.....Static, if you added 7000 lbs to the rear end so it is 8050 lbs and 150 lbs on the front, the center of gravity (balance point) would not be the same place as before the weight was added therefor the center of gravity moved. Ron
Ron this comes back to the same thing that we have been talking about. The term center of gravity only applies to the effects "gravity" has on the car. It's weight is determined by gravity not any other forces. Sure these other forces can be used to help make the car more stable, have more traction, etc.. We are not denying that what we are saying is that those are forces and they don't effect the cars center of gravity. They might effect how the car behaves while the forces are in effect but what if they are no longer in effect.
If those forces go away what you are now relying on to keep the car going down the course in a more or less nose in front of tail position is the relationship of center of gravity (CG) to center of pressure (CP). This is the point that George P. was trying to make in BRN and Tom Burkland made in a different issue and they and others on here and other places have made in the past. These are people who have been there and done that for years and years. They know what it takes to run well over 400 mph. We can appreciate their advice and use it or not. Personally I'm trying to use it.
Most people are envisioning a wing or spoiler taking care of improper use of what we have learned about where CG should be in relationship to CP. There are a lot of things that can put the car in the position where you would of wished you had taken advantage of keeping the CG ahead of the CP. I'll name a few that could take the downforce the wing is giving out of the equation pretty quick.
1. You run over something or for no apparent reason a tire blows.
2. You blow an engine and the drivetrain locks up the rear end.
3. You encounter a freak crosswind.
4. You hit a slick spot in the course (Speed Demon).
5. You have more HP than in the past and misjudge it (Speed Demon again combined with the slick part of the course).
6. Your transmission or rearend locks up again locking up the rear tires.
7. You might loose a body panel.
8. You might not have the wing or spoiler set to the correct angle needed to insure you aren't going to spin those tire. (this brings up the point we are struggling with. What is the angle that will give us the downforce we need on the Stude. About the only way we are going to know is trial and error and some of the error might involved tire spin and we don't want the car spinning so will keep the CG ahead of the CP. I doubt very few people that are using their spoiler or a wing for downforce know what that down force actually is at different speeds. Anyone actually know that?)
There are probably a number more. The point is we have been given good info from good well respected sources. It is now up to us if we use it or not?
Sumner