Your approach has raised a lot of question in my mind, I'm going to start with a few around the suspension side of things. I'm not going for everything I could query (not even close) as I don't want to make this a mess.
However:
With a Center of Mass measurement and tire G-force, it gives me the load transfer under ideal cornering.
How do you obtain the CoG for the stock car and then recalculate it for a modified car (particularly one that has had any form of weight reduction and/or stiffness mods added.
GT5 doesn't give you close to enough information to calculate this.
CoG and tyre lateral and longitudinal forces are not enough to calculate load transfer at all, and its unclear what you would consider 'ideal' cornering, nor have you defined what type of corner and the stage of the corner itself.
Once again I don't see how you are going to obtain the information to be able to calaculate it.
Please don't worry about the calculations involved in vehicle dynamics, I understand they more than well enough. I am however interested in exactly what values you are using and how you are using them, as you don't have close to enough information detailed about to calculate what you claim, nor am I convinced you could even obtain accurate values for some of them.
This tells me the "weight" over each wheel during cornering, including whether or not I have lifting forces on a particular wheel.
Not with the information you have outlined above it doesn't.
It gives me the roll angle of the body during ideal cornering. Then, it takes into account acceleration and braking, and tells me all of that data again except this time it assumes first that I am turning while accelerating, and then turning while braking.
Once again you are missing a significant amount of information to be able to calculate this.
The sheet tells me if the front end rolls before the rear end does, and what the degree of angle is rolls is. It tells me the visual change in suspension drop on the outside of the car under cornering roll, at each wheel. It tells me the ratio of weight on the inside to the outside of the car under cornering, which I want to maximize to 1 to get the greatest cornering grip.
Not without knowing the suspension type used on the car (and once you fit any form of PD modified suspension we have no way of knowing what that is), which would be required to calculate the roll centers and suspension travel arcs for each wheel. Oh and all the info your missing from above as well.
Of course, no car has a 1:1 ratio, but the higher the number the better. It tells me how far the nose dips when I brake. All of these length of suspension travel measurements are important, because they tell me for a given spring rate set whether or not I am going to bottom out the car under normal cornering. All of these are kept in ratios similar to a car I am already capable with, and can be intensified if I want to speed the car up.
How do you know the length of suspension travel?
GT5 is not going to give it to you, nor without knowing the exact type of suspension the car is fitted with are you going to be able to calculate it. You are also working on the assumption that spring rates are the only factor involved in this, which would not be true. Damper values, which affect the speed of load transfer (but not the amount) will also play a secondary role in this, yet you have not mentioned them at all.
While I certainly admire your zeal to get a process that works for yourself I can escape the fact that you are either missing so much information that is required or having to guess at the values that it would make the calculation of these values almost redundant.
One reason why it may 'feel' as if its working for you (aside from the placebo affect) is that GT5 tuning actually doesn't change the fundamental balance of the car by anything close to the degree it should, nor do certain suspension changes act as they should in the real world.
One good example of this would be a car with spring rates and damper set as low as they could go, as load is initially paced upon it the dampers are going to react quickly and allow that load to compress the spring with minimal resistance. At first this corner of the car is going to act as a soft sprung corner should, however its also very quickly going to reach the limit of its suspension travel and hit the bump stop. The second that occurs you now have a spring rate that has just shot through the roof, as its effectively being 'sprung' by the bump stop and physical suspension components, with the corner of the car now having all the characteristics of a spring with rates far higher than just about any commercially available car spring (and significantly higher than anything GT5 has available). Given this limitation (and others of course exist) suspension tuning within GT5 is always going to be within a quite narrow range of parameters, with far less extremes than the real world sees.
While the Fairlady Z has nearly 280 ft/lbs at the rear wheels
No it doesn't.
I can tell you right now that if your using that assumption in your calculations then you are quite wrong, I would however be interested to know exactly how you came to the conclusion that it has "nearly 280 ft/lbs at the rear wheels"?
