Break in a 991
05-31-2014, 01:36 PM
#61
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By the way... This is not aimed at either Chuck or Zohan particularly... I'm just as intrigued to understand the science !
05-31-2014, 06:31 PM
#62
For Your Weekend Reading Enjoyment
My favorite comment so far is the one about this being a polarizing subject. Until recently I would have said that whether the user intends it or not this is a tactic favored on the left for getting people they disagree with to shut up. Because, you see, its your position that's polarizing, not mine! I get to do what I want, but you shut up because you are polarizing! And that's all true and good, but thanks to Alan Watts I've learned something a whole lot better.
As he would say, how do we know the bark is hard? It is only because our skin is soft. The spark that ignites combustion happens because there is positive, and negative. The engine runs because there is hot, and cold. There is no light, without darkness. Life has meaning, because of death. There can be no self without the other. To struggle against polarizing opposites is to struggle against the very nature of nature itself!
So, contrary to what some may think, I have no interest in having everyone think or be just like me- because I know that if that were to happen there would be no more me! Then what would be the point, for example, of writing outlandishly opinionated screeds when everyone reading it already holds the exact same outlandishly screedy opinionated opinions? None! Hell on earth! I'd put a bullet in my head, except for the fact then everyone else would too, because we're all the same, and I really can't see how things can get any more hellish than that!
So let's all raise a toast to Nature for being so goddamned polarizing!
Because of this I try hard to focus on getting the basic facts straight. That's hard enough, by the way. What people do with this basic knowledge, well that is their own business. My friend Hammer911, for example. We met and had a great time and continue to correspond, and I'm pretty sure he knows where I'm coming from so here goes. Hammer followed factory break-in with his 991. I've never gotten on his case, but at the same time I don't pull any punches in my posts just because I know he'll be reading. Because, see, its just fine with me! The way I look at it, we all buy these cars for our personal enjoyment- and boy, is he enjoying his car! Besides, I am on record as having stated I really don't think that following the factory baby-in is doing any real harm. Where I get going is when people whine about it, or act like its some kind of badge of honor, or…. ask if its really necessary… or get some basic facts wrong. Boy, do I love to correct basic errors of fact!
Like this polishing thing. Polishing is a very specific process in which abrasives of a specific size are ground against another material in a deliberately uniform manner designed to achieve a smoother surface. Now let me ask, does that sound anything like what happens anywhere in an engine? It would- if we poured polishing abrasives into the oil and cranked it around by hand a couple thousand times.
No, I take that back. Even then, even with hand cranking, because of things like cam lobes and crank geometries the forces exerted on the polishing abrasives would vary depending on the point in the cycle, meaning the polishing would not be uniform (which is the whole point of polishing!) so even then it would not work. Imagine how much worse the situation must be in an actual running engine, where the loads vary immensely and instead of uniform polishing abrasives there's a miss-mash of all kinds of stuff from bits of metal to corrosive acids doing the erosion more or less at random.
Besides, if this concept worked then the logical result would be that rather than engines wearing out they would just get better and better, increasingly smoother and more perfectly in spec, the more miles we put on them. Goofy, I know. But people actually believe this stuff. Which is fine, and as I've said, perfectly natural. Just don't try slinging such nonsense my way. I'll take the polar opposite of that one every time!
My favorite comment so far is the one about this being a polarizing subject. Until recently I would have said that whether the user intends it or not this is a tactic favored on the left for getting people they disagree with to shut up. Because, you see, its your position that's polarizing, not mine! I get to do what I want, but you shut up because you are polarizing! And that's all true and good, but thanks to Alan Watts I've learned something a whole lot better.
As he would say, how do we know the bark is hard? It is only because our skin is soft. The spark that ignites combustion happens because there is positive, and negative. The engine runs because there is hot, and cold. There is no light, without darkness. Life has meaning, because of death. There can be no self without the other. To struggle against polarizing opposites is to struggle against the very nature of nature itself!
So, contrary to what some may think, I have no interest in having everyone think or be just like me- because I know that if that were to happen there would be no more me! Then what would be the point, for example, of writing outlandishly opinionated screeds when everyone reading it already holds the exact same outlandishly screedy opinionated opinions? None! Hell on earth! I'd put a bullet in my head, except for the fact then everyone else would too, because we're all the same, and I really can't see how things can get any more hellish than that!
So let's all raise a toast to Nature for being so goddamned polarizing!
Because of this I try hard to focus on getting the basic facts straight. That's hard enough, by the way. What people do with this basic knowledge, well that is their own business. My friend Hammer911, for example. We met and had a great time and continue to correspond, and I'm pretty sure he knows where I'm coming from so here goes. Hammer followed factory break-in with his 991. I've never gotten on his case, but at the same time I don't pull any punches in my posts just because I know he'll be reading. Because, see, its just fine with me! The way I look at it, we all buy these cars for our personal enjoyment- and boy, is he enjoying his car! Besides, I am on record as having stated I really don't think that following the factory baby-in is doing any real harm. Where I get going is when people whine about it, or act like its some kind of badge of honor, or…. ask if its really necessary… or get some basic facts wrong. Boy, do I love to correct basic errors of fact!
Like this polishing thing. Polishing is a very specific process in which abrasives of a specific size are ground against another material in a deliberately uniform manner designed to achieve a smoother surface. Now let me ask, does that sound anything like what happens anywhere in an engine? It would- if we poured polishing abrasives into the oil and cranked it around by hand a couple thousand times.
No, I take that back. Even then, even with hand cranking, because of things like cam lobes and crank geometries the forces exerted on the polishing abrasives would vary depending on the point in the cycle, meaning the polishing would not be uniform (which is the whole point of polishing!) so even then it would not work. Imagine how much worse the situation must be in an actual running engine, where the loads vary immensely and instead of uniform polishing abrasives there's a miss-mash of all kinds of stuff from bits of metal to corrosive acids doing the erosion more or less at random.
Besides, if this concept worked then the logical result would be that rather than engines wearing out they would just get better and better, increasingly smoother and more perfectly in spec, the more miles we put on them. Goofy, I know. But people actually believe this stuff. Which is fine, and as I've said, perfectly natural. Just don't try slinging such nonsense my way. I'll take the polar opposite of that one every time!
05-31-2014, 07:00 PM
#63
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I have yet to get my very first P-car (delivery pushed up to July 25) but I have been following this thread a lot. My dealer told me that really, the porsche manual is old-fashioned and in need of an update. He claims that with these new technologies and with the fact that every Porsche gets on the dyno at the factory, you don't really need to break in the engine but for the first 200 miles or so. After that he said "...use the launch control all you want and drive it like you stole it..." He was more concerned about the Porsche brakes and the break-in for those. He said that the brakes can take upto 500 miles to "mate" (I think thats the word he used). Obviously this is just his opinion.
05-31-2014, 07:42 PM
#64
Rennlist Member
Wow... 3 paragraphs devoted to correcting the harmless use of a single word....
Substantiated by my 2 good ole English Dictionaries...
Polish (verb)
Def 1 ) To make smooth and glossy by rubbing
Def 2) To bring to a finished state
Sounds like the process i was describing.... And the use of abrasives would therefore be a means to an end, not a definition of the process
All I'm really interested in is understanding the science... And i appreciate this may have been discussed many times before but there are a lot of newbies on here like me who want to learn from people to help maximise their understanding and enjoyment...
Substantiated by my 2 good ole English Dictionaries...
Polish (verb)
Def 1 ) To make smooth and glossy by rubbing
Def 2) To bring to a finished state
Sounds like the process i was describing.... And the use of abrasives would therefore be a means to an end, not a definition of the process
All I'm really interested in is understanding the science... And i appreciate this may have been discussed many times before but there are a lot of newbies on here like me who want to learn from people to help maximise their understanding and enjoyment...
05-31-2014, 07:42 PM
#65
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Thread Starter
Some say that only random engines get dyno at the factory and your guy says that all these new cars get dyno...Does anyone know which one is fact?
05-31-2014, 07:55 PM
#67
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05-31-2014, 08:58 PM
#68
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This is easily tested in a engine lab as Porsche has done. Take two new engines and run side by side on with variations under 4k and the other all the way to redline for period of time flowed by dynamometer testing, oil analysis, and autopsy with microscope exam. The recommendations for brake in are based on this kind testing.
If you rub two pieces of sandpaper together they will become less abrasive.
Adjacent moving parts rubbing on each other will have in smoother contact surface. By smoother I means lower coefficient of friction. Breaking an engine slowly will result in the less random (less variation in movement range and force) where on moving parts. ie under 4000rpm.
Force of each combustion at low RPM is in fact higher then when engine is redlining. This because at lower RPM intake valve is open for sufficient period of time for pressures equalize resulting in more fuel air mixture in the cylinder. As RPMs go up the time intake and exhaust valves are open decreases and eventually engine reaches its maximum speed. Typically higher power is seen higher RPMs because higher RPM also results in more power strokes (with lower power per stroke) per minute. Variable geometry camshaft can partially correct this.
What Porsche has to gain by making the owner of a new 991 suffer for 2000 miles? The only think I can come up with: less repairs under warranty. BTW the warranty offered is significantly varied from one country to the other.
If you rub two pieces of sandpaper together they will become less abrasive.
Adjacent moving parts rubbing on each other will have in smoother contact surface. By smoother I means lower coefficient of friction. Breaking an engine slowly will result in the less random (less variation in movement range and force) where on moving parts. ie under 4000rpm.
Force of each combustion at low RPM is in fact higher then when engine is redlining. This because at lower RPM intake valve is open for sufficient period of time for pressures equalize resulting in more fuel air mixture in the cylinder. As RPMs go up the time intake and exhaust valves are open decreases and eventually engine reaches its maximum speed. Typically higher power is seen higher RPMs because higher RPM also results in more power strokes (with lower power per stroke) per minute. Variable geometry camshaft can partially correct this.
What Porsche has to gain by making the owner of a new 991 suffer for 2000 miles? The only think I can come up with: less repairs under warranty. BTW the warranty offered is significantly varied from one country to the other.
05-31-2014, 09:22 PM
#70
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Thread Starter
Has anyone been at the factory and ask the question about if all engines get dyno or not? I know on the old days cars were also road tested each and everyone of them...
05-31-2014, 09:27 PM
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All engines are NOT dyno'd. I/we don't need to know everything Porsche. We just need to know the right people who have the knowledge.
Rennlisters who have toured Porsche have reported that engine dyno testing is purely random.
05-31-2014, 09:49 PM
#73
For what it's worth I've been to the factory twice (997and 991 production) and each engine has a cold test. No fluids are in it and it's a quality check. On a few cars they'll take them out and drive them around town fairly aggressively for a more detailed QC. Every experienced Porsche mechanic will tell you to break it in the way you'd normally drive it - the science behind it is as others here have argued. My good friend takes it easy for the first 500 and then he's off. I've always followed the 2k break in. My view is that there are lots of systems working together and gradually bringing them to life will in all likelihood enhance the longevity of the underlying parts. That doesn't mean that my engine is going to perform like one that was broken in sooner. The only empirical evidence is that my friend (who's a PCA Instructor) has had valve seal leaks, I fortunately haven't had any issues on my cars, but clearly you can't draw a conclusion from that.
05-31-2014, 09:55 PM
#74
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Thread Starter
My thoughts exactly. The car is like an ecosystem composed from many interacting components, so the breaking in is NOT meant for the engine alone, but for all the moving components i.e transmission, brakes, tires and so on, making sure that all pieces work in harmony.
05-31-2014, 10:05 PM
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Ok... I'm sold... I will follow the porsche manual... sigh... I figure if I drive for the first 72 hours of ownership, I could make it to 2000 miles easy. I will take shifts with my best friend! 