Drop in BHP due to Carbon Build up - Gen 2 997?

[cragswinter]

Or you could dyno before & after de-coking at the same place in similar conditions?

[Wills2]

Ian_UK1 said:

...To clarify again my position on the whole issue of carbon build-up - no I haven't seen direct evidence of this in a 997 DFI engine.

Yes, I agree that we don't have all the information we need yet. Ian

Edited by Ian_UK1 on Saturday 13th November 14:42

At last the true position and I agree with you we don't know but it would be interesting to find out.

[Wills2]

bcnrml said:

Wills2 said:

If you read my post properly I'm not promoting any theory just asking for evidence from people such as yourself who are promoting the theory that the gen2 DFI engine suffers from coking.

Yet earlier,

Wills2 said:

Proof is what we need and as a fellow gen2 owner with 33k on his I would be interested to see the issue if it does infact exist in our engines.

I read your post properly (and I am functionally literate).

All the evidence I've seen points to all manufacturers having problems with coking on direct DFI type engines. Can you provide any evidence to help change my view (said view corroborated with evidence on the internet)? I'm happy to be proven wrong. Provide the links to do so. For his side of the debate, Ian_UK1 has already gone far beyond your own input. I do not own any cars with this engine design (never have), so I don't care from a financial or performance perspective. They're only ever in my hands when they're loaners, and I’m always happy to hand them back (as I did with one on Thursday evening).

Porsche's 15 year history on engines hardly inspires one with confidence. On Ian_UK1's aforementioned thread, I enquired about the DFI in the naive hope that the problem would be minor and I got excellent technical responses that were an education. With evidence.

Wills2 said:

I haven't said it does or it doesn't, I have merely asked for more than internet chat and pictures of other cars.

There's plenty of evidence. Go to Ian_UK1's original thread (do a search) and build your research from there. Educate me: Is the Cayenne engine referred to completely different to yours?

Wills2 said:

I have no rose tinted glasses about my car or Porsche for that matter.

Good. You may not, but there are many others who do, and I think that if you cannot counter the technical analysis (and evidence on here) with arguments of the same standard, you've a responsibility to other porker nuts (aspirants, owners and indeed the less knowledgeable members of the trade) to stop dismissing this kind of thing as internet chat. Global FMCG companies, investment bankers, hedge funds, private equity firms, market analysts and some of the best journalism is based on so-called internet chatter followed by some due diligence. This forum remains amazing in that people will come on here and use the phrase “internet chat” or “internet hearsay” to dismiss a well-argued set of points that are designed to help fellow porkers!

Wills2 said:

And I'm fully aware that absence of evidence isn't evidence of absence.

Good. That’s how I live.

So will you match Ian-UK1's offer in your own way? Why don't you do exactly what you asked him to do? In fact, why don't you all (owners of DFI engined porkers) ask your OPCs (and/or Indies) to give you the evidence? That'd be helpful for all concerned (I imagine the OPCs cannot lose either way so they should be helpful). You might prove this is a myth. You might corroborate it. Just getting pictures - as you yourself noted - would be very helpful.

So, Wills2, please just say when and start a new thread with your pics. That's fair and reasonable, no? Ian_UK1's made an open offer already. Any other takers?

Edited by bcnrml on Saturday 13th November 13:14

I think you are looking for a debate that doesn't exist old boy, Nothing you have quoted from my posts differs from what I have said in this thread.

The 2 quotes you start your reply with say the same thing i.e I'm looking for proof that this condition exists, so why you quote those 2 sentences (I use the term loosely) I have no idea.

1. We don't know if the gen2 engine is coking
2. We haven't seen the inside of a coked gen2 engine.
3. But it might be and until someone scopes one we won't know.
4. Proof would be nice.

I'm not looking to score points but you seem hell bent on trying to make out that I am.

I'm open minded to this but need proof

Edited by Wills2 on Saturday 13th November 17:48

[bcnrml]

Wills2, I'm not picking an argument with you, but the statement below from Ian_UK1 is absolutely accurate and I agree with it completely. Given you didn't quote it, I'm not sure you agree.

Ian_UK1 said:

To clarify again my position on the whole issue of carbon build-up - no I haven't seen direct evidence of this in a 997 DFI engine. However, this engine doesn't differ in its fundamentals from other DFI engines - it still uses a crankcase re-breather with an oil separator, it still has fuel injectd directly into the cylinders, the inlet valves and ports aren't washed or cooled by incoming fuel. So why should this engine be any different to other DFI engines? Carbon build-up will happen, what we don't know is how much and how quickly. What we also don't know is the effect on power outputs.

Yes, I agree that we don't have all the information we need yet. However, that doesn't mean the engines don't suffer from carbon build-up, just like all DFIs and Diesels!!

Ian

I have seen no evidence anywhere in the world that suggests Porsche (or anyone else) has solved a problem that has eluded several manufacturers for yonks! Therefore, I expect Porsche DFI engines to behave the same way. By how much? I dunno either, hence my applauding Ian_UK1's offer and positively encouraging you to match it. Given your higher mileage, your own input would go a long way towards helping us all to understand this issue. If you both did this, even better!

Enjoy your weekend. Cordial saludos to all of you contributing positively to this thread.

Edited by bcnrml on Saturday 13th November 23:50

[drmark]

Por favour, no patronicar.

[nelly997s]

bcnrml said:

Martian O said:

Wills2 said:

Martian O said:

All I was stating is that previous Porsche engines generally haven't been as bomb-proof as we would've hoped or expected. Agreed, I think it's too early to write-off the DFI engine at the moment, but on basing it on previous Porsche designs, I am holding my breath regarding DFI cokeing issues.....

Edited by Martian O on Wednesday 10th November 22:46

Why when you have a GT1 block?

For when/if I consider a 997.2 Turbo!

Sounds like someone doing his/her research without blinkers or rose tinted specs on.

The point of a test before buying a used one is spot on - and a dyno alone wouldn't be enough. I say get a camera down there as some of the independents on here recommend.

Remarkable isn't it, that porker engines should now come with the results of biopsies to give owners better peace of mind than the wonderful 111 point check?

Dont forget Alusil
isnt that what bmw tried to use?
they dont look down the bores on a 111 point check either!

[jon-]

This could be quite a little scoop for PH.

I'm sure the 'old' PH would have welcomed the traffic, I'm not sure the 'new' PH will want to get involved and potentially ps off Porsche.

Watching with great interest.

[shoestring7]

Its an interesting case: DFI offers potential power and economy benefits, but my sense is that the issues with carbonising haven't yet been resolved.

I have to declare previous experience with an Audi A2 FSI (also direct injection) which suffered from endless running problems until an old technician suggested trying a decoke. More details of that experience here if anyone's interested: http://thecarlistblog.blogspot.com/2007/02/let-me-...

SS7

[Ian_UK1]

My car is going to my local Porsche indie in Manchester on Thursday to have the inlet valves inspected by borescope. Unfortunately, the borescope they have can't 'capture' digital images from its screen but I will do my best to photograph the images produced.

So, the answers you're waiting for regards carbonising issues will be published on here on Friday, barring any work issues preventing me from keeping the appointment with the indie. If I have to cancel for any reason, I will rearrange ASAP.

It would also be good if anyone with a higher mileage car than mine could also do the same so we can see how any effects vary with time and miles.

According to my indie, it's only a 10-15 minute job. Intake trunking off, push the throttle plate open, feed borescope down to inlet valves and take pictures.

Ian

[bcnrml]

Nelly997s, Jon and Shoestring, I agree and am also glad you've posted. If we can get pictures with different mileages and approximate types of use, this may be worth a sticky.

I do think PH wouldn't be bothered about hacking off Porsche, after all, if members provide evidence, how can Porsche get upset?

The only people who'll likely be upset are people like drmark. In his case, I am surprised that a self-confessed rocket scientist (astrophysics?) and porker nut seems keen to disparage discussion that may lead to an empirical exercise of benefit to pretty much all on here. Still, he's an interesting variation of my experience of the world of science, I guess.

Edited to add more support for Ian_UK1.

And I do hope the indies on here are watching this thread.

---

For the record, drmark, I'll be ignoring your posts henceforth. Our first encounter was when you dived into one of my earlier threads on Porsche's waning financial performance with rubbish data. Between then and your sanctimonious finger waving at RDMcG in his thread about a Clarkson article and The Times' paywall, you've provided plenty of evidence to support my decision. So enjoy PH and have one of these from me and another of these with plenty of mirth.

Edited by bcnrml on Monday 15th November 11:34

[drmark]

Phew! Mind you I can't help myself - I just have to dive in when I see patronising bullst posing as intellectual debate. IMO of course. Or maybe your lengthy diatribes on everything from the future of Porsche (not so gloomy after all!) to carbon build up on valves reflects your love of the sound of your own voice (metaphorically speaking, naturally). Either way I am happy to be sent out the class and miss out on future pearls.

[cragswinter]

Bcnrml:
I love your posts, in fact if I see that you were the last poster on a thread I always look as it's generally going to be a good read!
However you do come across on here as the man that runs around in a panic shouting "don't panic!" (I don't mean to cause offence, its very hard to judge a character by their writings but a certain image does get presented when we write on these things).
I'm not entirely sure what drmark has done to offend (I can't remember anything in particular on the threads you mention) but it didn't sound too bad on this thread anyway.
I think this is a very important thread (or could have the potential to be), dfi engines it would appear do have issues that people would need to know about. Let's try & keep the sniping out of the thread, believe me if this was 911uk the mods would be in already.
Having done a bit of investigating re the Audi engines (purely out of interest, I've never owned a direct injection petrol engine) it would appear that there is a problem there, not that this is solely a porsche problem, indeed unlike Mitsubishi & Audi there is yet to be a recorded problem.
If however there is a problem then it's hardly a fault of Porsche? Who makes these systems? Bosche?
If a dfi engine does need de-coking on a regular basis then this is surely a manufacture wide issue, & needs to be accounted for within the normal service & maintenance routine of all manufacturers?
Let's be honest if there is a problem (& it's not yet established if there is) what would be a suitable solution? Every 24000 miles an engine needs to be scoped & checked & noted in a vehicles service history? What if the car does need de-coked? Who is going to be likely to pay for that sort of treatment if they aren't aware in normal driving that the problem exists? It may be worth doing on a £60000 sports car but what if your £6000 runaround needs doing?
So if it's not to be part of the service schedule then the only avenue left would be to check within the mot. Now I'm pretty sure there's going to be a lot of people who can't afford to keep their cars on the road if that were the case.
I think it's terrific if people within the forum are willing to investigat their own cars for the good of the thread, I'm just not sure what it will acieve? Apart from more expensive servicing costs!
Forgive my memory but I can't quite remember the reasons behind why this was happening in audis? I may be wide of the mark but didn't it have something to do with short journeys or the car running in it's warm up mode for the majority of the time?
If so can a manufacturer be blamed for how a customer uses their product?
If by some miracle the manufacturers did find this to be a problem could they not simply do as BMW does & make a cold running engine reduce the service indicator accordingly, or even put some small print in the manual stating that performance may be reduced if a car is not properly warmed up in it's journey?
Craig

[Ian_UK1]

cragswinter said:

Bcnrml:
I love your posts, in fact if I see that you were the last poster on a thread I always look as it's generally going to be a good read!
However you do come across on here as the man that runs around in a panic shouting "don't panic!" (I don't mean to cause offence, its very hard to judge a character by their writings but a certain image does get presented when we write on these things).
I'm not entirely sure what drmark has done to offend (I can't remember anything in particular on the threads you mention) but it didn't sound too bad on this thread anyway.
I think this is a very important thread (or could have the potential to be), dfi engines it would appear do have issues that people would need to know about. Let's try & keep the sniping out of the thread, believe me if this was 911uk the mods would be in already.
Having done a bit of investigating re the Audi engines (purely out of interest, I've never owned a direct injection petrol engine) it would appear that there is a problem there, not that this is solely a porsche problem, indeed unlike Mitsubishi & Audi there is yet to be a recorded problem.
If however there is a problem then it's hardly a fault of Porsche? Who makes these systems? Bosche?
If a dfi engine does need de-coking on a regular basis then this is surely a manufacture wide issue, & needs to be accounted for within the normal service & maintenance routine of all manufacturers?
Let's be honest if there is a problem (& it's not yet established if there is) what would be a suitable solution? Every 24000 miles an engine needs to be scoped & checked & noted in a vehicles service history? What if the car does need de-coked? Who is going to be likely to pay for that sort of treatment if they aren't aware in normal driving that the problem exists? It may be worth doing on a £60000 sports car but what if your £6000 runaround needs doing?
So if it's not to be part of the service schedule then the only avenue left would be to check within the mot. Now I'm pretty sure there's going to be a lot of people who can't afford to keep their cars on the road if that were the case.
I think it's terrific if people within the forum are willing to investigat their own cars for the good of the thread, I'm just not sure what it will acieve? Apart from more expensive servicing costs!
Forgive my memory but I can't quite remember the reasons behind why this was happening in audis? I may be wide of the mark but didn't it have something to do with short journeys or the car running in it's warm up mode for the majority of the time?
If so can a manufacturer be blamed for how a customer uses their product?
If by some miracle the manufacturers did find this to be a problem could they not simply do as BMW does & make a cold running engine reduce the service indicator accordingly, or even put some small print in the manual stating that performance may be reduced if a car is not properly warmed up in it's journey?
Craig

Unfortunately, the carbonising issues most DFI engines and Diesels suffer from isn't fundamentally down to servicing schedules or driving style (although they might make a small amount of difference). The problem is that oil vapour, on hitting very hot metal, immediately burns and bakes itself on there as a carbon deposit. The mechanism for this to inevitably happen to a DFI engine's inlet valves is present in every DFI motor due to its crankcase breather system (required to meet even the most basic of emmssions requirements). The basic mechanism is explained in my first post on this thread.

Ian

[jon-]

Ian_UK1 said:

My car is going to my local Porsche indie in Manchester on Thursday to have the inlet valves inspected by borescope.

So, the answers you're waiting for regards carbonising issues will be published on here on Friday, barring any work issues preventing me from keeping the appointment with the indie.

Legend. Can't wait until Friday.

[cragswinter]

Thanks ian,
the point I made about servicing was not that it would get rid of the problem merely that it would flag up when the problem became an issue.
Now, with reguards to the breather pipe that circulates the mist of oil that (from what I read in the past) seems to be the crux of the problem does the engine recitculate this air at all times?

[Ian_UK1]

cragswinter said:

Thanks ian,
does the engine recitculate this air at all times?

Can't be certain on this but logic would say yes. There is always a small amount of blow-by going past the piston rings so there will always be additional gases that need to be removed from the crankcase. The oil gets into the system due to all the moving parts in the crankcase atomising it and throwing it everywhere - so it gets sucked into the rebreather system with the blow-by gases. An oil separator that uses the same vortex/cyclone technology that you see in Dyson vacuum cleaners does the job of removing the oil from the gases, but it's not perfect by any means. Hence the oil mist that sticks to the valves (but doesn't in conventional [non-DFI] fuel-injection engines as it is washed off by the incoming fuel).

Edited by Ian_UK1 on Monday 15th November 16:23

[Wills2]

Ian_UK1 said:

My car is going to my local Porsche indie in Manchester on Thursday to have the inlet valves inspected by borescope. Unfortunately, the borescope they have can't 'capture' digital images from its screen but I will do my best to photograph the images produced.

So, the answers you're waiting for regards carbonising issues will be published on here on Friday, barring any work issues preventing me from keeping the appointment with the indie. If I have to cancel for any reason, I will rearrange ASAP.

It would also be good if anyone with a higher mileage car than mine could also do the same so we can see how any effects vary with time and miles.

Ian

Ian I have a 33k mile gen2 and would be willing to look at getting this done.

However I'm a bit of a girl when it comes to going outside the dealer network with my car whilst it's under warranty. (I'm not impugning your indie or any other indie) but I would hate the thought of something unrelated going wrong and the OPC blame the fact that it's been touched by someone else for it.

So I'm going to call my OPC and ask them to do it as surely they have a borescope? Their answer might be quite interesting!

Edited by Wills2 on Monday 15th November 18:19

[bcnrml]

cragswinter said:

Bcnrml:
I love your posts, in fact if I see that you were the last poster on a thread I always look as it's generally going to be a good read!

Thanks. Here’s hoping I continue to entertain (whilst making some needed changes to the quality of content and levels of courtesy on PH).

cragswinter said:

However you do come across on here as the man that runs around in a panic shouting "don't panic!" (I don't mean to cause offence, its very hard to judge a character by their writings but a certain image does get presented when we write on these things).

No offence taken. My written style is mostly matter of fact, sometimes mocking of some on here, especially so when there’s an opportunity to see them hoist by their own petards. Drmark fits the bill nicely. He knows why, and if he doesn’t, he can do what others before him have had to do – reflect on the available evidence, be silent, or have a public argument with himself (supported by any/every other apologist on here who has now been proven wrong).
He hasn’t offended me (as I don’t get offended by ill-mannered ignorance. I merely use their content to wind them up even more). His posts devalue this thread whilst contributing little (if anything) of value. So there we have it.

Yes, I agree on the importance of this thread, hence my posts encouraging Wills2 and Ian_UK1 (and any other indies capable of helping). I’m pleased Wills2 is getting an OPC to take a look (though if I were him, I’d make watch the process – call me cynical if you wish).

I thought my posts were clear that it is likely as much a problem for all running DFI technology. Anyone saying this is not a problem for Porsche is deluding himself, and this is supported by the very points you make. My own theory (maybe hope) is that Porsche (and some others in the premium segment) are using the DFI as an interim measure until they can find a better route to lower emissions. VW maybe don’t care much given the financials you quote.

I agree that it’s good some people here are willing to help others, hence my liking this forum.

The scopes will hopefully help by encouraging owners to persuade Porsche to do something about it (I won’t hold my breath though). Instead, I expect that the good indies will find remedies that are cost effective, making my naïve hope (as expressed in Ian-UK1’s original thread) a reality. Everyone benefits in such a scenario, and that includes Porsche and the OPC network. Even the apologists should be happy.

Edited by bcnrml on Monday 15th November 22:48

[GT3ZZZ]

Bump!

So what's the story, carbon or not?? We need to know

[Martian O]

I'm sure Ian will post up his findings as soon as.............