mdrums

I believe it is the DFI that is causing the soot and possibly Porsche ECU tuning. My 2009 Cayenne also has more than normal soot on the exhaust tips and it is not buring any oil.

The ONLY time I do not have black soot all over the exhaust tips is when I do a DE. At a DE my car does not see under 4k rpm most of the weekend. The exhaust tips turn to a clean greyish white color.

Bijan

We know that DI engines run cooler because of fuel injection directly into cylinders vaporising and having a "refrigeration" effect. Hence less radiators than non DI engines.
This has to have a soot effect at warm up surely?

Wills

I've run 7000 miles in mine now from new and only had to put in 2/3 of a litre of oil and get no excessive soot.....hopefully those are good signs!

Oh and I ragged it from day one......

ask

Not to restart an old thread; but just wanted to say thank you to everyone here. :-) I got a ~4000 miles old 2009 C4S late last year and was a little alarmed when it needed 1.5 liter of oil after 2500 miles (despite the manual saying that's normal, it just seemed crazy).

Anyway, reassured that all is well after reading most of the 11 pages here. Like the original poster I don't care about the $8 for an occasional quart of oil; just wanted to make sure the car is happy.


p.s. No soot.

simsgw

And I'm just a graduate engineer who follows the same approach. With the same result I might add. We bought our C2S 997.2 at 11,000 miles and changed the oil around 18,000. (Too lazy to go look it up.) It's coming up on 25,000 and the next service. Still hasn't used a quart of oil in... what's that? 14,000 miles. Right now, it's half a quart low, but the service will take care of that.

Even if it were using a quart per tankful I would stick with Porsche's oil recommendation. Oils are part of the engine design these days. Not that somebody can't formulate a suitable oil, and not that I couldn't research the issues for myself to pick an alternative, but because I prefer to get paid for such a detailed technical investigation. And it has no hobby value when I'd end up with the same answer and merely add a couple of other candidate oils to the list. Why should I bother? They designed it with a specific Mobil 1 compound in mind, so I have no reason to waste my time. I just use what they spec'd.

Lacks originality I know, but I save my creativity for design work where it's needed.

Incidentally, someone said every person with a tech background they knew had recommended a 'break-in' of driving the car hard. Not everyone. I use conservative break-in procedures, as do most other engineers.

I also read the manual to learn how to check the oil, and with a dot two, the procedure does not involve letting the car sit for ten minutes or any other length of time with the engine off. I won't get into the technical design questions involved here, but don't follow your mechanic's advice or anyone else's advice. Read the bloody manual and do what it says, not what your buddy does on his '59 Speedster or your grandpa with his '89 Valiant or even somebody on a forum who got 200,000 miles out of his 993 doing it his way. Forget all of them. Follow the instructions in your owner's manual.

Well, assuming you want the right answer. You could always top it off with automatic transmission fluid once a week, just in case. But I plan to drive mine for a longgggg time, so I'm doing it the right way.

P.S. It is nice our example doesn't use significant amounts of oil, but the factors that consume oil vary with each unit that comes off the line. Up to the consumption level Porsche considers 'reasonable' I wouldn't worry about it. It's a bit more nuisance to add oil regularly, but not difficult. I bought a case of the right Mobil 1 when we got the car and it's still sitting there in the garage, but it wouldn't worry me to be using another quart regularly.

Gary

Quadcammer

you understand of course, that the owners manual is written by attorneys, not engineers.

Do you think something magical happens at exactly 1,000 miles?

mdrums

Do you have the stock exhaust on your car? If so then you will not notice the soot....(too much muffleing to go through). If you put on a more open exhaust you'll notice the exhaust tips getting black.

My 09 C2S now has 20k miles and a lot of those are at the track. the car is now consuming a lot less oil.

brendo

not sure i get your comment

Alan C.

Under normal driving I don't need to add any oil between 3000 - 4000 mile changes in combined city highway driving. A track weekend requires slightly less than 1/2 quart. Current milage is ~18000 mi.

Quadcammer

which one?

attorneys write the manual to avoid liability. Can't really tell people to get on the gas pedal hard for new owners. First guy does it, not familiar with the car, hits a tree, sues, etc.

As for the magic, I find the fact that the manual specified 1,000 miles or 2,000 miles or whatever as the "break-in" period ridiculous. For the most part, the only part of the engine that really needs to "break in" are the rings. The remainder of the parts may have a wear in period, but lets face it, if WOT and 6000rpm are enough to cause damage, then the engine was either not built correctly or there was some improper machining on the engine. Neither of these things are fixed by waiting 1,000 or 2,000 miles.

the break in mileage in the manual is simply liability coverage for the manufacturer.

Minok

I doubt that. The manual is way too legible and complex to be written by attorneys or technical writers. There are too many engineer fingerprints on it. Tech writers and attorney's had their input.. you can find it in places (like when you press the NAV button and have to punch through a disclaimer), but engineers and business folks determine the numbers on performance, fluid levels and consumption.

dansen

I think they compiled many sources to create an owner manual. Things like dealer services histories and customer complained, etc. And before the new version introduced, there is a process of prototypes. You see those spy shots cars everywhere, on snow, rain and city traffic. They are putting a lot of miles on those cars and study on them before they came up with 20,000m every oil change, etc. Of course they are always on the preservative side. Even though some owners still do their oil change every 3,000m. LOL

Quadcammer

I'm less talking about consumption (any engineer that says 1.6 quarts per 622 miles is acceptable should be fired), and more about break in rules.

Minok

This is why they have pre-production manuals and get them proof-read by many different people. So they don't claim that you need to change your oil every 20km (ie 20,000 meters).

If the design is such that 1.6 quarts per 622 miles is within the range of the design and was a trade off made to achieve other goals, I don't see why an engineer should be fired. Without knowing the whole story of the design, we cannot really comment about how stupid the acceptable but high (compared most other cars) oil consumption is.

Agreed, lawyers (and lots of finance folks) probably had some significant say in the break in rule... to keep folks from redlining the car off the lot all the way home and then coming back with issues of cylinder damage, etc.

Quadcammer

I guess my point is that the design is not as such.

No modern factory street engine should consume that much oil.

I think its an example of porsche covering their ***, instead of some inherent design strategy