[bruce.augenstein@comcast.]

Originally Posted by lucid

I would actually agree with this if we were talking about BMW trying to achieve an "official" time for its own car. As you are saying, BMW has put in thousands of laps with the M3, so they will know its limits and how uncontrolled variables affect lap time better than anyone else, and will optimize their run accordingly, and keep on coming back until they think any better can't be done.

Originally Posted by lucid

However, the discussion is about a car mag testing different cars at different times. I doubt that any one magazine will have the knowledge base, funds, or the motivation to keep on optimizing under several different conditions for any given car.

OOPS! I was indeed talking about the broader subject of "best" lap times, as opposed to a single magazine's times. My bad. I personally look for best times, and then look for other variables such as tires, whether the manufacturer supplied the results, etc.

Does anybody know if the magazine in question at least attempts to normalize their results?

Originally Posted by lucid

As you know, I realize different tires will make a difference. So, the point is what is "fair" and "representative". I still don't see how replacing an item that is meant to be replaced in short intervals with aftermarket alternatives within a certain range all of sudden makes the car's performance "non-representative". There is ambiguity associated with this variable however one tries to justify it. So, now CUPs are a part of some low volume package--most likely not sold in the US--and all of sudden we go, "OK"?

No, not OK, or least not in my book. If a car is available with and without such a tire (think Porsche Turbo), then in that case a second a minute is a pretty good estimation of the difference. In this case as an example, Walther Rohrl did a bunch of 7:49s until the switch, whereupon 7:40 became the new number, if memory serves.

The reason why stock tires should be the norm is that switching them makes for a hopelessly complicated comparision. As an example, my guess would be that the Z06 would benefit a good deal more from a switch to Cups than a Porsche Turbo, since the runflats on the Vette are an amazing weak spot on the car. Ever try one? They're a euphoric but scary ride.

Originally Posted by lucid

What I mean by that is that these magazine times are for us to "talk about", and do not really have the high degree of accuracy associated with them that people often read into them, and should be treated as low-resolution measurements in discussions. When BMW reports a time, I see more of a point in comparing that with official times reported by other competitors.

I would agree to the extent that those times are likely to be lower resolution than factory times, but still fairly close - assuming they kind of do it for a living, so to speak.

Originally Posted by lucid

Yep, that sums it up. I think the variation associated with the driver alone can easily be in the +-10 second range alone for a 8 minute track in a magazine test. You think differently, and that's cool.

I would actually agree, but are you saying that the magazine uses different drivers? Good grief!

Bruce

Edit: Ok, I just caught up on the string, and it seems that the magazine in question does indeed seem to be careful about their testing. In that case, I'm thinking maybe a half-second per minute as the accuracy, or a little less.