997.2 Oil Consumption
08-29-2011, 05:52 AM
#211
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But I'll mention it to my secretary anyway.More important is that last note was done in my head while trying to deal intermittently with some stuff for Cindy. The mileage in the manual is 388, not 322. That's what happens when you try mult-ithreading with too shallow a stack, but never mind that.
It does explain one thing that niggled at me after I wrote that. The car will go further than 322 miles in the 'expressway' travel the manual talks about. I was wondering why they used the mixed or 'combined' fuel economy for their example. If they did the example in the English system at all, they were thinking of the 388 miles which is about what a 997.2 gets from a full tank in highway driving. (At 25 mpg, that's 15.5 gallons.) Yeah, maybe.
It seems more likely the engineers were asked about it by the technical writer tasked with adding that explanation of sudden drops in the oil reading and -- answering in German and the metric system of course -- they estimated how fast the reading could drop in... "Oh, say a thousand kilometers? "Ja! Vielleicht einem Liter und ein halb!" and the tech writer duly noted that for translation into quarts and miles.
Of such casual queries are committee meetings built.
Gary
08-29-2011, 11:52 AM
#212
Race Director
You woo a girl, burn some midnight oil together, and next thing you know...
Seriously, you don't own one, so I can understand your overlooking the fact that 322 miles is essentially one tankful of fast driving. That is, the distance you'd travel to your first fuel stop if you went somewhere on the 'expressways' as Porsche describes them. The "check range" light goes on with a variable amount of fuel remaining depending on your driving style, but roughly it happens when you've burned 14 to 15 gallons. 322 miles whenis effectively the distance from full tank to warning message in that sort of driving.Now we need to read the text to understand that datum.
In the chapter on Engine Oil it says that if you've been driving around town
Possibly they added that sentence in later versions of the owner's manual, but it would be the same for your older car even if they left out that warning from the manual. As I said in June:
So far as I know, the routine consumption that Porsche (and I) consider 'reasonable' is one quart per 600 miles. I've been hearing automotive engineers speak of one quart per 600 or one quart per 1000 or similar numbers all my life. And that's a pretty long time. From the examples others have quoted from Mercedes and Toyota, I suspect it has become an industry standard in some official or quasi-official way.
Oil is a consumable. We have to live with that and only care about sudden changes in comsumption. As when you change operating conditions. Just last week, I said:
Porsche even went so far as to give an example of the most common way to benignly make the oil reading drop from the top bar to the "check oil level" in a single tankful.
Even allowing for your lack of respect for Porsche, I think you're giving too much weight to a paragraph in a manual that is not translated with the fluency one could wish. You should instead take the word of the professional engineers, including me, that own one. The 997 is a good car. When you decide to make the jump, you won't regret it. You too, TBrom.
Gary
Seriously, you don't own one, so I can understand your overlooking the fact that 322 miles is essentially one tankful of fast driving. That is, the distance you'd travel to your first fuel stop if you went somewhere on the 'expressways' as Porsche describes them. The "check range" light goes on with a variable amount of fuel remaining depending on your driving style, but roughly it happens when you've burned 14 to 15 gallons. 322 miles whenis effectively the distance from full tank to warning message in that sort of driving.Now we need to read the text to understand that datum.
In the chapter on Engine Oil it says that if you've been driving around town
Possibly they added that sentence in later versions of the owner's manual, but it would be the same for your older car even if they left out that warning from the manual. As I said in June:
So far as I know, the routine consumption that Porsche (and I) consider 'reasonable' is one quart per 600 miles. I've been hearing automotive engineers speak of one quart per 600 or one quart per 1000 or similar numbers all my life. And that's a pretty long time. From the examples others have quoted from Mercedes and Toyota, I suspect it has become an industry standard in some official or quasi-official way.
Oil is a consumable. We have to live with that and only care about sudden changes in comsumption. As when you change operating conditions. Just last week, I said:
Porsche even went so far as to give an example of the most common way to benignly make the oil reading drop from the top bar to the "check oil level" in a single tankful.
Even allowing for your lack of respect for Porsche, I think you're giving too much weight to a paragraph in a manual that is not translated with the fluency one could wish. You should instead take the word of the professional engineers, including me, that own one. The 997 is a good car. When you decide to make the jump, you won't regret it. You too, TBrom.
Gary
You are confusing yourself.
For one, 1 quart of oil per tankful is shameful. That is simply unacceptable for a high end sports car without some ridiculously powerful engine.
2nd, the condensation/fuel argument is fine, but that has absolutely no bearing on the fact that Porsche considers it normal for a car to consume 1 quart per 388 miles. Yes, it can explain the appearance of oil loss, but it doesn't change their oil consumption standards.
I'm not sure why you stick with the 1 quart per 600 mile thing. The manual clearly says otherwise. I didn't make it up.
There is no translation issue. They specifically and clearly state that engine oil consumption can be up to 1.6 quarts per 622 miles. Its plain as day. I don't know how much more clear it can be.
You act as though oil consumption at that level is harmless...it isn't. Once again (for about the third or fourth time), this would lead to less power, a higher likelihood of detonation, and shorter catalytic converter life. You have said nothing to refute this.
I will never take the word of an engineer that thinks his car sometimes sticks after being parked because of excess tire shine. What is your engineering degree in btw?
But, I do agree the 997 is a good car...but you better believe I would raise hell or dump a car that burns that much oil.
Over a 100k lifespan, that would be nearly 260 quarts of oil. I guess the bonus is that you never have to change the oil since it doesn't stay in the crankcase long enough to need changing.
08-29-2011, 12:36 PM
#213
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To Gary on whether I'll enjoy a 997.2 - you bet I will.
To Quadcammer, you bet I won't if it burns 1 quart in 388 miles - you bet I would go right on to the next one for sale by owner till I found one that consumes what I would consider "acceptable" oil consumption.
What possible difference will it make if you car starts using a little more oil than 1 quart every 388 miles - not much and is that indicative of a "problem" - damn who could tell. What you will be looking for with high oil consumption, and I believe that 1 quart in 500 miles is too much, would it be smoking? There are other "signs" of engine problmes other than oil consumption. However, as Quad mentions with that much oil consumption there will be things happening to that car because of high consumption other than just adding oil between changes.
I'm not sure what the point is of all this but I would tend to think that something was wrong with my Porsche engine if it burned that much oil - and if there wasn't right away - what would be the cumulative effect over 5 years of oil consumption at that "high" rate - man, it just couldn't be good. There are other things to worry about with these engines - like how would you measure valve guide wear if your car was using that much oil - wouldn't it smoke? Wouldn't the smoke be blueish - well hell if it was burning 1 quart every 388 miles I'd think you'd see some blue smoke right away? Wouldn't you? At what point would you see it in the exhaust? Damn it's hard to fathom how one would even notice premature valve guide wear if their car burned that much oil from new - right?
There are other things we can look to to find a problem -well what would they be - catalytic converters going bad - what's acceptable wear there? All I'll say is that when you buy a new 997.2 wouldn't one of the questions of that owner be how much oil are you using and just hope he tells you the truth.....and I wonder if he/she would. It's a bit of a test. I am watching things like this carefully just to see if those that use that much oil actually develop problems sooner than others. That's really the other side of this conversation.
We need real data from those owners that continue to have high oil consumption over the duration of ownership of say 5 years minimum with 50k miles to see if other issues develop that would be attibutable to oil consumption of 1 quart every 400 miles or 600 miles - either one of those would bother me. But real data on repairs would be paramount to coming up with some quantitative indicators based or associated with oil consumption I'd think.
It's all fine and good to talk about oil consumption on cars with 1000 miles on them and what is the real "break in" period and how it starts improving at say 15,000 miles but what if it doesn't - what's in store for that owner with 5 years and 50k miles??? That's what everyone should be worried about and I'm sure that's exactly what folks are worried about. Many owners of 911s don't all have tons of fun bucks and don't care if they use a case of oil between 2 oil changes. There are many that just don't drive their cars much for various reasons but I would bet some of those reasons are worry over the high price of top end freshening!
You can damn sure believe that the guy with the 996 or 997 that has an IMS bearing failure and the subsequent engine blow finds no consellation whatsoever with the idea that only 5% of Porsches have this happen! Especially if his warranty is out and he bought his "dream car" used at 50k miiles from an individual and Porsche AG has never heard of this guy - has no previous "dealer history" and it's just tough luck - no support from Porsche! Believe me that would suck so bad and some have no idea that this could even happen - have never read the "tech" articles about this. It jsut catches them - boy you talk about a bummer! Buy a Boxster for 15k and the IMS thing hits you and your dealer says - yeah, we can put a new engine in for 15 to 17k - how bout that!
So when those that read and worry bout such things as indicators of pre mature valve guide wear it's no wonder that oil consumption of 1 quart in 500 miles might just make them a little nervous or cautious - it surely would me. Heck these new DFI engines are so new that there really isn't a lot of long term data in on "issues" of concern but to me oil usage of that amount would make me concerned. Concerned enough to take every precaution that I don't buy one that uses oil like that!
Nuff said....cause I really do want a 997.2. Waiting and watching and listening and reading till the time comes for me to buy!
Thanks to all
To Quadcammer, you bet I won't if it burns 1 quart in 388 miles - you bet I would go right on to the next one for sale by owner till I found one that consumes what I would consider "acceptable" oil consumption.
What possible difference will it make if you car starts using a little more oil than 1 quart every 388 miles - not much and is that indicative of a "problem" - damn who could tell. What you will be looking for with high oil consumption, and I believe that 1 quart in 500 miles is too much, would it be smoking? There are other "signs" of engine problmes other than oil consumption. However, as Quad mentions with that much oil consumption there will be things happening to that car because of high consumption other than just adding oil between changes.
I'm not sure what the point is of all this but I would tend to think that something was wrong with my Porsche engine if it burned that much oil - and if there wasn't right away - what would be the cumulative effect over 5 years of oil consumption at that "high" rate - man, it just couldn't be good. There are other things to worry about with these engines - like how would you measure valve guide wear if your car was using that much oil - wouldn't it smoke? Wouldn't the smoke be blueish - well hell if it was burning 1 quart every 388 miles I'd think you'd see some blue smoke right away? Wouldn't you? At what point would you see it in the exhaust? Damn it's hard to fathom how one would even notice premature valve guide wear if their car burned that much oil from new - right?
There are other things we can look to to find a problem -well what would they be - catalytic converters going bad - what's acceptable wear there? All I'll say is that when you buy a new 997.2 wouldn't one of the questions of that owner be how much oil are you using and just hope he tells you the truth.....and I wonder if he/she would. It's a bit of a test. I am watching things like this carefully just to see if those that use that much oil actually develop problems sooner than others. That's really the other side of this conversation.
We need real data from those owners that continue to have high oil consumption over the duration of ownership of say 5 years minimum with 50k miles to see if other issues develop that would be attibutable to oil consumption of 1 quart every 400 miles or 600 miles - either one of those would bother me. But real data on repairs would be paramount to coming up with some quantitative indicators based or associated with oil consumption I'd think.
It's all fine and good to talk about oil consumption on cars with 1000 miles on them and what is the real "break in" period and how it starts improving at say 15,000 miles but what if it doesn't - what's in store for that owner with 5 years and 50k miles??? That's what everyone should be worried about and I'm sure that's exactly what folks are worried about. Many owners of 911s don't all have tons of fun bucks and don't care if they use a case of oil between 2 oil changes. There are many that just don't drive their cars much for various reasons but I would bet some of those reasons are worry over the high price of top end freshening!
You can damn sure believe that the guy with the 996 or 997 that has an IMS bearing failure and the subsequent engine blow finds no consellation whatsoever with the idea that only 5% of Porsches have this happen! Especially if his warranty is out and he bought his "dream car" used at 50k miiles from an individual and Porsche AG has never heard of this guy - has no previous "dealer history" and it's just tough luck - no support from Porsche! Believe me that would suck so bad and some have no idea that this could even happen - have never read the "tech" articles about this. It jsut catches them - boy you talk about a bummer! Buy a Boxster for 15k and the IMS thing hits you and your dealer says - yeah, we can put a new engine in for 15 to 17k - how bout that!
So when those that read and worry bout such things as indicators of pre mature valve guide wear it's no wonder that oil consumption of 1 quart in 500 miles might just make them a little nervous or cautious - it surely would me. Heck these new DFI engines are so new that there really isn't a lot of long term data in on "issues" of concern but to me oil usage of that amount would make me concerned. Concerned enough to take every precaution that I don't buy one that uses oil like that!
Nuff said....cause I really do want a 997.2. Waiting and watching and listening and reading till the time comes for me to buy!
Thanks to all
08-29-2011, 01:11 PM
#214
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I believe Edgy01 997.1 burns about a quart / 1,000 and has since he picked up the car new in 2006. He might be able to provide some insight on any collateral issues associated with the oil consumption.
For a random unscientific data point, my 2006 uses less than a quart per 5,000. So for me if it were to burn more oil, something else is wrong.
997.2 are a different animal with the DFI.
For a random unscientific data point, my 2006 uses less than a quart per 5,000. So for me if it were to burn more oil, something else is wrong.
997.2 are a different animal with the DFI.
08-29-2011, 05:11 PM
#215
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Heh heh. Yeah, right.
I didn't know we had a standard these days. Have you considered publishing that? I'm sure your views that 100hp/liter is Camry like and one quart per tank is shameful would interest the engineering community. I can give you a link for e-publishing. A marketing tip. Your views probably would sell better in a community that has your own car. Trying to convince the owners of a different sports car is tougher. Maybe try the air-cooled forum?
You're the one boring me by missing the point. I didn't make any argument at all. I just quoted what Porsche says that explains why your oil consumption can be "up to" one quart per tankful.
Again, you should seriously consider publication. We've been eagerly awaiting someone to correct our misconceptions.
Gary
2nd, the condensation/fuel argument is fine, but that has absolutely no bearing on the fact that Porsche considers it normal for a car to consume 1 quart per 388 miles. Yes, it can explain the appearance of oil loss, but it doesn't change their oil consumption standards.
I'm not sure why you stick with the 1 quart per 600 mile thing. The manual clearly says otherwise. I didn't make it up.
I'm not sure why you stick with the 1 quart per 600 mile thing. The manual clearly says otherwise. I didn't make it up.
Gary
08-29-2011, 05:46 PM
#216
Race Director
Heh heh. Yeah, right.
I didn't know we had a standard these days. Have you considered publishing that? I'm sure your views that 100hp/liter is Camry like and one quart per tank is shameful would interest the engineering community. I can give you a link for e-publishing. A marketing tip. Your views probably would sell better in a community that has your own car. Trying to convince the owners of a different sports car is tougher. Maybe try the air-cooled forum?
You're the one boring me by missing the point. I didn't make any argument at all. I just quoted what Porsche says that explains why your oil consumption can be "up to" one quart per tankful.
Again, you should seriously consider publication. We've been eagerly awaiting someone to correct our misconceptions.
Gary
I didn't know we had a standard these days. Have you considered publishing that? I'm sure your views that 100hp/liter is Camry like and one quart per tank is shameful would interest the engineering community. I can give you a link for e-publishing. A marketing tip. Your views probably would sell better in a community that has your own car. Trying to convince the owners of a different sports car is tougher. Maybe try the air-cooled forum?
You're the one boring me by missing the point. I didn't make any argument at all. I just quoted what Porsche says that explains why your oil consumption can be "up to" one quart per tankful.
Again, you should seriously consider publication. We've been eagerly awaiting someone to correct our misconceptions.
Gary
What you quoted explains why the level on the gauge may drop quickly.
It doesn't explain why porsche says that consumption of oil (not fuel or condensate) is up to 1.6 quarts per 622 miles. Furthermore, as an engineer (haha), you should understand that additional fluid would RAISE the overall level, so boiling that additional fuel or water out of the oil results in tada, the level you started with. I mean christ, where did you go to school.
My viewpoint is supported by manufacturers from ford to gm to toyota to bmw, to mercedes etc etc. None have such lousy standards.
And please let me know where you got your engineering degree, because it doesn't seem to be worth the paper its printed on.
You get your views on the stickiness of tire shine published yet? What a joke.
08-29-2011, 07:35 PM
#217
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@Gary, Whether or not the oil consumption is within engineering standards used as Porsche is not really the point here, their *standard oil consumption* standard hasn't changed from .1 to .2, while clearly the oil consumption has increased due to new design. I just did a 1200 miles road trip and did NOT lose a single bar of oil in my .1 C4S, and many more have reported the same.
So, I guess we can basically conclude that 997.2 Oil consumption is significantly higher amongst Rennlisters anecdotal reporting here... that's all we can conclude (how statistically significant that is - who knows?), WHILE it is STILL within the limits Porsche claims in their manual (which is probably to cover them against lawsuits).
Whether or not the higher oil consumption in 997.2 causes long-term engine issues or other failures remains to be seen also...
So, if you buy a 997.2, you might have higher oil consumption than 997.1... that's all!
So, I guess we can basically conclude that 997.2 Oil consumption is significantly higher amongst Rennlisters anecdotal reporting here... that's all we can conclude (how statistically significant that is - who knows?), WHILE it is STILL within the limits Porsche claims in their manual (which is probably to cover them against lawsuits).
Whether or not the higher oil consumption in 997.2 causes long-term engine issues or other failures remains to be seen also...
So, if you buy a 997.2, you might have higher oil consumption than 997.1... that's all!
08-29-2011, 07:48 PM
#218
Race Director
08-29-2011, 09:36 PM
#219
Intermediate
I am unsure if I am referencing this correctly, but I started a new poll in 997 forum to record oil consumption during FIRST 5000 miles.
Thread link: https://rennlist.com/forums/997-foru...000-miles.html
Thread link: https://rennlist.com/forums/997-foru...000-miles.html
08-29-2011, 10:01 PM
#220
Nordschleife Master
08-30-2011, 02:55 PM
#221
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LOL!
I love that you and Mike BOTH only quoted a part of what I said and not the full statment (i.e. who knows "anecdotal" reporting here has any statistical meaning!).
I love that you and Mike BOTH only quoted a part of what I said and not the full statment (i.e. who knows "anecdotal" reporting here has any statistical meaning!).
Last edited by 911SLOW; 08-30-2011 at 04:13 PM. Reason: Only oil / no politics pls. : )
08-30-2011, 03:16 PM
#222
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This is exactly correct ADias - this is how it happens - but there are now wrong conclusions being made- there is no conclusive evidence that 997.2s are burning more oil than any previous Porsche models imho.
What has been going on here between Quad and Gsims is a discussion about what the Porsche manual allows not what is actually found. Gary is right on the money with his assertions that all this really means is that what you really need to focus on is not the maximum allowed but whether or not you have a car that has shown some sign out of the what is "normal" for your car range that you've noticed as you conitnuously monitor your own oil consumption in your 997.2. Not that there is any conclusive evidence that the 997.2 is actually burning more or less based on very loose empirical data gleaned from the tiny cross section we have here in this thread.
I will visit the other thread that Summit81 mentions just to see what's happening there.
This has been valuable in a lot of ways just to get a glimpse of how engineers might look at oil consumption and come up with maximum usage acceptable standards which apparently are just like Mercedes as another pointed out.
All very interesting to us "gear heads" and Porsche lovers.....
What has been going on here between Quad and Gsims is a discussion about what the Porsche manual allows not what is actually found. Gary is right on the money with his assertions that all this really means is that what you really need to focus on is not the maximum allowed but whether or not you have a car that has shown some sign out of the what is "normal" for your car range that you've noticed as you conitnuously monitor your own oil consumption in your 997.2. Not that there is any conclusive evidence that the 997.2 is actually burning more or less based on very loose empirical data gleaned from the tiny cross section we have here in this thread.
I will visit the other thread that Summit81 mentions just to see what's happening there.
This has been valuable in a lot of ways just to get a glimpse of how engineers might look at oil consumption and come up with maximum usage acceptable standards which apparently are just like Mercedes as another pointed out.
All very interesting to us "gear heads" and Porsche lovers.....
08-30-2011, 03:23 PM
#223
Race Director
C'mon, Alex. I was just trying to be economical with my quote. Your entire post is there for all to see, it's not as if anyone is trying to hide what you said in order to misconstrue it. I posted the bits I specifically disagreed with or wanted to comment on; mainly your use of the word clearly when nothing about this issue is clear.
Last edited by Mike in CA; 08-30-2011 at 04:28 PM.
08-30-2011, 05:33 PM
#225
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If you really care, I use my real name so you can always Google my resume.
Gary
Last edited by simsgw; 08-30-2011 at 06:40 PM. Reason: typo