Quote:
Originally Posted by thom4782
because statistics show that the uncertainties between Porsche reported failure rates and actual ones are likely very small to make meaningful differences.
|
This would be true if the cars lived in a vacuum post-warranty. But they are all subjected to very different types of driving and engine care which can drastically affect the number of failures. The more mileage goes on the engine, the more those variables can sway the numbers. Hence, within the specific set of numbers you are using, (and I'm not sure which statistics you are comparing those to) you could be correct but the problem is that you are using Porsche's numbers which were not vetted or subject to review by an independent third party and certainly not held to a standard that could pass any sort of regulatory muster. The fact that Porsche can't even tell you which cars had dual row bearings leaves me with serious doubts about the accurracy and thoroughness of their reporting as a base line.
To me the main proble with analyzing these stats for 'beyond general' analysis is that this is a dynamic failure, it's not like a product testing for light bulb where an item is subjected to the exact same rigors accross each test sample. Every test of the IMS bearing (driver habits) is different to the next test with no way of measuring that variance.