ELEVENS

I'm not a mechanical engineer, so what follows is what I understand the problem to be. There are several very knowledgeable MEs that post here, so please step in and correct me where you see fit.

The carbon comes from two basic sources. The PCV system and valve overlap ("internal EGR"). Most agree that the cyclonic separator in the RS4's PVC system has proven itself to be very efficient (when functioning as designed and the crankcase oil level is not too high), leaving most of the carbon problem coming from valve overlap. Not much (legally) can be done about that due to federal emission regulations. Maybe an alternate cam profile could work, but that's extremely $$$$, and I doubt if they're even commercially available.

There are some reports that certain newer Audi designs run the engine coolant 10 degrees hotter for carbon buildup reasons. I'm not sure why that would work, but perhaps it has something to do with cyclonic separator efficiency, since a coolant pipe attaches to the body of the separator. Audi literature calls it a "heater".

ELEVENS

Calc. HP +32
Calc. Torque +20
Calc. Wheel HP +20
Calc. Wheel Torque +20

Numbers were corrected for ambient conditions (temp. & humidity).

ArthurPE

your car makes 460+ HP? and 375 lb ft of torque?
peak power at only 7000 rpm?
with a tune and de-cat and 95 oct?
what kind of dyno?

I wished you would have made some 3k to 8k rpm runs, 3rd gear, before and after...please make some now...pleeeease

imho the deposits are not from the egr or blow-by
someone on a different forum actually disconnected his cyclone and vented to atm
0 recirc...in <2000 miles the deposits were back, actually looked similar to yours after 33k miles, at least 70% as much, but as you stated, pics are hard to judge and make it look worse than it is...

another guy put a catch can before the cyclone...he caught almost no oil, minute qtys that the cyclone would have reduced even further...plus it's entrained in the airstream, chances are it will get past the valves and be burnt anyways...

my opinion, it's valve guide seepage...and the egr blows it up/down the intake runners...

ELEVENS

Please ignore the absolute numbers. As we know, we can make the graph say the car is 1000HP just by changing the constants. It's the before/after relative difference, and the area under the curve that's illustrative of the gains from carbon removal.

- The graph was cut off at 7K due to smoothing. Actual motor cutout began at around 7750.

- The car has not been "tuned" and has not been "de-catted"

- These are actual torque data logs using VAG-COM.

- These are 3000-8000K runs. There was no useful data under 3500. Above 7K, the graphs remained constant. Here's a (unlabeled) graph w/ less smoothing. The "power hump" becomes apparent, and the power characteristics beyond 7K is documented.

ArthurPE

does vagcom log time from 3000 to 8000 in 3rd gear
if you start at 2000, punch it, can you determine time from 3k to 8k?

ELEVENS

The following times were pulled directly from the logs. The resolution was 0.1 sec. (sampling rate 10 samples/sec. )

3rd gear 3K-8K rpm times in seconds:

8.74
8.59
8.65
8.44

What are your car's times? If I had know we were bench racing, I would have emptied the Junk out of the Trunk, inflated the tires, and driven in a straight line!

ArthurPE

mine was close to 7.9 avg, but very cold 25-30f, when adjust closer to 8.4 or so
I have times from dozens of cars, maybe 30, over 150 runs by now...
avg 8.2-8.3, good tight std deviation
temp/load adjusted 8.5, yours is 8.6
high was 8.6 until some guy ran a 9 in 110+F temps!
his avg was still 8.6 in those temps!

I have dyno runs, avg is 8.5 sec for a stock car.
avg of 4 or 5 mag tests, 36 to 96 (same speed range) using all gears 8 flat
I have a few mag test, 3rd gear runs, ~8.5 sec also

how much fuel?
alone in the car?

I assume this was the after run...
did you save the data from the 'before' run?
do some more now that you have the hang of it, thanks for sharing

silverRS4

Were any of those 150 runs with Vagcom or were they all done with the lap timer? That's not to say that trends can be seen with any sort of timing method, such as cars that run 9.0+ sec, or a bulk average. The lap timer method reminds of when I was 12 and I timed myself in the 50-yard dash with a stop-watch. There were never any false starts and boy was I fast...especially with new shoes!

kmsnsx

Is this condition covered under warranty? What about CPO warranty? Looking at a 2007 RS4 with 40k and would like to know before buying. Thanks.

RS4bro

Nope...this is not covered. I don't know if I would let this stop you from buy the car but Audi isn't really owning up to the problem.