence will have the power output you believe it should have.

[P_G]

.
How is it that at some point all drivers will experience that their engines get better as they 'loosen up'? .. Could there even be the case that whilst carbonisation does occur that the engine loosening up may even counteract so that the effect is negligible?

Well actually if you expect your engine to get better as it loosens up, and it does not.... it is because there is an engineering problem.

Maybe your well run engine with 396 horses should really be in well excess of 414.

Who says it doesn't, a rolling road? We've done that debate to death so it could well be doing more than 414bhp. I'm not taking the 396 as gospel as the same car under similar conditions on a separate occasion also did 402. Bear in mind that 396bhp and 402bhp were with a vacuum leak so it may well do more.

[SimonC]

the engine will take the same amount of air with or without obstruction...
it's the throttle that limits airflow, nothing else...it is so much larger than the valves it feeds it they have little influence, or in control valve terminology, 'throttling' range...

if the valve orifice x lift were restricted, it is not, because it is much larger than the valve seat opening, but if it were the air velocity will increase and the Q remain the same...
you would have more DP across the valve, but all that needs to happen to offset that is to crack the throttle...

So engines with variable valve lift have this function for what reason? I thought it was to get more air into the cylinder. Honda has had us all fooled for years - all that was required was a bigger throttle!

"Cracking" the throttle is a bit difficult when you've already got it wide open (a prerequisite for maximum power)

This theory that you can overcome a restriction at the intake valves by opening the throttle wider is like telling someone having an asthma attack to open their mouth wider.

I'm mildly impressed by your formulae but if it were that simple then manufacturers wouldn't use race-tracks, mountain passes and wind tunnels to develop cars.

[ArthurPE]

David,

On this thread you will see Arthur writing the same stuff:

http://www.audizine.com/forum/showthrea ... p-Clean-Up

The issue is clearly gaining traction in the US. We are away behind here in the UK.

His best line in that thread is:

I seek no quarter, nor compassion or understanding...you do not exist to me, and vice versa...so save the psych 101 for someone who gives a crap and has a modicum of respect for what you say...you have been sadly mistaken if you think I give a %&^$

Whilst he lays claim to his engineering credentials, he has not taken a single measurement in support of his contentions. About the only thing he has measured is acceleration...using the onboard laptimer and the Mark 1 eyeball.

He glosses over the fact that another poster has found that the times registered by this method and using VAGCOM differ by ~0.5secs. So, the previous thread on this site dealing with acceleration times...you all ought to add 0.5 secs to your times if you've used the onboard lap timer...



But thats not really the point...

You can see US owner after US owner contributing to the aforementioned threads talking about the state of their manifolds, the constant CEL lights, the recovery of hp post cleaning and Arthur still digs his heels in.

Remember, even VAG engineers have written:

Directly from the technical staff of VAG is complete acknowledgment of the FSI intake valve deposit issue, and it's impacts, including: decreased performance, misfires, catalytic converter damage ... etc.

"Gasoline engines with direct injection of the fuel into the combustion chamber, i.e., not into the intake port, suffer especially from the problem of the formation of carbon deposits on components. Carbon deposits form especially in the neck region of intake valves. A more exact analysis of how these carbon deposits form leads to the following result: Oil and fuel constituents first form a sticky coating on the components. These constituents are chiefly long-chain and branched-chain hydrocarbons, i.e., the low-volatility components of oil and fuel. Aromatic compounds adhere especially well. This sticky base coating serves as a base for the deposition of soot particles. This results in a porous surface, in which oil and fuel particles in turn become embedded. This process is a circular process, by which the coating thickness of the carbon deposits continuously increases. Especially in the area of the intake valves, the deposits originate from blowby gases and from internal and external exhaust gas recirculation, and in this process, the blowby gasses and the recirculated exhaust gas come into direct contact with the intake valve."

"Especially in the area of the neck of the intake valves, excessive carbon deposits have extremely negative effects for the following reasons: In the case of Otto direct injectors, the successful ignition of the stratified charge depends to a great extent on the correct development of the internal cylinder flow, which ensures reliable transport of the injected fuel to the spark plug to guarantee reliable ignition at the spark plug. However, a coating of carbon deposits in the neck region of the intake valve may interfere so strongly with the tumble flow that ignition failures may occur there as a result. Under certain circumstances, however, ignition failures can lead to irreversible damage of a catalytic converter installed in the exhaust gas tract for purifying the exhaust gas. Furthermore, the coating of carbon deposits in the neck region of the intake valve causes flow resistance, which can lead to significant performance losses due to insufficient cylinder filling, especially in the upper load and speed range of the internal combustion engine. In addition, the carbon deposits in the neck region of the intake valve may prevent correct valve closing, which leads to compression losses and thus sporadic ignition failures. This in turn could irreversibly damage the catalytic converter. There is the potential for small particles to break away from the coating of carbon deposits in the neck region of the intake valve and get into the catalytic converter. These hot particles may then cause secondary reaction and corresponding local damage of the catalytic converter. For example, a hole may be burned in the structure of the catalytic converter."

"Globular deposits are found especially on the valve stem downstream from a partition plate in the intake port. Due to the dripping of high-boiling hydrocarbons from the partition plate towards the valve neck or valve stem, globular carbon deposits eventually form there by the sequence of events explained above. These deposits on the valve stem can result in flow deficits due to undesired swirling and turbulent flow around the globular carbon deposits. This may persistently interfere with the formation of stable tumble flow from cycle to cycle."

The most telling thing for me is that Arthur contributes next to nothing else on this forum or any other.

Yet he pops up time and time again on Audi forums all over the WWW whenever anyone questions why their FSI'ed car is down on power.

Call me suspicious but if that doesn't suggest that he does have an agenda, I don't know what does?

Lastly, inspite of his claims to have observed the nil effect of carbon buildup in FSI engines, he has not posted one single controlled experiment to support his contention.

(After all, it'd be easy for someone like him to take some measurements, open up his manifold and clean it, and take some more....oh wait, how many people have already done that?)

Au contraire, there are dozens and dozens of cases of owners out there who have gained substantial levels of performance back post-cleaning. Certainly all our local owners here in the UK rave about the performance of the car post cleaning.

The general consensus is that as a result of carbon build-up, through a mechanism that no-one really understands, the car pulls timing, which combined with a slightly reduced mass flow rate, all contributes to reduced power.

Surely, we can agree that the debate is about how such an issue should be combated?

Anto simply disconnected his knock sensors but that is a little extreme for most of us...

I write the 'same stuff' because the physics do not change...it is not an issue...period...

firstly, if you read the whole post, you will see the personal attacks, just as sims performed...hence my retort...and it's always the same cast of characters: they want to sell oil or porting...

second, the Audi excerpt:
is from the patent, and as stated dozens of times before, in ANY patent, you must state the problem the invention mitigates...this is no 'acknowledgment', just standard stuff, and Audi has mitigated the problem, to the point where no HP is lost...period....a very disingenuous if not outright decietful post...

no surely we don't agree how it should be 'combated', it does not exist...
the issue is created to generate revenue for a few people wiley enough to perpetuate the myth...

I present logical facts/science/engineering, you attempt to make it personal and discredit me...why? what vested interest do you have? I have none...I shot holes thru your previous post, you do not respond, instead you go on the personal attack, class act...

let the FACTS speak for theirselves...and so far I am the ONLY one that as presented any...

all you guys have is 'feeling', no one has disproven my math interpretation, it HAS been confirmed by a PhD thru CFD modelling...not to mention every major manufacturer is using FI a an increasing rate...

[ArthurPE]

the engine will take the same amount of air with or without obstruction...
it's the throttle that limits airflow, nothing else...it is so much larger than the valves it feeds it they have little influence, or in control valve terminology, 'throttling' range...

if the valve orifice x lift were restricted, it is not, because it is much larger than the valve seat opening, but if it were the air velocity will increase and the Q remain the same...
you would have more DP across the valve, but all that needs to happen to offset that is to crack the throttle...

So engines with variable valve lift have this function for what reason? I thought it was to get more air into the cylinder. Honda has had us all fooled for years - all that was required was a bigger throttle!

"Cracking" the throttle is a bit difficult when you've already got it wide open (a prerequisite for maximum power)

This theory that you can overcome a restriction at the intake valves by opening the throttle wider is like telling someone having an asthma attack to open their mouth wider.

I'm mildly impressed by your formulae but if it were that simple then manufacturers wouldn't use race-tracks, mountain passes and wind tunnels to develop cars.

more air at a different RPM, not absolute...to improve low rpm torque...
to change duration and overlap...the volume of the cylinder does not change...if that was the case you could make max torque/power at any rpm...or any size engine....just leave the valve open longer, lol

the valve lift is less under low load, it goes to it's maximum (depending on the system) under load...it's more for efficiency than power, normally you would cam it somewhere in the middle...

as far as opening the throttle for more air, it is fact, not speculation...
that and rpm are the only factors (obviously displacement)

[ArthurPE]

[quote="sims"]Sir, you are an engineer – that I acknowledge.

In this constructive debate about the carbon build up you brought up

• 'Audi haters les miserable'

• the wars,

• Haiti, etc.

• not to listen to a bunch of well to do guys moan about their imaginary issues with their expensive hipo

• that we bitch about things of absolutely no consequence...and don't even exist!

• while others have amputations without anaesthesia

• seek a piece of rat meat to feed their kids

• we could have FED someone or rendered medical aid, or housed them

You said you come here for a diversion - you come here for your own unpleasant agenda, and that is sad

If I choose to raise my concerns, I will but I don’t prevent you from getting on with your life as you suggest I should

There are people on this forum who are impressed with your hyperbole – and some are not and many are silent.

You cast doubt whether I owned an RS4, you cast doubt when I carried out my timing tests and although I explained, you chose not to believe. Do not judge people by your standards.

You have been insulting, rude (and not just to me) and continue to attempt to bully. The old guard were quick enough to pull me up on a “cheap shotâ€

[P_G]

Arthur; from one that has not attacked you word to the wise; rise above what you see and perceive as retorts and insults and refrain from being a lemming.

It's a discussion forum, not Barryboys slagging off site.

[ArthurPE]

Arthur; from one that has not attacked you word to the wise; rise above what you see and perceive as retorts and insults and refrain from being a lemming.

It's a discussion forum, not Barryboys slagging off site.

point taken, hopefully all will follow, I will endeavor to..
thnx

[ArthurPE]

ok, let me catch my breath....
between my last post and this one...
I removed the manifold
took pics
reinstalled
whew!

26k miles, never cleaned

[HYFR]

[ArthurPE]

let me clear up one thing, I have nothing but respect for the UK and her people...
I have trained with para's, and know they are a hard bunch...
my comment was to point out bringing ones country into this, especially as a 'slag' against ones character is not right...

it's one reason I like this forum, you guys (for the most part) are reasonable, level headed and open minded, no politcal crap, etc.
it's a feeding frenzy on some US based forums...we're a bunch of 'cowboys., different that others, but there are none 'better', we are all equal...

[sonny]

I have trained with para's

..and did they try to rape you? lol

Ex Light Div here

[SimonC]

the engine will take the same amount of air with or without obstruction...
it's the throttle that limits airflow, nothing else...it is so much larger than the valves it feeds it they have little influence, or in control valve terminology, 'throttling' range...

if the valve orifice x lift were restricted, it is not, because it is much larger than the valve seat opening, but if it were the air velocity will increase and the Q remain the same...
you would have more DP across the valve, but all that needs to happen to offset that is to crack the throttle...

So engines with variable valve lift have this function for what reason? I thought it was to get more air into the cylinder. Honda has had us all fooled for years - all that was required was a bigger throttle!

"Cracking" the throttle is a bit difficult when you've already got it wide open (a prerequisite for maximum power)

This theory that you can overcome a restriction at the intake valves by opening the throttle wider is like telling someone having an asthma attack to open their mouth wider.

I'm mildly impressed by your formulae but if it were that simple then manufacturers wouldn't use race-tracks, mountain passes and wind tunnels to develop cars.

more air at a different RPM, not absolute...to improve low rpm torque...
to change duration and overlap...the volume of the cylinder does not change...if that was the case you could make max torque/power at any rpm...or any size engine....just leave the valve open longer, lol

the valve lift is less under low load, it goes to it's maximum (depending on the system) under load...it's more for efficiency than power, normally you would cam it somewhere in the middle...

as far as opening the throttle for more air, it is fact, not speculation...
that and rpm are the only factors (obviously displacement)

Nonsense. A restriction is a restriction, whether it be at the air filter, throttle, manifolds, valves, catalysts or exhausts. A build-up of debris on the valve will restrict the airflow and thus the density of the combustion mixture. For maximum power it is important that everything functions as intended. An engine's ability to breathe is hugely influenced by the inlet tract, including valve size and lift. The fact that the RS4 produces so much more oomph than the S4 is testament to how important the finer changes are - higher compession and accurate fuelling are worthless if the engine is compressing a less dense mixture. And whether valve operation is designed to improve power or efficiency they both rely on the air having as uninterupted a journey as possible.

[ArthurPE]

Nonsense. A restriction is a restriction, whether it be at the air filter, throttle, manifolds, valves, catalysts or exhausts. A build-up of debris on the valve will restrict the airflow and thus the density of the combustion mixture. For maximum power it is important that everything functions as intended. An engine's ability to breathe is hugely influenced by the inlet tract, including valve size and lift. The fact that the RS4 produces so much more oomph than the S4 is testament to how important the finer changes are - higher compession and accurate fuelling are worthless if the engine is compressing a less dense mixture. And whether valve operation is designed to improve power or efficiency they both rely on the air having as uninterupted a journey as possible.

not so...I'll do away with the 'nonsense' comments, it serves no purpose...

there is a huge difference bewteen a compressible vs non-compressible fluid...
with a filter there is no alternate path of least resistance...

what's the compression ratio difference RS4 vs S4?
12.5 vs 11 or a 13.6% difference...
does the RS4 have 14% more torque? no only 5% more...so that means the RS4's volumetric eff is LESS (it's displacement is the same) ~7%

let's look at HP 0.93 (vol eff delta) x 340 HP x 12.5/11 x 7800/6800 ~ 412 HP
very close to rated..

actually valves are designed to have a bit of restriction or backpressure, it augments expansion on the down pressure side...like an inverse nozzle...

[SimonC]

Nonsense. A restriction is a restriction, whether it be at the air filter, throttle, manifolds, valves, catalysts or exhausts. A build-up of debris on the valve will restrict the airflow and thus the density of the combustion mixture. For maximum power it is important that everything functions as intended. An engine's ability to breathe is hugely influenced by the inlet tract, including valve size and lift. The fact that the RS4 produces so much more oomph than the S4 is testament to how important the finer changes are - higher compession and accurate fuelling are worthless if the engine is compressing a less dense mixture. And whether valve operation is designed to improve power or efficiency they both rely on the air having as uninterupted a journey as possible.

not so...I'll do away with the 'nonsense' comments, it serves no purpose...

there is a huge difference bewteen a compressible vs non-compressible fluid...

with a filter there is no alternate path of least resistance...

what's the compression ratio difference RS4 vs S4?
12.5 vs 11 or a 14% difference...
does the RS4 have 14% more torque? no only 5% more...so that means the RS4's volumetric eff is LESS (it's displacement is the same) ~7%

let's look at HP 0.93 (vol eff delta) x 340 HP x 12.5/11 x 7800/6800 ~ 412 HP
very close to rated..

actually valves are designed to have a bit of restriction or backpressure, it augments expansion on the down pressure side...like an inverse nozzle...

the engine will take the same amount of air with or without obstruction - Nonsense.

you would have more DP across the valve, but all that needs to happen to offset that is to crack the throttle - Nonsense.

Debris on the valves will reduce airflow and can ultimately cause valve seating problems. I find it hard to believe that Audi allowed for this at design stage, and certainly wouldn't have used such an engine as the basis for dynamometer tests.

The density of the air in the cylinder when the inlet valves close will be lower if there is less clearance at the inlet ports.

The purpose of the 'nonsense' comments are to illustrate the fact that your statements make no sense.

Incidentally, I wholeheartedly agree that a rolling road is best used for comparison purposes and not for absolute figures. Far too many variables.