Originally Posted by
DavidNERODease
If the CG of the battery pack is lower than total CG of the car then it lowers the overall CG if the battery increases in weight and it's CG still remains lower than the overall CG. A lot of people underestimate the effect of the body on the overall CG and therefore it's higher than many racers think. It's particularly bad on VTA and USGT cars where the finished bodies are well over 100g and the CG of the body is way above the overall CG. It's such a drastic effect that even the paint and stickers affect it. I have actually done the CG calculations on WGT chassis several years ago when I had traction rolling issues. To define measurable - I was able to the lower the overall CG by 4.13mm (height from grade went from 29.77mm to 25.64mm) mostly by changing the body/paint/stickers/body trimming. Plus a little with added weight (7g of lead on the chassis lowered the overall CG of the WGT car by 0.26mm). Of course the effect of the body is less in TC especially if you are using a lightweight shell. Back to the heavier battery pack in a TC - I'm fairly confident that CG of the battery pack is quite a bit lower the overall CG of the whole car - mostly due to the effect of the body, but also the motor CG which is much higher. And there is still a lot parts with CG's above the CG of the battery: the body posts, shocks, shock towers, diffs, wheel/rims, axles etc. It's very deceptive to look at until you really look at.
Interested in your numbers and how you calculated them. I did calculate my car's CG and to have a 4.13mm lower CG I would have to make very big changes.
Originally Posted by
thisguy2849
Mike Gee who won 17.5 at st Louis ran a car with a pcr 8200mah pack that put his car at 1410 instead of the 6200mah pack that made his car 1380 because the longer voltage peak was more advantageous than the light weight and balanced
Incredible. Is it standard procedure now, meaning it proved itself on track as faster than lightweight cars?