Putting Carbon Buildup to rest - I hope

[NWS4Guy]

So I got a call at lunch last week from WAZZU_STU, his car overheated and had no signs of water leakage or steam, and thought it was likely his thermostat going - I told him very likely, so he called up AoA and got her on a flatbed. STU just flipped 30,000 miles on our cruise up to Bellingham last week to meet the Vancouver, BC guys - he is the highest mileage B8 S4 I personally know, so I asked for him to get us some shots from the dealer when they pull his supercharger. The results are some very gorgeous and clean intake runners! The only part of the valve with any notable CB is where the shaft narrows far up from where it opens into the cylinder, and very little of it at that. If this is indicative of the other cars out there (and it is from what I have heard from the several techs around the country I have spoken to about this who have seen literally dozens of B8 S4 intakes now with all differnt amounts of mileage) we seem to be doing just fine!

[primaltone]

Thanks for the update. I was a little concerned about this after I placed my order back in November, but this looks promising.

[KarimS3]

Thank you.

[compguy]

I was thinking the same thing...now that there's a recall on the stat we could get some pics of the runners on lots of cars for free. Everyone with mileage should ask their dealers for pics.

[NWS4Guy]

I was thinking the same thing...now that there's a recall on the stat we could get some pics of the runners on lots of cars for free. Everyone with mileage should ask their dealers for pics.

Agreed, though some might not want to take pics (Primetime's dealer didn't) - there is a great chance for a large sampling of cars in this T-stat replacement campaign.

[redrocker55]

So I got a call at lunch last week from WAZZU_STU, his car overheated and had no signs of water leakage or steam, and thought it was likely his thermostat going - I told him very likely, so he called up AoA and got her on a flatbed. STU just flipped 30,000 miles on our cruise up to Bellingham last week to meet the Vancouver, BC guys - he is the highest mileage B8 S4 I personally know, so I asked for him to get us some shots from the dealer when they pull his supercharger. The results are some very gorgeous and clean intake runners! The only part of the valve with any notable CB is where the shaft narrows far up from where it opens into the cylinder, and very little of it at that. If this is indicative of the other cars out there (and it is from what I have heard from the several techs around the country I have spoken to about this who have seen literally dozens of B8 S4 intakes now with all differnt amounts of mileage) we seem to be doing just fine!

That's great stuff!! Amazing how clean that looks.

I'm at 36,000 miles!

[Leor604]

That looks great. Maybe WAZZU_STU blew out all the carbon on Chuckanut.

[Blackhawk878]

Cool, one less thing to worry about.

[richib86]

amen

[svander]

Very reassuring :)

[clochner]

Cool. What are the consequences of carbon build-up? Was this a problem with previous models?

[johnnyb84]

Look at the fifth sticky down on this forum.

[Kandiru]

+5, brake squeal may remain the only issue since they issued TSBs for the clutch
and looks like new trunk lock components may be in place given recent shortages
at factory.

Carbon still does not stop people from paying in excess of 50k for 2007 RS4s:)

[clochner]

Look at the fifth sticky down on this forum.

Cool. Thnx.

[jeffc31337]

Coming from a 2.0T that suffered heavily from intake valve CB this is great news.

My only concern is that instead of on the valves it's just being trapped upstream in the superhcarger vanes/intercooler. Any shots of that(or knowledge of how they looked) by any chance? :)

[AofC_RR]

Jeez that's not bad at all look at 3.2 or 4.2 with the same miles and you'll see some heavy crusting going on.

[Leor604]

Coming from a 2.0T that suffered heavily from intake valve CB this is great news.

My only concern is that instead of on the valves it's just being trapped upstream in the superhcarger vanes/intercooler. Any shots of that(or knowledge of how they looked) by any chance? :)

Would the carbon laden fumes get that far upstream? I would think they would only get a short way back up the runner before being sucked back down on the next intake stroke.

[NWS4Guy]

Would the carbon laden fumes get that far upstream? I would think they would only get a short way back up the runner before being sucked back down on the next intake stroke.

PVC and EGR are pumped through a "labrynthe" of piping under the supercharger, to remove as much suspended oil and unburned fuel particulate, that is then dropped down into the oil filter inlet, to pull the garbage out and let the oil rejoin the engine oil. What is left is fed back into the incoming fresh air right as it enters the supercharger vanes to be pumped back into the cylinders to be burned again. I wouldn't worry about the SC personally, the bearings are all sealed and the twisted vanes are all teflon coated.

[NickS]

Need more information. Is his car chipped? If so, how many miles has he put on it since it was chipped? Does he track his car or drive it hard?

[NWS4Guy]

Need more information. Is his car chipped? If so, how many miles has he put on it since it was chipped? Does he track his car or drive it hard?

He has Stasis (91 tune) for about 5 months, he has done one track event ever in the car (after the tune) no drag strips. It's his DD (obviously with this many miles on it) and drives it hard on occasion - i.e. floors it at least once a week and has some fun, but no "Italian tuneups, drive it like you stole it" kind of driving.

Here's a very recent pic of a RS4 (4.2L) opened up to check for carbon that has 39K miles for comparison -

http://forums.quattroworld.com/rs4b7/msgs/58966.phtml

[NickS]

He has Stasis (91 tune) for about 5 months, he has done one track event ever in the car (after the tune) no drag strips. It's his DD (obviously with this many miles on it) and drives it hard on occasion - i.e. floors it at least once a week and has some fun, but no "Italian tuneups, drive it like you stole it" kind of driving.

Here's a very recent pic of a RS4 (4.2L) opened up to check for carbon that has 39K miles for comparison -

http://forums.quattroworld.com/rs4b7/msgs/58966.phtml

Being stock for the majority of his miles make me wonder what a chipped engine will look like with the same amount of miles on it. I asked about how hard it was run because I'd think those of us who run their cars harder than most would see less carbon buildup over the same period of time.

I've seen all those pictures of the RS4's and my understanding is that Audi made some changes with the newere FSI engine where this wasn't a huge issue anymore? Please correct me if I am wrong.

[NWS4Guy]

Yes, the assumption (mainly from the A4 people's results) are that those who DD their cars less than 10 miles one way have more issues as the engine doesn't get up to temp enough to back the carbon off - sound reasoning, unfounded still though, so could be accurate might not be.

APR leans things out some, so there may well be less likelihood, we'll see - I hope to get pics of mine (approaching 20K total, 7K with tune) when mine goes under the knife for the T-stat.

Our engine has a new labrynthe system (explained above) that is supposed to act like a catch can, and dump the gunk down into the oil system right before entering the oil filter to clean it up. Also they have put in a new (haha!) higher temp T-stat with this car, to bring engine temps up about 8-10 degrees F in order to supposedly help the engine run hotter and better bake the valves clean.

[NickS]

Yes, the assumption (mainly from the A4 people's results) are that those who DD their cars less than 10 miles one way have more issues as the engine doesn't get up to temp enough to back the carbon off - sound reasoning, unfounded still though, so could be accurate might not be.

APR leans things out some, so there may well be less likelihood, we'll see - I hope to get pics of mine (approaching 20K total, 7K with tune) when mine goes under the knife for the T-stat.

Our engine has a new labrynthe system (explained above) that is supposed to act like a catch can, and dump the gunk down into the oil system right before entering the oil filter to clean it up. Also they have put in a new (haha!) higher temp T-stat with this car, to bring engine temps up about 8-10 degrees F in order to supposedly help the engine run hotter and better bake the valves clean.

Yeah, only time will tell I guess.

Good info about the newer t-stat. Do you mean the ones Audi is replacing currently are the newer, higher temp t-stats?

[NWS4Guy]

No they put in the higher temps when the car was released in EU back for MY09, ironic that A) they put in new higher temp ones which failed, and B) that they chose a design for these which fails CLOSED.

I'd assume the new replacements also have the same "higher than the Audi's of old" temps, my oil temps will tell me.

[Leor604]

No they put in the higher temps when the car was released in EU back for MY09, ironic that A) they put in new higher temp ones which failed, and B) that they chose a design for these which fails CLOSED.

I'd assume the new replacements also have the same "higher than the Audi's of old" temps, my oil temps will tell me.

Failing CLOSED is insane. Is there a technical reason they would design it that way? BMW's fail open,which sucks when it happens in winter, but at least you don't torpedo your engine.

[NWS4Guy]

Unfortunately, Audi didn't personally consult me on anything regarding our cars, so I can't really comment - only conjecture

[Leor604]

Unfortunately, Audi didn't personally consult me on anything regarding our cars....

Fools!

[JimmyBones]

Failing CLOSED is insane. Is there a technical reason they would design it that way? BMW's fail open,which sucks when it happens in winter, but at least you don't torpedo your engine.

Even the older 1.8T thermostats failed closed and would overheat fast. I had a TT go from halfway between cold and operating temp to red hot in a block.

[Chestlock]

Fools!

+1

This is great news though Neal! Thanks for the post, and thanks to STU for getting the pic

Not wanting to jump the gun here, but lets get rid of the sticky

[NWS4Guy]

+1

This is great news though Neal! Thanks for the post, and thanks to STU for getting the pic

Not wanting to jump the gun here, but lets get rid of the sticky

I was thinking we might be able too soon as well. I posted this info in the "mega thread" it refers to.

[jlused]

It would be great if carbon build-up was a non-issue with the 3.0T, as I'm considering a B8 S4. Before we conclude there's nothing to worry about, does anyone have pics of the intercooler vanes / supercharger from a car with decent mileage? It may be the case that the carbon / gunk is simply getting caught further upstream.

[NWS4Guy]

It would be great if carbon build-up was a non-issue with the 3.0T, as I'm considering a B8 S4. Before we conclude there's nothing to worry about, does anyone have pics of the intercooler vanes / supercharger from a car with decent mileage? It may be the case that the carbon / gunk is simply getting caught further upstream.

Search for a post from decksurgeon in this forum, he has a post with pics if his SC removed and you can see some caramel coloring on the IC vanes, nothing much really other than discoloration, looks good.

[jlused]

Search for a post from decksurgeon in this forum, he has a post with pics if his SC removed and you can see some caramel coloring on the IC vanes, nothing much really other than discoloration, looks good.

Thanks, I'll have a look. Hopefully Audi has worked out a solution. I'm considering a S4 or M3 sedan, but there's some rumors of bearing failures in the M3's S65 motor. I'll keep my eye on both potential issues and make my decision in the summer.