Even the mighty Porsche DI succumbs to deposits

[Gary Allan]

Quote:
We know that this is an issue that only seems to be happening in a very small number of overall in-service units.


This we do not know. We only have no official recognition of it from the manufacturer.

For all we know, half of the people that bought one, haven't a clue of what a properly running one feels like and/or could care less what the cause is and merely take to a shop and say "FIX". The fixer and the owner may not be internet hounds.

 

[RI_RS4]

pitzel

you are the one making conjecture and then asking me to prove you wrong. I can't do that. It doesn't work that way. The burden of proof is on you, not me.


I do, however, have years of research on DI IVD problems as supporting evidence, and absolutely none of the research points to oil over service as a cause.

 

[Gary Allan]

Save me some back reading, RI.

Out of those showing similar IVD's ..has a good percentage of them adhered to the OEM fluids and OEM service intervals? That is, seeing a fuel laden and high Fe UOA ..and leaving the OEM spec'd fluid in for the OEM spec'd service interval..even with track time?

 

[RI_RS4]

OEM fluids. OEM service interval. Here are two owners, one in the UK, one in the US

Originally Posted By: "pippyrips"
Over the past few months I’ve become concerned by the threads relating to oil/carbon build-up in B7 inlet manifolds. I've also been interested in SilverRS4 & Anto's threads about developing the inlet manifold to help increase airflow and performance.


As I plan to keep the car for the long haul, I wanted to be sure that everything was as it should be inside my engine as well as seeing what could be done to improve an already great car - further.


Not having the skill/experience /time/ knowledge etc to do this sort of work myself, I needed to find someone capable of doing it for me. Since I’ve been around the Audi scene, I’ve heard nothing but good things about MRC Tuning so got involved in a conversation with them around what could be done.


These conversations culminated in me dropping my car off at MRC last Saturday for a week of work, focusing on:


• Investigating and cleaning any build-up in and around the inlet tract
• Testing a ported and polished inlet manifold
• Improving exhaust flow
• Custom mapping all of the above into one neat package.


MRC wanted to approach the work as a development programme, so it was important to have an independent assessment of results as the week progressed. Surrey Rolling Road was chosen for this so I took my car there for a benchmark dyno before any work commenced where she came in at 390.4bhp.


With the maker set, MRC took the car to their workshop and proceeded to take off the original manifold, only to be confronted by quite a mess:


http://i10.photobucket.com/albums/a140/pippyrips/DSCN3437-1.jpg
http://i10.photobucket.com/albums/a140/pippyrips/DSCN3439-1.jpg
http://i10.photobucket.com/albums/a140/pippyrips/DSCN3441-1.jpg
http://i10.photobucket.com/albums/a140/pippyrips/DSCN3442-1.jpg
http://i10.photobucket.com/albums/a140/pippyrips/DSCN3443.jpg
http://i10.photobucket.com/albums/a140/pippyrips/DSCN3445.jpg


Although the build up looks sticky, this was only surface deep and underneath it was rock solid and baked on.


Around 10 hours and some serious elbow grease later the guys had managed to clean up all of inlet and valves leaving them good enough to eat your dinner off!:

http://i10.photobucket.com/albums/a140/pippyrips/clean1.jpg
http://i10.photobucket.com/albums/a140/pippyrips/clean2.jpg
http://i10.photobucket.com/albums/a140/pippyrips/clean3.jpg


We plan to monitor any further build up in the intake by taking off the manifold in 1500 miles before sorting the problem once and for all.


With the valves cleaned, MRC continued by fitting a ported and polished inlet manifold they had prepared and headed off to Surrey Rolling road to measure the difference, firstly with just the stock map and then by applying their own custom map.


The results were:


http://i10.photobucket.com/albums/a140/pippyrips/RS4Dynoresultscleanandrevisedman-1.jpg


Blue line – Car in stock form
Red line – Clean inlet, modded manifold, stock map
Turquoise line - Clean inlet, modded manifold, MRC map


So there it was the magic 414bhp with torque improvements to boot!


Buoyed by the good results the guys took the car back to their workshop and focused their attention on the exhaust. A day and a pair of free flowing downpipes later the car was finished and ready to go back to SRR to measure the final results – here they are...


http://i10.photobucket.com/albums/a140/pippyrips/RS4Dynoresultscollective.jpg

Red line – stock car
Pink line – Clean inlet, modded manifold, stock map
Blue line - Clean inlet, modded manifold, MRC map
Green line - Clean inlet, modded manifold, free flow downpipes & MRC map


At this point it’s probably worth reminding everyone SRR is completely independent to MRC and has no interest or benefit in artificially inflating these results.


To say I am pleased is an understatement. The car is noticeably stronger all over the rev range and much more responsive than before with increased torque that almost feels like a mini turbo has been bolted on – oh and the soundtrack :shock: 8)


I’d like to thank Anto, Silver & Caldy for your help and advice along the way, but most of all I would like to thank Lucas, Doug & Minea at MRC for doing such a great job. They are a top bunch who are true enthusiasts and will be the only people to work on my car from now on.


MRC will be launching their new website in 2 weeks or so and will be featuring my car and all that was involved in a step by step blog. I’m sure they will do a far better job than me in detailing the work but in the meantime if anyone else is interested in following a similar path, give them a call – you won’t regret it!!


Originally Posted By: "pippyrips"
Thanks for the comments guys, to answer a few questions the car is a 56 plate with 19,000 miles on the clock and up until now has been fully serviced by Audi in accordance to their service schedule.

As for using Wynn's in between now and opening her up again - probably not. MRC have a plan to stop the buildup from occurring in the first place so we will be sorting that next time they have the car, and we are keen to see how quickly it builds up so won't want to help it inbetween.

How does she drive? I’ve just come back from an early morning drive where I found myself laughing out loud at certain points! It's only now I have driven her on roads that I am familiar with that I have properly noticed the difference.
The engine no longer feels like a lazy V8, instead is now aggressive and very responsive with much more torque , the drone famous milltek drone at low revs has gone and part throttle driving and fuel consumption is the same as it ever was.

I've attached another graph which is a little less busy than those above showing before and after performance. I have gained up to 50bhp iand 40ftpd of torque in places over the rev range - not bad for an N/A engine!!

http://i10.photobucket.com/albums/a140/pippyrips/RS4Dynoresults.jpg

I love my car :mrgreen:



Quote:
“I’ll try to get the whole history as brief as possible. It’s lengthy, but hopefully informative.

From the time the car was broken in, the cold starts were frequently rough and power delivery was erratic. The roughness should not be confused with a hunting or oscillating idle. It was caused by misfiring, as verified with Vagcom. It eventually got to the point when there would be 30-40 random misfires in the first 15 seconds. First oil change was at 4k by the dealer.

By 8k miles, I had been in twice for “coil” issues to “correct” the CEL’s caused by the misfires. The coils were not the problem. The Service Mgr (not the SA, who was clueless) decided the fuel system should be checked. Four injectors failed the leak-down testing. Upon removing the intake to replace all 8 injectors at 8k miles, they discovered a disturbing amount of buildup on the intake valves. I saw the buildup, but did not take any photos. The dealer did a very good job of cleaning them and with the new injectors, the car ran much, much better. There have been no misfire issues since.

I have hooked up Vagcom several times after the car has been sitting for 2-3 days and zero misfires are recorded – the engine fires up nicely, just as it should. The dealer used a fair amount of solvent when they cleaned the valves, so I changed oil at 8k, using the Castrol TXT synthetic available from the dealer. At 9k miles, I swapped in my ported intake. Low and behold, after only 1000 miles on a good 501/502 oil, the intake valve buildup was already at least 1/2 of what it was at 8k. I had figured that with good injectors that were no longer leaking fuel into the cylinders when the engine was off, there would less fuel dilution of the oil, less oil vapor in the crankcase air stream and much less buildup. Apparently not.

So I cleaned the valves (major PITA), and decided to start using the RLI 5W-40 oil and fuel conditioner. At this point the car was running very strong. At 11.5k miles, I swapped in my version 2 ported manifold. After 2500 miles on the RLI oil, there was some buildup on the valves, but it was minimal. 500 miles later, I swapped manifolds again and of course the valve condition hadn’t changed much. The buildup rate is definitely slower with the RLI oil.

So what have I learned? 1) The high performance nature of the RS4 engine means it volatizes a lot of oil, plain and simple 2) Generally speaking with FSI engines, rough cold starts and misfires are probably injector related – a bad coil would misfire all the time and minor valve buildup apparently doesn’t cause misfires 3) The injector problems are isolated and may be due to a manufacturing tolerance issue 4) I’ve used Tier 1 Shell fuel exclusively, it may keep the fuel system clean, but it does absolutely nothing for intake valve deposits on a FSI engine 4) A good fuel conditioner will help with maintaining clean injectors and minimizing combustion chamber deposits, but with a FSI engine, its affect on the intake valves is minimal 5) Oil chemistry can make a difference with the rate of buildup

 

[Rickey]

This is an interesting thread....my '07 Solstice GXP is a 2.0 turbo DI of the Ecotec family.
24k miles and no detectable decrease in 1/4 or 0-60. No warm up issues either.

A number of possible causal factors have been discussed.

Maybe I missed something....
I wonder if reversion from valve timing overlap at the end of exhaust/beginning of intake has been considered as an additional possible causal factor?
My understanding is that increased valve timing overlap boosts high rpm breathing and is sometimes used as EGR.

A catch can in the PCV might prove useful to minimize one avenue of contamination.

Rickey.

 

[Gary Allan]

Quote:
A catch can in the PCV might prove useful to minimize one avenue of contamination.


Industrial grade demister pad would be my recommendation.

 

[pitzel]

Originally Posted By: RI_RS4
OEM fluids. OEM service interval. Here are two owners, one in the UK, one in the US


4k is *not* the OEM service interval, even for an initial fill. And leaky injectors on a brand new vehicle, that's a potential contributor. Maybe some vehicles are receiving pre-delivery oil changes, ie: they've been sitting on the lot for 6-8 months, unsold, and following 3 months/3000 mile folklore.... Just reading the rants over at TDIclub, VW/Audi dealers seem to be often untrustworthy as to using the proper types of oil, especially when 5W-30 bulk barrel dino is $1/L, and the proper spec oil is $12/L. Huge incentive to cut corners unless a customer is literally standing over you observing oil being poured in from labelled containers.

The 3rd response you quoted actually very highly supports my assertion that over-maintenance or innappropriate oil selection (independant of what the manufacturer specifies) could be a significant contributing factor. In fact, the poster claims that a disproportionate amount of the buildup observed on the valves occurs in the first 1000 miles of operation after the oil change.

I agree that modifying the PCV system ultimately might be the engineering fix required if, indeed, this issue cannot be resolved by tweaks to lubricant specifications, or increased compliance to a maintenance schedule. But reduced PCV vacuum imposed on the crankcase also has its own set of consequences as well.

 

[RI_RS4]

Rickey

That's nice to hear. Maybe GM did their homework with the Turbo DI Ecotec engine.

 

[RI_RS4]

Originally Posted By: pitzel
Originally Posted By: RI_RS4
OEM fluids. OEM service interval. Here are two owners, one in the UK, one in the US


4k is *not* the OEM service interval, even for an initial fill. And leaky injectors on a brand new vehicle, that's a potential contributor. Maybe some vehicles are receiving pre-delivery oil changes, ie: they've been sitting on the lot for 6-8 months, unsold, and following 3 months/3000 mile folklore.... Just reading the rants over at TDIclub, VW/Audi dealers seem to be often untrustworthy as to using the proper types of oil, especially when 5W-30 bulk barrel dino is $1/L, and the proper spec oil is $12/L. Huge incentive to cut corners unless a customer is literally standing over you observing oil being poured in from labelled containers.

The 3rd response you quoted actually very highly supports my assertion that over-maintenance or innappropriate oil selection (independant of what the manufacturer specifies) could be a significant contributing factor. In fact, the poster claims that a disproportionate amount of the buildup observed on the valves occurs in the first 1000 miles of operation after the oil change.

I agree that modifying the PCV system ultimately might be the engineering fix required if, indeed, this issue cannot be resolved by tweaks to lubricant specifications, or increased compliance to a maintenance schedule. But reduced PCV vacuum imposed on the crankcase also has its own set of consequences as well.


pitzel

Get real. the oem interval is 5K. Thus the owner changed 1K early. This is neither uncommon or unusual, and should not be a big deal. At 8k he had misfire problems that required service, when the intake valve deposits were discovered. Audi is on the verge of requiring it's dealers in the US to order walnut shell blasters for intake cleaning, because of significant problems across the entire engine line.

You seem to be very selective in your "facts". The 1st set of postings was from an owner in the UK who followed the service intervals to the letter.

I'm beginning to think that you are way to vested in this to be just a casual outsider.

 

[Gary Allan]

LightAudiman vs. DarkAudiman.

 

[rationull]

I don't really have a dog in this fight at all, nor do I know much about or have any history with DI engines. But I have the following observation:

Pitzel: You're claiming that this problem is partially caused by OCIs that are too short, and using the manufacturer recommendation as a yardstick to judge whether an OCI it too long, too short, or just right. This leaves one of two possibilities:

1) The manufacturer does not know this problem is caused by short OCIs and thus picked their recommended OCI without consideration for this problem. In this case, who's to say the recommended OCI is the correct one? It seems like just another arbitrary interval with respect to the IVD problem.

2) The manufacturer did discover this problem during testing and correlated it to insufficient OCIs, and thus knows that OCIs should be longer than a certain interval. Wouldn't their maintenance recommendations then specifically indicate that you should NOT change your oil earlier than recommended?

 

[pitzel]

Originally Posted By: rationull

Pitzel: You're claiming that this problem is partially caused by OCIs that are too short, and using the manufacturer recommendation as a yardstick to judge whether an OCI it too long, too short, or just right. This leaves one of two possibilities:

1) The manufacturer does not know this problem is caused by short OCIs and thus picked their recommended OCI without consideration for this problem. In this case, who's to say the recommended OCI is the correct one? It seems like just another arbitrary interval with respect to the IVD problem.


I think auto industry engineers often live in a fantasy world where everyone obeys recommendations to the letter, they use the correct lubricants, dealers don't scam customers by substituting 5W-30 dino for the $12/L lubricants, etc. The 'real' world doesn't quite work like that.. European engineers may not even be, for a moment, mindful of the fact that [North] Americans have this every 3000 mile love affair with their local quickie lube.


Quote:

2) The manufacturer did discover this problem during testing and correlated it to insufficient OCIs, and thus knows that OCIs should be longer than a certain interval. Wouldn't their maintenance recommendations then specifically indicate that you should NOT change your oil earlier than recommended?


Engine vendors have been aggressively pushing for lower volatility in motor oils. They recognize that there are serious problems out there with respect to what gets sucked into intakes.

Manufacturer recommended OCI's seem to be based more on marketing, than actual science. A Honda bought in Detroit = 10k mile OCI recommendation. A Honda bought across the river in Windsor, Canada = 8k km OCI recommendation. Same car sold in Europe may very well have a 15-20k mile OCI or better, even with the much harsher environment present in European driving. The average quickie-luber will say 3k miles/3 months for obvious reasons. Amsoil salesmen, 25k. You get the point. It makes no sense whatsoever.

Originally Posted By: "RI_RS4"
I'm beginning to think that you are way to vested in this to be just a casual outsider.


...yet I'm suggesting a course of action that stands to benefit nobody except for, perhaps, the operator of the engine, if they save money on unnecessary oil changes, and keep the fumes of newly changed oil out of their intakes as much as possible.

 

[RI_RS4]

Pitzel

The problem I have is that you offer zero corroborating data to support your hypothesis.

 

[buster]

pitzel, OEM's do test and specify drain intervals. It's not based on just marketing.

My Toyota consumed 1qt per 3k miles and ran like new with 180k on it. ALL oils today are low volatile. Just look at Amsoil's testing. Most are all < 10% now. It's more than just volatility.

 

[pitzel]

Originally Posted By: RI_RS4
Pitzel

The problem I have is that you offer zero corroborating data to support your hypothesis.


Not to beat a dead horse, but you actually offered a significant amount of corroborating data to support my hypothesis, in the form of those quotations from operators. One operator commenting that the first 1000 miles seemed after an OC seemed to cause a lot of buildup. Another operator commenting that his intake underwent accelerated clogging when a volatile material was introduced into the motor oil, to wit: petrol.

And we have evidence that manufacturers are so concerned about the negative effects of high motor oil volatility that they have increased standards on volatility significantly (the new GEOS standards from GM push spec'ed volatility down even further). And we have evidence that manufacturers themselves are pushing long drains to deal with precisely the sorts of issues that I'm talking about.

If you don't like my hypothesis, fine, I can live with that. But don't ignore the evidence, including the evidence that you personally have offered up, in support of it. The standard for publication and research, on BiTOG, fortunately, or unfortunately, is somewhat less than a SAE journal, simply because few of us are actually scientists or engineers (as am I), and fortunately or unfortunately, anecdotal evidence has to be given a much higher weight simply because scientific evidence is often in short supply.


Originally Posted By: "buster"

pitzel, OEM's do test and specify drain intervals.


How the heck do you really justify the difference between European and North American drain intervals then? Or even the difference between Canadian and American? I think cultural differences are a big input -- an engine that's innappropriately serviced with 5W-30 dino that runs 10k won't be permanently damaged within the warranty period (might just be slightly sludged). The euro engine manufacturers can specify 20-30k on the same vehicle because they know the auto servicing industry will respect the manufacturer's requirement for synthetic that will survive without sludge.

Anyways, I have nothing else to add, so I may as well stop posting in this thread. If someone wants to start a new thread on my belief that changing oil frequently is just as good for the intake of an engine, as smoking cigarettes is for a human, be my guest, I'll be a participant.

 

[pitzel]

Originally Posted By: buster

My Toyota consumed 1qt per 3k miles and ran like new with 180k on it.


Your Toyota didn't have a design issue that made it susceptible to the negative effects of high oil volatility. The DI engines do. That's why the traditional logic of, "an extra oil change can never hurt an engine" doesn't really apply here.

 

[Gary Allan]

I don't see where this is a proven flaw, pitzel. As DarkAudiman stated, there's no prohibition on shorter service intervals ..and even without them, problems emerged.

Nope ..I can't quite buy your take on it. You're saying that volatility is the cause ..yet GOBS of volatility will be inherent to the fuel dilution that is a "designed" result of the DI fuel system.

If your theory is true, then every one of these engines should see the same level of IVD ..but either sooner or later. It could never be an IF ..but rather a WHEN.

There's nothing to remove those IVD in the intake stream. There will either be more of or less of ..more deposit forming agents.

 

[cjustice]

High compression engines need to run on 93 octane fuel, like what the manual says... Also, since fuel quality is always in question these days, I would recommend a high quality fuel additive like BG's 44K. (Poly etheramine in the strongest concentration that I've ever seen.) Next best thing in Techron. Do 44k every 10,000 miles or Techron every 5,000 miles and your valves will never look like this again!

 

[Audi Junkie]

As far as "boil off", it seems like any/all light fractions would be long gone after the Hydrocrack process at +500f...

http://en.wikipedia.org/wiki/Fischer-Tropsch_process

I'm not shure what additive suppliers would say about their carrier oils as light fractions, but it seems like something that could be easily addressed.

Another question mark for me would be pure PAOs, lke GC, where are the "boil off" products coming from?

fwiw, as for GC as a Long-Life oil, it does carry the VW's LL spec of 503.01, MB 229.3/5 as well as the venerable BMW LL-01.

Maybe the source of the deposits is oil getting pulled thru the valve stem seals on the intake stroke?

 

[pitzel]

Originally Posted By: Audi Junkie
As far as "boil off", it seems like any/all light fractions would be long gone after the Hydrocrack process at +500f...

http://en.wikipedia.org/wiki/Fischer-Tropsch_process


Since modern oils have NOACK volatility of ~10%, where does that 10% 'go'?

http://www.astm.org/Standards/D5800.htm

Quote:
Procedure C, using the Selby-Noack apparatus, also permits collection of the volatile oil vapors for determination of their physical and chemical properties. Elemental analysis of the collected volatiles may be helpful in identifying components such as phosphorous, which has been linked to premature degradation of the emission system catalyst.


BTW, Fischer-Tropsch is a process for isomerization, not hydrocracking or hydrotreating. And there has not yet been a 'non-volatizable oil' to date, ie: an oil that produces a 0% (or statistically similar) result in the ASTM 5800-8 ("Noack") test.

Quote:

Another question mark for me would be pure PAOs, lke GC, where are the "boil off" products coming from?


PAO manufacturing processes are not purely selective; they produce a distribution of different chain lengths and isomers of olefins. Engineers attempt to tune processes to the desired chain length and isomeric structure, but there are always outliers, and catalysts are not perfectly selective.

Quote:

Maybe the source of the deposits is oil getting pulled thru the valve stem seals on the intake stroke?


Yeah that's a good theory as well, in which case, modifying the PCV will do absolutely nothing to ameliorate the situation.