How old are you and am I too young to drive G29?
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Scottish Borders
sars said:Chris_D said:
I don’t know where to start, you talk about basic engineering and then send a link concerning fibre reinforced plastic
Two relevant topics that you should look up, FMEA’s and for safety engineering, SILs, stating that the more sophisticated or complex a system is increases the probability of failure is just wrong and naive. There’s this thing, oh been out for years, mean time between failures, any company that mass produces any engineered product will statistically know a, how it will fail and b, when it will fail, therefore the automobile industries push to create reliability from the outset. Vehicles now are far more reliable than they were twenty years ago, even with more technology, all of which is well proven.
+1
The complexity vs failure law doesn't hold up if the designers and more importantly the bean counters allow proper development and appropriately spec'd parts.
When you look at how many bits say an E89 has, if FIAT had built it, back in '78 then it would never go for more than a day without some electrical failure. Most E89s just rumble on.
pvr said:
IMHO its an unfair comparison.
Price of spares is driven primarily by market forces and the ability of the manufacturer to control that market.
Common parts for common cars are cheap because the manufacturer can't mark them up agressively due to mass competition.
Unusal /slow moving parts are marked up severely because they can and to reflect slow moving stock and associated costs.
Cost of manufacture is only a small part of the equation. Porsche may charge 30 times more, but I can assure you that there isn't 30 times more physical or intellectual content!
There is a buoyant market in re-furbishment which is offering cost effective solutions to many expensively priced parts.
So on topic, of course you’re not too young! You might be younger than the average g29 owner, but as said already; it’s the later generations who usually have more disposable income, time, and less requirement for a family bus.
I got my first z4 e85 9 years ago, Z4 MC when I was 26/27.
Also breaking down a midlife crisis … it’s having a panic and doing things before you think it’s too late. Lucky you if you don’t have to wait until it’s too late
I got my first z4 e85 9 years ago, Z4 MC when I was 26/27.
Also breaking down a midlife crisis … it’s having a panic and doing things before you think it’s too late. Lucky you if you don’t have to wait until it’s too late
B21 said:sars said:Chris_D said:
I don’t know where to start, you talk about basic engineering and then send a link concerning fibre reinforced plastic
Two relevant topics that you should look up, FMEA’s and for safety engineering, SILs, stating that the more sophisticated or complex a system is increases the probability of failure is just wrong and naive. There’s this thing, oh been out for years, mean time between failures, any company that mass produces any engineered product will statistically know a, how it will fail and b, when it will fail, therefore the automobile industries push to create reliability from the outset. Vehicles now are far more reliable than they were twenty years ago, even with more technology, all of which is well proven.
+1
The complexity vs failure law doesn't hold up if the designers and more importantly the bean counters allow proper development and appropriately spec'd parts.
When you look at how many bits say an E89 has, if FIAT had built it, back in '78 then it would never go for more than a day without some electrical failure. Most E89s just rumble on.
I think one is confusing engineering with chaos theory where everything that can go wrong will go wrong. Hence engineers work on as many scenarios as possible to avoid the unknown failures. Obviously real world nicks in and you get failures that aren’t expected and premature failures.
However, modern cars are far more reliable than cars 30 years ago. The morning starter motor whine from every neighbour in the winter as their cars wouldn’t start was a a regular sound! Never happens now.
Engines had to be rebuilt regularly with head gasket failures.
Oh and drum brakes? Arghhh.
I also find it funny that e85 are considered basic today as at the time it was state of the art and I’m sure people probably complained about it being too much by “purists”.
Hmm, people starts referencing papers, nice. Seems my three years of PhD research into dependability of computer system and four years of daily work on functional safety may have given me a little bit more materials to type.
Anyway, before I go into other materials, let's discuss the paper you referenced. In any of the system failure probability modeling methods as discussed in the paper or referenced by the paper, have you seen that the time (T) is always an important factor in the modeling? More specifically, the time here is referring to the duration since a system was initially built till the point when the probability is observed. In Layman's terms, the time (T) is usually known as the age of a system.
Now, with above concept cleared, based on my understanding of this material and many other referenced works, what can be summarised in general is that the probability of system failure is positively correlated to the age of the system, or known as time (T). With this in mind, then let's look at the age of E85 and G29. Based on the very unscientific source of material (Wikipedia), the E85/E86 generation was produced from 2002 to 2008, and G29 generation is being produced since 2018. If compared the oldest G29 and newest E85/E86, we can see that there is an age difference of 10 years. If the age is then taken into any of the system failure probability models, what is likely to be observed is that the probability of system failure on E85/E86 is significantly higher than the probability of system failure on G29. Then, if data observation by human eye is not convincing enough, what can then be done is do a simple statistical test (here, based on the type of data we want to test against, the result from t-test will be widely acceptable. Hence, let's use the t-test), and the p value will be significantly smaller than 0.05, which indicats the observation is statistically significant.
Now, one may also argue that a car should not be considered as one system. Instead, each individual function/feature should be considered as a system. In this case, the G29 has significantly more number of systems than the E85/E89 has; and while the probability of system failure of each individual system on G29 might be much lower compared to E85/E86, the combined probability of system failure will be increased exponentially due to the more number of systems. Well, you are right to this. However, the systems onboard can generally be categorised into two groups: safety critical system and non-safety critical system. Here, I give the drivetrain systems as the example of safety critical system and the idrive system as non-safety critical system. For the safety critical systems, with any failure occured, the systems are then considered as compromised and have to be rectified before the vehicle can be considered as a roadworthy vehicle. On the other hand, upon the failure occured on non-safety critical system, the vehicle is still functional as a roadworthy vehicle.
Based on this concept, let's look at a very simple component, which definitely appeared in engine control unit (ECU) as well as in idrive system, analogue-to-digital converter (ADC). The youngest ADC in E85/E86 is already 10 years old and as an electronic analogue component, it may have already drifted outside the design tolerence whereas the oldest ADC in G29 is only 3 years old and the likelihood of its value drifting outside the tolerence is significantly lower. In this case, yes, G29 has idrive so there is at least one more ADC that can go wrong compred to E85/E86. However, does that really matter compared to an ADC in the ECU? I guess the answer is no. Then, when the G29 reaching 10-15 years old and the reading from ADC in ECU starts drifting away and we must repair it, the E85/E86 will then be like 25-30 years old and I guess it will be much harder to even find the part to do the repair. Furthermore, all above example is based on the software technology is the same between G29 and E85/E86. In reality, software technology has also advanced a lot since 2002, which has the capability of fault detection, fault tolerence, as well as fault rectification.
You are right, they are all basic engineering. However, there is science behine the engineering.
Anyway, before I go into other materials, let's discuss the paper you referenced. In any of the system failure probability modeling methods as discussed in the paper or referenced by the paper, have you seen that the time (T) is always an important factor in the modeling? More specifically, the time here is referring to the duration since a system was initially built till the point when the probability is observed. In Layman's terms, the time (T) is usually known as the age of a system.
Now, with above concept cleared, based on my understanding of this material and many other referenced works, what can be summarised in general is that the probability of system failure is positively correlated to the age of the system, or known as time (T). With this in mind, then let's look at the age of E85 and G29. Based on the very unscientific source of material (Wikipedia), the E85/E86 generation was produced from 2002 to 2008, and G29 generation is being produced since 2018. If compared the oldest G29 and newest E85/E86, we can see that there is an age difference of 10 years. If the age is then taken into any of the system failure probability models, what is likely to be observed is that the probability of system failure on E85/E86 is significantly higher than the probability of system failure on G29. Then, if data observation by human eye is not convincing enough, what can then be done is do a simple statistical test (here, based on the type of data we want to test against, the result from t-test will be widely acceptable. Hence, let's use the t-test), and the p value will be significantly smaller than 0.05, which indicats the observation is statistically significant.
Now, one may also argue that a car should not be considered as one system. Instead, each individual function/feature should be considered as a system. In this case, the G29 has significantly more number of systems than the E85/E89 has; and while the probability of system failure of each individual system on G29 might be much lower compared to E85/E86, the combined probability of system failure will be increased exponentially due to the more number of systems. Well, you are right to this. However, the systems onboard can generally be categorised into two groups: safety critical system and non-safety critical system. Here, I give the drivetrain systems as the example of safety critical system and the idrive system as non-safety critical system. For the safety critical systems, with any failure occured, the systems are then considered as compromised and have to be rectified before the vehicle can be considered as a roadworthy vehicle. On the other hand, upon the failure occured on non-safety critical system, the vehicle is still functional as a roadworthy vehicle.
Based on this concept, let's look at a very simple component, which definitely appeared in engine control unit (ECU) as well as in idrive system, analogue-to-digital converter (ADC). The youngest ADC in E85/E86 is already 10 years old and as an electronic analogue component, it may have already drifted outside the design tolerence whereas the oldest ADC in G29 is only 3 years old and the likelihood of its value drifting outside the tolerence is significantly lower. In this case, yes, G29 has idrive so there is at least one more ADC that can go wrong compred to E85/E86. However, does that really matter compared to an ADC in the ECU? I guess the answer is no. Then, when the G29 reaching 10-15 years old and the reading from ADC in ECU starts drifting away and we must repair it, the E85/E86 will then be like 25-30 years old and I guess it will be much harder to even find the part to do the repair. Furthermore, all above example is based on the software technology is the same between G29 and E85/E86. In reality, software technology has also advanced a lot since 2002, which has the capability of fault detection, fault tolerence, as well as fault rectification.
You are right, they are all basic engineering. However, there is science behine the engineering.
-Tom- said:So on topic, of course you’re not too young! You might be younger than the average g29 owner, but as said already; it’s the later generations who usually have more disposable income, time, and less requirement for a family bus.
I got my first z4 e85 9 years ago, Z4 MC when I was 26/27.
Also breaking down a midlife crisis … it’s having a panic and doing things before you think it’s too late. Lucky you if you don’t have to wait until it’s too late
Thanks mate.
sars said:
This bit is actually acceptable. The material he attached talked about modeling the probability of system failure. fibre reinforced plastic can be considered as one specific area of application of the model. The main thing is that regardless of which way to model the probability of system failure, age is and will always be one of the must have variable in the model. Ironically, he doesn't know this. Neither does he know that the youngest E85/86 is already 13 years old whereas the oldest G29 is only 3 years old.
I don’t know where to start, you talk about basic engineering and then send a link concerning fibre reinforced plastic
Two relevant topics that you should look up, FMEA’s and for safety engineering, SILs, stating that the more sophisticated or complex a system is increases the probability of failure is just wrong and naive. There’s this thing, oh been out for years, mean time between failures, any company that mass produces any engineered product will statistically know a, how it will fail and b, when it will fail, therefore the automobile industries push to create reliability from the outset. Vehicles now are far more reliable than they were twenty years ago, even with more technology, all of which is well proven.
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Damn you turn me on kitten...... :wub:
But you really don't need much power to enjoy a car that weighs, lets say a ton. Leave out most of the unnecessary creature comforts and such a weight is easy to safely achieve, with modern engineering methods. The only real problem is the marketing men, who do a very fine job of convicting the vast majority of people that they want things they don't need. I admire the AM DB9 as a thing of beauty, that I have aspired to for years. But as a Sports car it's a waste of space. Too heavy, too complex, so I have put it off until the day I don't want a sports car any more. I think what I am saying here, is that at 60 I feel I am too young for a G29, in terms of something I want to drive for fun.sars said:buzyg said:Colin Chapman had it nailed as far as weight goes.
This is often misunderstood, Colin Chapman did not invent low weight cars, he invented the monocoque chassis which meant a much stiffer and stronger chassis with less weight. Weight is important when you are power limited, our cars are not power limited and unfortunately you can’t change the laws of physics, more power means, more cooling, bigger breaks, wider wheels and more rigidity and ultimately for a relatively low cost car this equals more weight.
[ref]buzyg[/ref], I don’t disagree with the points you’ve made, but comparing the difference between a e85 and g29 when there’s less than 10% weight difference is not like comparing a Z4M with a Caterham 7 but you wouldn’t want the latter as your daily drive.
Ultimately the best drivers car is not necessarily the lightest or the most powerful as the 911 GT3 keeps proving year on year
Ultimately the best drivers car is not necessarily the lightest or the most powerful as the 911 GT3 keeps proving year on year
Scubaregs said:
What were you doing in Campbeltown?
ori said:
That’s certainly true. When Chris Harris reviewed the GT3, he specifically said that the GT3 chassis setup is brilliant on track but is a bit too busy if driven daily.
I think when we said G29 is a good handling car or a fun car, we are all from a daily drive perspective. To be honest, I personally will not consider Z as the track weapon. Also, I think life is full of compromise.