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      10-26-2007, 10:52 AM   #82
gbb357
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Drives: IS300
Join Date: Oct 2007
Location: New York


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Quote:
Originally Posted by lucid View Post
Guys, I have lost track of the real difference of opinion in this debate. Swamp has done some detailed modeling of the 0-60 scenario with CarTest, which does seem like a fairly comprehensive and reliable simulation environment when it comes to that sort of thing. I believe he has validated the accuracy of the environment for several cars by using manufacturers' specs as parameters for the simulation and comparing the outcomes to the performance figures reported by magazines. That said, it is valid to question a simulation outcome--regardless of the comprehensiveness of the model being used--which I guess is what gbb357 is doing. For instance, my understanding is that C&D is using rolling starts in the 0-60 test. Does CarTest model that? Where does CarTest get the necessary data for modeling transmission losses, and how accurate are that data (I am not talking about the conceptual physics model that is being used to simulate the losses; I am referring to the actual parameters). Regardless, I think it is possible to say that, with some degree of confidence, an engine might be underrated if things simply do not add up in the end. Maybe the issue here is what level of confidence one can make such a statement given there might be uncertainties in the simulation model. Is that the basis of this debate? If it is, then I don't see how one can come up with a definitive answer in the absence of a larger statistical database which shows how CarTest simulation outcomes compare to reported real-world performance figures from multiple sources. Maybe the authors of CarTest have published that type of information?
I never doubted Swamp2's data or calculations. As a matter of fact i think it is quite valid and accurate if you look at it scientificly. The point that i'm trying to make is that you can have all the simulations, calculations and what not, it's not going to be as accurate as the real world testing. That is the final conclusion of all. Of course you're going to have mistakes, wheter it'll be instrumentation or human error. Can it be skewed or manipulated, of course it can. But these magazines don't really have any reason to do that especially if their reputation is on the line. As a matter of fact, i think it might be an incentive for them to get the best performance out of each cars they test. It's bragging rights. BTW, C&D's rolling start acceleration test is a seperate test. That simulates real world driving for you and me. That's why it is usually a lot slower compare to their regular test. And furthermore, the times that the IS-F got from C&D is not that far off from the M3's and RS4's results. And their specs are very close also, so i don't see this being controversial at all.