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Old 13th March 2012, 20:04   #46
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Default Re: Factors Affecting Reliability

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Originally Posted by Aroy View Post
They design components for a more severe environment than the cars will experience. So the components last longer and failure rates practically non existent. Another plus point with Japanese design is that components and their placement are designed for ease of maintenance and not for compactness, ease of manufacture or performance.

The Merc 130D is a very good example of this "over engineering".

The "(Mahindra) Allwyn Nissan" is another.

IMHO, the Tata 407 is yet another example.
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Old 14th March 2012, 15:47   #47
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Default Re: Factors Affecting Reliability

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Originally Posted by C300 View Post
While I agree that the Japs have been manufacturing the cars predominantly for the export market, Germans have also been doing it for decades now.
I dont think there can be an excuse for unreliable cars given the customers in countries such as India are paying through their noses for German brands.
I am sure they must be testing the vehicles in our condition, if not then they are taking us for a ride.
Its not just India's case, its the same for every country when it comes to German / Italian or any european cars!
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Old 21st March 2012, 15:48   #48
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Default Re: Factors Affecting Reliability

Perhaps the fact/opinion that a vehicle has a huge upkeep adds to the snob value ...
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Old 27th June 2014, 20:53   #49
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Default Re: Reality check for VW: Lowers marketshare target for India

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Originally Posted by TheLizardKing View Post
Talking about ethics in the Indian automobile industry (excuse me for going slightly ), this thought came to me as I was driving home), what stops Maruti and the others from offering airbags in their cars? Is it ethics or is it the lax Indian safety laws? Does Maruti (and every other OEM) need laws to make them understand that selling death traps to their customers is just plain wrong?

Oh and guess which is the ONLY car manufacturer in India that now offers airbags as standard across all trims of its entry level car?
Fair point, and it's a point that I too have stressed on in various related threads. Maruti is no angel in the pruning department. Especially when it comes to safety. And it's probably worse to have inferior safety standards than an inferior gearbox.

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Originally Posted by Jeroen View Post
If you believe that, the future doesn't look very promising! Luckily, history has proven you wrong. Let me give a very simple example. Aviation: the number of components on and complexity of planes has risen sharply over the last decades. However, in that same time aviation safety has increased dramatically.

If you look at car statistics in a meaningful way you will find the same trend. Do you really think a T-Ford is more reliable then the latest Mercedes E class because it has fewer components?

Jeroen
Great point.

I too mentioned that keeping it simple is the key. Yes, DSG is the way forward, but not the way VW are going about it here. They should either give us a sorted DSG or just a manual gearbox. Not something that has a *ahem* reputation.

If not anything, issue official recalls and fix the problem.
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Old 27th June 2014, 20:56   #50
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Originally Posted by TheLizardKing View Post
Thank you for taking the time to type out that long post. I really appreciate it. So I get your point that a turbocharged engine is not simply a NA engine with a turbo thrown in. But here is my counterpoint. Consider two engines, one NA and the other TC, designed for exactly the same reliability. What about reliability in use?
  • A TC engine is more complex with a greater number of parts.
  • It needs special care while driving (e.g. the idling rule) that a NA engine does not.
  • It needs special maintenance that a NA engine does not. (I have never owned a turbo so I am making an intuitive guess here.)
So as a result of the above points, wouldn't a TC engine tend to fail more often than a NA one on the road?
.
See my earlier post. I do believe that in general reliability has improved and so has the complexity of engines. To your earlier point, adding components/increasing complexity tend to decrease reliability, at least in theory. The only way to increase reliability whilst also increasing complexity, is that the reliability of the various components has improved as well. And that has been happening. A practical example, an electronic fuel injection system is infinitely more complex than a carburetor. However, most electronic fuel systems are much more reliable than carburetor systems.

I own a 1986 Alfa Romeo Spider, which is equipped with a Bosch L-tronic injection system. It was one of the earlier Bosch electronic system. This very same Spider was also built with a carburetor. I'm intimately familiar with both system, having been on the Dutch Alfa Romeo Spider Technical Committee for many years and 10's of thousands of miles of rallying all over Europe. The electronic systems hardly ever give any problems. We were endlessly poking screwdrivers into the carburators and adjusting them, cleaning them etc.

I don't think a TC engine needs much special care. There is a whole thread on this forum about the idling rule and I've added my 2 cents there as well. In general modern TC don't require it at all. If the owner's manual doesn't state it, don't bother. Very few people actually read the manual, so there are very few people out there that have ever heard of the idle rule other than us nerds on this forum. Still, as I pointed out, the roads in India are not exactly littered with cars with blown up TCs. These days its largely a myth kept alive by well intended but not well informed car nerds.

So TC engines are really reliable and really need very little care, with the few exceptions, see your owners manual. Of course, for a NA or a TC engine goes you need to adhere to the standard operating procedures. If not, you could damage or break the thing, but that is not really a reliability issues I think.

TCs require very little to no maintenance.

So, from my point of view; all this extra complexity is a good thing. It makes engines more reliable, allows us to pack more punch into the same volume/weight, gives us less emissions etc. However, there is one downside. People that don't understand this new complexity tend to have issues with it. They call it less reliable, difficult to troubleshoot and so on. This forum is absolutely awash with threads on problems with modern engines and most of the advise offered is complete rubbish. Because people don't understand how to deal with this sort of stuff. It needs a different skill set/competence, a different set of tools, notably an OBD analyzer and very different diagnostic skills and insights.

So I don't think a TC engine fails more often then a NA engine. I think people perception is wrong, based on bias towards old technology and a lack of understanding new technology. What is not understood is often disliked and discredited.

There is probably one aspect of older engine technology that is better then modern engines. There is a general sense that old engines last longer then modern ones. That's totally different from reliability as such. Although I can't really say anything based on facts, I do believe there might be some element of truth in that. What remains to be seen is how relevant it is for the average car owner who trades his/her car for a new one after a couple of years or when it reaches 100 - 150K. Any car with any engine will get there. For me it is relevant because I tend to buy all my cars with at least 100K on them.


Quote:
Originally Posted by blacksport View Post
Probability addition:

P(EF or TF) = P(EF) + P(TF)

If you think I am wrong, you may want to explain the math. I would like to learn.
Have a look at this link which illustrates perfectly my point on how two reliable systems/components on their own function as a complete system.

http://www.eventhelix.com/realtimema...m#.U613LRZ-FFc

So first you need to understand how these two system affect each other, then you need to define how you measure the reliability. In the above case it is expressed as percentages.

The engine and TC are a serial system. If we take you figures it means both engine and TC have a reliability each of 99.999%. So according to this formula the reliability of the two is 99,998%. Hence my earlier statement that it is only a very small effect.

As a rule of thumb, reliability and or accuracy calculations depend heavily on the system configuration. The math is never a simple add/divide, but actually tends to involve "power to 2", 1/x and square roots in its most basic form. Or in case of a very simply model. Modeling these sort of systems, or rather much more complex system, say a nuclear power plant, and doing these sort of calculations is pretty much a science in itself. I'm not an expert by any means, but I find it very fascinating and if I can draw one conclusion is that very few people even understand the very basics. Its really down to statistics and generally people suck at that. That's how Casino's make a killing!

Jeroen

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Originally Posted by suhaas307 View Post
Great point.

I too mentioned that keeping it simple is the key. Yes, DSG is the way forward, but not the way VW are going about it here. They should either give us a sorted DSG or just a manual gearbox. Not something that has a *ahem* reputation.

If not anything, issue official recalls and fix the problem.
Just to bring my previous post a little more back to the original topic.

To my earlier points and previous posts. I don't think keeping it simple is the key perse. Keeping it reliable is the key and I hope I made it clear that those are different things and they don't necessarily conflict at all. Plenty of proof for that.

The DSG saga is probably one of the exceptions, or dud, as I mentioned in my earlier posts. I have had several VWs and Audi's with DSG, but those were the earlier models. Last one I drove was a 2008 Audi and that was the 3rd DSG company car I drove. Never gave me any problems, in fact I absolutely loved it, great auto box and for somebody like me who did close to 100.000 km a year an absolute God sent.

On a slightly more lighter note: The current DSG might be a bit of a wonky box. The DSG commercial is one of the best I've ever seen:




Jeroen

Last edited by noopster : 27th June 2014 at 21:38. Reason: Merging back to back posts
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Old 27th June 2014, 22:14   #51
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Default Re: Reality check for VW: Lowers marketshare target for India

Guys, pardon my ignorance but have the DSGs introduced recently in Polo and Vento TSI also started failing? Or we are talking about Jetta TDI AT here in contrast of unreliable DSG? Passat - they are not selling anymore AFAIK!
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Old 27th June 2014, 23:57   #52
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Default Re: Reality check for VW: Lowers marketshare target for India

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Originally Posted by blacksport View Post
You are just picking up phrases from my post to gain an upper hand. This is not a fight where one has to win. I am offering my perspective - of a person who like using these products. Which you are failing to see since you are busy trying to win a fight. Please read and understand what is being said before hitting that reply button.

For the record, I said "you may consider us", not "we are". As long as I am getting value from my car (in this case, the driving pleasure) I am okay with whatever quirks that come along with it. For those who are not like me, there are other tried-and-tested cars. If VW start making boring, old, tried-and-tested cars like most others, people like me would be left with nothing worthwhile.
I am sorry BS if you are hurt. My intentions were not that. Nothing against you personally. But then neither I may or must consider you a guinea pig nor you must consider yourself a guinea pig. There should be no guinea pigs. A new technology should only be realeased after all the bugs have been ironed out. I reiterate one more time what I said before that DSG needed some more research and working to make it bug-free. They should have perfected it before launching it big-time.

At least, do you agree with what I said in bold font above?
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Old 28th June 2014, 09:09   #53
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Default Re: Reality check for VW: Lowers marketshare target for India

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Originally Posted by Jeroen View Post
No it doesn't, sorry to say, you have no idea.
Jeroen
Quote:
Originally Posted by Jeroen View Post
The engine and TC are a serial system. If we take you figures it means both engine and TC have a reliability each of 99.999%. So according to this formula the reliability of the two is 99,998%. Hence my earlier statement that it is only a very small effect.
So you wrote all that to say that 1/10000 is in fact 99.999% reliability and 1/5000 is 99.998%. IN fact, it is 99.990% and 99.980%. Now the only point where I disagree with you is, you say that the reliability is only affected slightly. I think it is only a matter of perspective. The way I look at is, based on the above assumptions, for every NA engine that fails there would be two turbo engines that would be failing. And that tells something, doesn't it?
Quote:
actually tends to involve "power to 2", 1/x and square roots in its most basic form.
Come on, instead of saying that the formula has square roots and power to 2 (squares, right), and 1/x, where is the formula? Am sure we all went to school where they taught us squares, square roots and inverses, so it is not something we cannot understand. Why don't you post the formula than throwing jargon around.
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Originally Posted by pgsagar View Post
I am sorry BS if you are hurt. My intentions were not that. Nothing against you personally. But then neither I may or must consider you a guinea pig nor you must consider yourself a guinea pig. There should be no guinea pigs. A new technology should only be realeased after all the bugs have been ironed out. I reiterate one more time what I said before that DSG needed some more research and working to make it bug-free. They should have perfected it before launching it big-time.

At least, do you agree with what I said in bold font above?
No hurt, honest. I agree with what you have written in bold. Am not defending the company here. Am just defending my right to have access to these un-perfected technologies. When the Polo TSi came along, many BHPians jumped at it even though we all knew that the DSGs are unreliable. But yes, I agree that DSGs are a bit too unreliable than any new technology in the market.

I exit here.

Mod Note: Please take the discussion on probability and other things irrelevant to the thread offline. This is the last warning to all involved. Posts after this will be summarily deleted.

Last edited by noopster : 28th June 2014 at 13:00. Reason: Please stay on-topic!
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Old 28th June 2014, 15:47   #54
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Default Re: Reality check for VW: Lowers marketshare target for India

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Originally Posted by blacksport View Post
Mod Note: Please take the discussion on probability and other things irrelevant to the thread offline. This is the last warning to all involved. Posts after this will be summarily deleted.[/b]
MOD's
I assume as this part of the original thread has now been moved we can "safely" continue her??

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Originally Posted by blacksport View Post
The way I look at is, based on the above assumptions, for every NA engine that fails there would be two turbo engines that would be failing. And that tells something, doesn't it?
What it means: Out of batch of 10.000 NA engines, one will fail. Out of batch of 10.000 TC engines, two will fail. I call that a marginal difference.

You draw the wrong conclusion and the example is completely detached from reality as well.

Lets first look at the numbers and how they can be interpreted in a meaningful way:

Lets try a slightly different example to see if we explain how this works:

Say you buy a ticket in a lottery. With that one ticket you have say a change of winning of 1 in 10 million. Which, is less then remote at best. When you buy a second ticket you can proudly announce that you have doubled your change on winning!! But effectively your change statistically is now 1 in 5 million, which is still less then remote at best. So, in practice the outcome is virtually unchanged. But you can still claim you have doubled your change of winning, or you could claim you have improved your change of winning by 100%.

It is exactly the same when you are building a very reliable system from very reliable components. Yes, the total is less reliable, but only a fraction. Now how, you want to express/measure that fraction is up to you. But it doesn't change the result that the reliability is only affected less then marginally.

Secondly and more importantly is how it works in the real world. Car manufactures design and build a car (and engine) to meet a long range of different parameters, including reliability. Say they want to have an engine with a reliability of x. Whether that is a NA or TC, it gets designed to spec, including reliability. By carefully designing the individual components in such a way that the total reliability meets the requirement. As I stated earlier, you don't just bolt on a Turbo Charger to a NA engine. You do a complete redesign. And unless you change your requirements on reliability, the TC engine will come out, on paper at least, with the exact same reliability.

On the formulas, you can google for instance "how to calculate reliability" and you will find a bewildering number of formulas, white papers and what have you.

I never claimed to be an expert, all I have some first hand experience in this field during my early career in Industrial Control Systems. That meant mainly control loop response times and system accuracy predications and modeling. The days of very early electronic pocket calculators and slide rules. Yes I am that old!

Here's an article in which you can see some practical applications of how reliability calculations and modeling is done for plants. Plenty of formulae and graphs! Knock yourself out.

http://www.reliableplant.com/Read/18...ineering-plant

Jeroen
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Old 28th June 2014, 21:42   #55
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Default Re: Factors Affecting Reliability

OT OT OT.
Could someone rank in order of 'reliability' (and explain why!): Single engined, twin engined, and four engined planes.

Regards
Sutripta
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Old 28th June 2014, 22:10   #56
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Originally Posted by Sutripta View Post
OT OT OT.
Could someone rank in order of 'reliability' (and explain why!): Single engined, twin engined, and four engined planes.

Regards
Sutripta

Of course, but lets see if there are others that would like to take a stab at it first. Here's a clue; check the link I provided earlier on calculating reliability in systems.
Good luck,
Jeroen
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Old 28th June 2014, 22:38   #57
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Default Re: Factors Affecting Reliability

Leaving aside the A380, which was the last new commercial 4 engined design? The A340? (Shared with the A330, but still new).

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Sutripta
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Old 28th June 2014, 23:05   #58
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Originally Posted by Sutripta View Post
Leaving aside the A380, which was the last new commercial 4 engined design? The A340? (Shared with the A330, but still new).

Regards
Sutripta

How about, when it comes to planes, there are other factors to be considered how many engines you need then just reliability?
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Old 28th June 2014, 23:12   #59
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Default Re: Factors Affecting Reliability

ETOPS?!
Noise (BAE 146)?
Operating Cost?

Thread is on reliability.

Regards
Sutripta
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Old 29th June 2014, 05:54   #60
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Originally Posted by Sutripta View Post
ETOPS?!
Noise (BAE 146)?
Operating Cost?

Thread is on reliability.

Regards
Sutripta

ETOPS plays a big role and is ultimately all about reliability. Plain all weight is a factor too. You need a certain amount of thrust to get a 747 into the air. More engines, more thrust.
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