Pictures of my inlet ports....

[Sims]

You are right Sims, it is your opinion and sadly wrong.

It would be like me coming on to the forum for the first time with no previously stated history and saying the RS4 is crap. How?

Where facts are necessary as in this thread and rsierra's comments they are lacking. I wasn't being rude to him and asked him to expalin his statement. So how is that partisan because that would imply I am a supporter of this subject or a person which I am not or indeed prejudiced because I would have to have formed an opinion of him which I have not?

Esteemed Sir, we must agree to disagree.

[ArthurPE]

You have no clue what you are talking about. The RS4 ECU will <beep> timing in excess of 10 degrees on a consistent basis without throwing a code. I suggest you get VAG COM and do some data logging before posting misinformation.

you are absolutely incorrect...
yes it will <beep> timing, but if the calculated load dependent setpoint is over-ridden a set number of times by the knock sensor code(s) will be set

I could sling some mud, but the arrogence of your incorrect post did that for me...

[ArthurPE]

With respect, IMO your challenge of this newbie does smack of partisanship & a bit of prejudice.

I don't know if what RSierra says makes sense, but do you?

that's because not only is the 'newbie' incorrect, he's smug and arrogent

if the desired and calculated set-point is continuously over-ridden by an error/fault (knock) only a moron would not configure the device to record such events...

[silverRS4]

Lets say the set point (or target) for timing with 90% load at 7000 rpm is 33.5 degrees. With 91 US octane (95 RON), that will never happen - the result will probably be around 24 degrees. With 93 US / 98 RON the actual timing may be 28-30 degrees and only with 95/96 US / 100 RON will the target actually be accomplished. The fact that timing targets can not be met in a closed-loop system is not an "error". The system is that way to handle a wide variety of fuel grades. An RS4 with bad gas will drive around forever with timing 10-15 degrees less than the "target". There is not one thing rsierra said that was incorrect.

[ArthurPE]

Lets say the set point (or target) for timing with 90% load at 7000 rpm is 33.5 degrees. With 91 US octane (95 RON), that will never happen - the result will probably be around 24 degrees. With 93 US / 98 RON the actual timing may be 28-30 degrees and only with 95/96 US / 100 RON will the target actually be accomplished. The fact that timing targets can not be met in a closed-loop system is not an "error". The system is that way to handle a wide variety of fuel grades. An RS4 with bad gas will drive around forever with timing 10-15 degrees less than the "target". There is not one thing rsierra said that was incorrect.

it's an 'error' if it's over-ridden by the knock sensor (a fault condition)
yes, a few times, no error, consistently, as would be the case with carbon, sure as heck would...

I know a bit about these engine controls
I sued BMW and won based on this knowledge...
they argued my engine blew due to over-revs
they said one label = events >8000 n_maxrev and another time of max event over 8000 t_maxrev

I printed the code out and dissected it
actually the events were over 7800, NOT 8000 (8000 was redline)
the time was CUMULITIVE time >7800, not a single event

so in 4000 hrs of operation and 145k miles (all recorded) I approached redline (>7800 out of 8000) ~80 times for a total of 52 sec

I also had to convince (actually that show their expert witnesses knowledge was suspect, ie, discredit) that the service interval was not a fixed reset (they tried to argue I did not do proper oil changes, I had all records and receipts from the dealer) but was actually based on service duty, specifically, 666 gal of fuel...
if driven easy 20 mpg x 666 ~13320 miles
driven hard 17 mpg ~ 11322 miles

I know the guys at Cat, Cummins, etc., they all use either Bosch or Seimens, and it's pretty much all the same science, only the application varies...

I also programmed controllers for generators, engines, chillers, boilers, etc., for 10+ years when I started out

[Sims]

...I know a bit about these engine controls
I sued BMW and won based on this knowledge...
they argued my engine blew due to over-revs
...

Serious question -So why did the engine blow? I know you like BMW engines and believe they are the best.

[ArthurPE]

...I know a bit about these engine controls
I sued BMW and won based on this knowledge...
they argued my engine blew due to over-revs
...

Serious question -So why did the engine blow? I know you like BMW engines and believe they are the best.

bad oil pump, bad rod bearings...both were supposedly addressed during a recall/service action...

long story short:
I had the SIB done, the engine failed within 5k miles
I negotiated a deal for a rmfg BMW motor
it failed a short time later, within warranty, (I determined it slipped thru the cracks and had the old bearings and oil pump, don't ask how I found out )
they blamed it on over-revs, I sued and won, BMW NA
they initially tried to say I rev'ed to 8400, I said not possible, unless mechanically, they said I did...and it happened within 10 miles of the failure..

I pointed out it happened at 30k miles, over 110k miles and 2 engines ago!
not even on this engine!

this is all in the ECU...the mileage they said it occured, was the actual ECU mileage, not the over rev mileage, lol, clueless...
in addition there is an over rev flag >8200, that was reset when the rmfg engine was installed...guess what, it was set to '0', ie, no over-rev...

[lugars4]

Lets say the set point (or target) for timing with 90% load at 7000 rpm is 33.5 degrees. With 91 US octane (95 RON), that will never happen - the result will probably be around 24 degrees. With 93 US / 98 RON the actual timing may be 28-30 degrees and only with 95/96 US / 100 RON will the target actually be accomplished. The fact that timing targets can not be met in a closed-loop system is not an "error". The system is that way to handle a wide variety of fuel grades. An RS4 with bad gas will drive around forever with timing 10-15 degrees less than the "target". There is not one thing rsierra said that was incorrect.

it's an 'error' if it's over-ridden by the knock sensor (a fault condition)
yes, a few times, no error, consistently, as would be the case with carbon, sure as heck would...

Most engines are running with some degree of correction from the "ideal" timing map. The knock sensors primary use is to allow the ECU to adjust the timing in a closed loop control. The feedback to the control loop is the knock sensor. The ECU will advance the ignition timing until either it reaches the map limit, or knock is detected.
This control method is required when a mixture of fuel grades are available on the market, and every tank of fuel through an RS4 will not be higher octane....

Put simply;
lower octane fuel = detonation at the map timing limit = timing pull from the ECU = less performance / power. (NO fault codes)

Carbon buildup = pre-ignition at the map timing limit = timing pull from the ECU = less performance / power (No fault codes in most cases)

The effects of carbon deposits and low grade fuel in this case are comparable. The amount of timing pull from the two is quite possibly very similar.

All engines have to be adaptable to conditions such as air intake temps, fuel grade, altitude, cylinder temperatures.... And one of the features of this adaptability is "timing adjustment" by feedback from the knock sensors, which is not considered a fault to the ECU unless it is over a limit, defiantly beyond most mild detonation conditions ( more than CF = 10) .

[S2tuner]

rsierra is absolutely correct and ArthurPE is misinforming indeed. An ECU can pull up to 15-20 degrees of timing in case of bad fuel being used, and yet it won't throw a code, or only in very marginal cases which most people will never experience. Arthur, why don't you go and fill up your car with some of that lovely 87 octane you guys have over the pond, and then report back with fault code readouts, because I hardly expect to see ANY codes.

[ArthurPE]

this is true, BUT, if the setpoint is continuously over-ridden by using 87 octane fuel, you will get an error, much in the same way if you attribute continuous deposits to consistent detonation...

now the limits of event count may vary, lower where good fule is available, say Germany, and higher where the fuel grade is more variable, say Mexico...

but if the torque/load prescribed setpoint is continuously over-ridden by the knock sensor (and I don't mean to the limit) you will get an error...it costs nothing to do so, a few lines of code...

the knock sensor is a safety or limit, not a primary control variable (it's a reset or trim variable, much like the O2 sensor), load is...it only intervenes when the selected map set-point initiates detonation, and that is a non-normal operating condition...

if it happens occassionally, say too low gear up a hill, it will not be a 'fault', if it happens all the time, under varying conditions, as would be the case with bad fuel or deposits, it will...

Lets say the set point (or target) for timing with 90% load at 7000 rpm is 33.5 degrees. With 91 US octane (95 RON), that will never happen - the result will probably be around 24 degrees. With 93 US / 98 RON the actual timing may be 28-30 degrees and only with 95/96 US / 100 RON will the target actually be accomplished. The fact that timing targets can not be met in a closed-loop system is not an "error". The system is that way to handle a wide variety of fuel grades. An RS4 with bad gas will drive around forever with timing 10-15 degrees less than the "target". There is not one thing rsierra said that was incorrect.

it's an 'error' if it's over-ridden by the knock sensor (a fault condition)
yes, a few times, no error, consistently, as would be the case with carbon, sure as heck would...

Most engines are running with some degree of correction from the "ideal" timing map. The knock sensors primary use is to allow the ECU to adjust the timing in a closed loop control. The feedback to the control loop is the knock sensor. The ECU will advance the ignition timing until either it reaches the map limit, or knock is detected.
This control method is required when a mixture of fuel grades are available on the market, and every tank of fuel through an RS4 will not be higher octane....

Put simply;
lower octane fuel = detonation at the map timing limit = timing pull from the ECU = less performance / power. (NO fault codes)

Carbon buildup = pre-ignition at the map timing limit = timing pull from the ECU = less performance / power (No fault codes in most cases)

The effects of carbon deposits and low grade fuel in this case are comparable. The amount of timing pull from the two is quite possibly very similar.

All engines have to be adaptable to conditions such as air intake temps, fuel grade, altitude, cylinder temperatures.... And one of the features of this adaptability is "timing adjustment" by feedback from the knock sensors, which is not considered a fault to the ECU unless it is over a limit, defiantly beyond most mild detonation conditions ( more than CF = 10) .

[ArthurPE]

rsierra is absolutely correct and ArthurPE is misinforming indeed. An ECU can pull up to 15-20 degrees of timing in case of bad fuel being used, and yet it won't throw a code, or only in very marginal cases which most people will never experience. Arthur, why don't you go and fill up your car with some of that lovely 87 octane you guys have over the pond, and then report back with fault code readouts, because I hardly expect to see ANY codes.

afraid not, he is misinformed, either by lack of knowledge or intentionally...

if you put a bad tank of gas in, you will get codes...

[lugars4]

this is true, BUT, if the setpoint is continuously over-ridden by using 87 octane fuel, you will get an error, much in the same way if you attribute continuous deposits to consistent detonation...

now the limits of event count may vary, lower where good fule is available, say Germany, and higher where the fuel grade is more variable, say Mexico...

but if the torque/load prescribed setpoint is continuously over-ridden by the knock sensor (and I don't mean to the limit) you will get an error...it costs nothing to do so, a few lines of code...

the knock sensor is a safety or limit, not a primary control variable (it's a reset or trim variable, much like the O2 sensor), load is...it only intervenes when the selected map set-point initiates detonation, and that is a non-normal operating condition...

I agree that you will get a fault code, but i feel that in most of the cases of carbon induced detonation, the timing pull is only that similar to, for example, filling the tank will low grade fuel, so i would not expect a fault code to be generated in such a case.

I think what is un clear, and would be interesting to know, is at what point would a code become logged.

For example: taken from REVO tuning manuals:


Uploaded with ImageShack.us

[ArthurPE]

that is a good question, but it's not only magnitude, but frequency, duration...

I'm still not convinced that deposits are a mechanism (in a DI engine) to cause 'knock'...
they will in a port injected car, because they will absorb fuel, making for a lean mixture, not an issue in a DI car...

[S2tuner]

rsierra is absolutely correct and ArthurPE is misinforming indeed. An ECU can pull up to 15-20 degrees of timing in case of bad fuel being used, and yet it won't throw a code, or only in very marginal cases which most people will never experience. Arthur, why don't you go and fill up your car with some of that lovely 87 octane you guys have over the pond, and then report back with fault code readouts, because I hardly expect to see ANY codes.

afraid not, he is misinformed, either by lack of knowledge or intentionally...

if you put a bad tank of gas in, you will get codes...

And I do think YOU are misinforming people intentionally, and that you don't know what you're talking about, yet make it look like you know it all. I know it's hard to accept to be taught by someone younger than you are, however, I'm only trying to make you understand that Audi engine management systems are what I breathe day in day out because they are my job and also my hobby. Please stop talking nonsense and accept to learn where you don't know what you're talking about, or stop posting here, because your obvious lack of knowledge of Audi Bosch MED9 engine management systems is plain annoying.

[S2tuner]

Arthur, all arguments aside, why don't you simply go and fill your car up with 87 AKI fuel and report back here? Just because you want to be contradictive and because you *think* you're right? I think you're wrong, but I'll be glad if you prove me otherwise.