Valves- carboning up

[2manytoys]

Using the analogy above, Records vs CD's, that is the problem here, those people saying Records are fine have never heard the CD. There are a few on here too.

People are really missing the point. It is "does carbon cause power loss" not have all cars got problems... what the??. I'm sure some are fine, and that's the hope obviously otherwise we'd all be selling our cars... der

Please all people that have done the 3000-8000 test, then cleaned their valves and done it again put up their hand. If you ask the people that have cleaned their valves you'll get the real answer. All the rest is speculation and theory (they said the Titanic couldn't be sunk when they designed it, then it met the real world)

Actually, is there anyone that has cleaned their valves and thought "what a waste of money or time"

[HYFR]

Actually, is there anyone that has cleaned their valves and thought "what a waste of money or time"

if the carbon comes back after ~2k then probably

[sonny]

Please all people that have done the 3000-8000 test, then cleaned their valves and done it again put up their hand. If you ask the people that have cleaned their valves you'll get the real answer. All the rest is speculation and theory (they said the Titanic couldn't be sunk when they designed it, then it met the real world)

I will let you know next month

[P_G]

A point to consider though; how do you know the rated bhp of the engines were recorded with a clean manifold and valves? Every comment 2manytoys has made thus far assumes this, so those that clean their valves and then do the test may produce even higher bhp values, but it is in a false environment because no engine, even non FSI / GDI engines remains as pristinely clean as it would do if it were just cleaned.

My understanding of the power rating process (which is by no means gospel) of an engine is it is not done on a couple of runs on an engine straight out of the box and then put into print. It is a process taken over a certain period of time during which time carbonisation is going to happen. How do we know this; because like said after 2k miles most of the cleaned engines have carbon depoists again so it is likely that if not immediate the carbonisation starts pretty soon after first running and load through it.

What surely needs to be understood first is when Audi are rating these engines what they categorise as 'significant' in terms of air flow reduction and potential power loss if they describe the carbonisation which they appear to know happens as 'not significant'.

[sonny]

Yes agree, could later SW updates have an effect on the amount of build up. example, 2 cars both of the same year, clean valves at same time one on SW0090 and one on original SW, would there be a significance build up over a longer period of time in carbon deposits ? I suppose we wont know unless tested. It would be interesting if there was.

[ArthurPE]

most true audiophiles would say the opposite: records sound better, hence the market for 10k$ turntables...they also have 10k$ CD players, and still maintain records sound better...but in the end, this is subjective...measuring something with a stopwatch is subjective...
whether you agree or not, if done carefully and compensated for temp & weight, it is a true, relative, objective, measurment of performance...that is why most think dyno = bogus, drag strip = real...

and again, with the veiled attacks on those who disagree with your questionable, variable and vague position...

I have 100's of sample points from dozens of cars, more than a few cleaned, average mileage >30k, some as high as 70k..they all have carbon, yet all perform the same as those cleaned, or new, and as tested by magaizines...a car with 70k miles is the same as a car just cleaned...

anyone who spent all that money cleaning valves will never admit it a waste, that would imply they made a mistake, people have a hard time doing that, ego...the same as the guy who thinks he can hear a difference between $100 speaker cables and $1000 speaker cables...

you are the only one offering wags' and speculation, I'm offering hard facts and numbers, but since they don't fit your case, you dismiss them, and attack anyone who does place weight on them...

you have 0 understanding of the mechanisms at play, yet you dismiss anyone who tries to share information with you, you have a closed mind, and are a 'hopeless case', as far as trying to explain what is going on....

Using the analogy above, Records vs CD's, that is the problem here, those people saying Records are fine have never heard the CD. There are a few on here too.

People are really missing the point. It is "does carbon cause power loss" not have all cars got problems... what the??. I'm sure some are fine, and that's the hope obviously otherwise we'd all be selling our cars... der

Please all people that have done the 3000-8000 test, then cleaned their valves and done it again put up their hand. If you ask the people that have cleaned their valves you'll get the real answer. All the rest is speculation and theory (they said the Titanic couldn't be sunk when they designed it, then it met the real world)

Actually, is there anyone that has cleaned their valves and thought "what a waste of money or time"

[ArthurPE]

Actually, is there anyone that has cleaned their valves and thought "what a waste of money or time"

if the carbon comes back after ~2k then probably

lol, true

the one pic posted here showed them in, iirc, 1200 miles, all fouled up, almost as bad as 20k miles...seems to happen very quickly, then taper off, like any natural deposit formation, a natural log curve...

[ArthurPE]

you are exactly correct: I've posted the test method/procedure on here

it specifically states that carbonization and deposits (in the amount normally encountered) are to be present...the engine is not pristine, and usually has many hours of run in, which makes sense, because it would make more power after break-in...and yet it is still rated at 420HP...go figure...

agree: to assume Audi did not factor normal operating conditions into their power rating is silly, they KNOW deposits form, they run engines with many hours, under load, before rating them, so the ratings would seem to include any 'losses' due to carbon...the testing agencies would insist upon this....

A point to consider though; how do you know the rated bhp of the engines were recorded with a clean manifold and valves? Every comment 2manytoys has made thus far assumes this, so those that clean their valves and then do the test may produce even higher bhp values, but it is in a false environment because no engine, even non FSI / GDI engines remains as pristinely clean as it would do if it were just cleaned.

My understanding of the power rating process (which is by no means gospel) of an engine is it is not done on a couple of runs on an engine straight out of the box and then put into print. It is a process taken over a certain period of time during which time carbonisation is going to happen. How do we know this; because like said after 2k miles most of the cleaned engines have carbon depoists again so it is likely that if not immediate the carbonisation starts pretty soon after first running and load through it.

What surely needs to be understood first is when Audi are rating these engines what they categorise as 'significant' in terms of air flow reduction and potential power loss if they describe the carbonisation which they appear to know happens as 'not significant'.

[SR71]

I suggest everybody here is using the figures to advance their case, not just a select few...

I suggest the positions of some are so entrenched, that likewise, their egos will never admit to the degree of truth in the opposing position.

Which is a shame.

I'll say it again, I believe I and Rob are the only people who have run a dirty car against a clean car on the same day, same time etc etc...albeit I must keep referring the honourable gentlemen as to the qualfications that apply in these tests.

In addition, VAGCOM, will demonstrate a ~2% difference in airflow in a clean versus dirty engine.

I suggest this is the most accurate test of whether airflow is affected rather than a dyno or an acceleration test with a huge number of dependent variables - weight, ambient conditions, SW version, incline, tailwind, measurement error etc etc. Why the reluctance to embrace this type of testing? Because you need VAGCOM?

Were the R8's that are tested fresh out of the factory full of carbon?

I think not.

But I do agree with P_G:

What surely needs to be understood first is when Audi are rating these engines what they categorise as 'significant' in terms of air flow reduction and potential power loss if they describe the carbonisation which they appear to know happens as 'not significant'.

This is exactly what we need....for Audi to clarify what they saw when they engine dynoed the car, what the saw when they chassis dynoed the car, what they expect to happen to the stats over the course of an average ownership cycle.

This was a £55K car.

I don't expect to see my performance take a hit like a £20K 2.0TDi.

And just to clarify, yet again, I totally enjoyed ownership of my B7.

[no_RS]

I think the length of this thread just proves that you can argue this one until your blue in the face and really achieve nothing. It begs the question why companies like Subaru and Mitsubishi under spec their engine outputs, I suspect to avoid on-going arguments about meeting specs.

It would appear to me that Audi are really not interested in getting involved in this one, I suspect the marketing people wanted to specify an output power close to upper limit just to get one over on their competitors and the result is a 20 page thread about it. Suggest this thread is closed and any further queries about valve carboning up are referred here.

[PetrolDave]

Using the analogy above, Records vs CD's, that is the problem here, those people saying Records are fine have never heard the CD.

Try listening to a pipe organ on vinyl and on CD - the pipe organ on vinyl has much more depth and quality to the sound due to effects that the digitisation cannot accurately reproduce but which your ear can hear.

As with everything, there is no black and white it's always shades of grey.

[PetrolDave]

This was a £55K car.

I don't expect to see my performance take a hit like a £20K 2.0TDi.

That's an unrealistic expectation - your £55k car is subject to the same rules of physics and chemistry as the £20k car, so to expect it NOT to be affected in the same way is just never going to happen.

[Sims]

..I suspect the marketing people wanted to specify an output power close to upper limit just to get one over on their competitors .

That could be for in 2006 Audi claimed a 100ps per litre for this NA engine, higher AFAIK than any of their previous achievements.

And yet the outgoing (in 2006) E46 M3 was already outputting 343ps from it's 3.2 engine i.e. 107ps per litre, and in 2003 the M3 CSL had achieved 112ps per litre. The current M3 outputs 420ps from it's 4 litres i.e 105ps per litre

The outgoing Porsche 996 GT3 in 2005 claimed 106ps per litre, whilst the new 997 one in 2006 claimed 115ps.

The E60 M5, around the time the RS4 was launched, claimed 507ps from it's 5 litres i.e call it 100ps per litre.

So it could well be they were doing their best to match/catch up with their competitors. And the RS5 has now bid 107ps per litre.

It would be good to see what power these make when tested fresh out of the factor, at the dyno and the chassis.

Does anyone here know of claims that RR's are "unfriendly" to any of these NA M & GT3 cars (I accept they are all 2WD), and are the BMW/Porsche forums full of thread after thread complaining about power (they have their own issues vanos,rms, gearboxes etc .

Or is this a problem for all engine manufacturers in future with the new technology, new fuels etc.



P.S. Feel free to challenge my PS numbers for I have not checked them.

[Sims]

Try listening to a pipe organ on vinyl and on CD - the pipe organ on vinyl has much more depth and quality to the sound due to effects that the digitisation cannot accurately reproduce but which your ear can hear.

.

Vinyl is great, to me it is the 4.2 RS4 compared to the 4.2 S4 sort of.

[Sims]

..

In addition, VAGCOM, will demonstrate a ~2% difference in airflow in a clean versus dirty engine.

I suggest this is the most accurate test of whether airflow is affected rather than a dyno or an acceleration test with a huge number of dependent variables - weight, ambient conditions, SW version, incline, tailwind, measurement error etc etc. Why the reluctance to embrace this type of testing? Because you need VAGCOM?

So why is VAGCOM not used more widely. Surely they will have one at the MRC day?