Oh, I KNOW how concrete the process isn't. I've been pretty intimately involved in the whole "formula" movement, going back 7-8 years now and have kept close track of how we got where we are.
That's why I worry so much.
I'm going to sound like I'm arguing two sides here but the primary issue to my mind is repeatability - an aspect of how reliable the system is. Whether it is RIGHT is a separate issue and frankly, I think that's less important, but multiple people on the ITAC running the car through the same process should get the "same" result.
The question then becomes what does "same" mean. That's where acceptable error comes into the equation and frankly, there's no way that we can expect closer than +/- 75#. So the difference between Darin's 2675 and someone else's 2600 is essentially no difference.
You've got no standing in the rules or processes in use to request a move to ITB at the same weight. The system just doesn't accommodate that. Or you CAN ask but the response is guaranteed.
Part of the reason I wrestle with the validity of using "known gains" is that we pretty much never know what we know. When you say, "...compaired to a car like the Z3 where we see 3/4 of the predicted hp gain and 3ft/lbs of torque, that's like less than a 2.5% increase" that carries exactly no weight to others, regardless of how confident YOU are in the figures. We chuck around percentages, Dynojets, other stuff - lap times - but unless someone can demonstrate their methodology, it's noise.' Andy says he got 108 whp with his SM. He might have all the confidence in the world about what that means but it doesn't mean diddly if we think critically about it.
Regardless, power is an OUTCOME or OUTPUT VARIABLE - a result of what we do, rather than something we control directly. You can't just "make horsepower:" if you figured out a way to do that, you'd be a rich man.
We change things and expect power as an outcome. It's a first assumption of the IT ruleset that we try to control INPUTS - limiting what we are and are not allowed to do to the car - and that competitiveness and racing happen out of those affordances and constraints.
If we want to start down the path of making classing decisions based on outputs, the logical extreme is to skip straight to a bracket racing model, where we enter a laptime class and if you exceed your index, you break out.
K
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I could care less what James Clay at Bimmerworld says, he's NEVER built an ITA legal Z3. Besides there are much more knowledgeable shops out there. (sorry Mr Clay, but its truth)
because the process doesn't take into account the fact that different factories prepare their motors to different levels. As Rob and I have accerted from the very beginning, when BMW built the M-44 they didn't leave many stones unturned, so that building a race motor to IT spec just doesn't result in the same potential as the "formula" predicts, it's just not there! I'm not talking about just 50-75lbs, the Z3 should probably drop 150lbs to be on par with the rest of the field. In addition, the Miata being classed at the earlier cars 128hp neglected the fact that there's a lot more to be had out of it, so much more that just a year and a half latter they could up the hp by 5 easily. This coincides with SM having a weight preassigned to it that gets carried over to ITA. In this way the Miata actually by-passed the process and was classed at it weight way light and probably needs to add 150lbs. So in effect this is what should probably happen:
