So after several races with the aluminum chassis on the new black CRC carpet, it's time for some thoughts...
Oddly enough, I sort of felt better about how the car set up with this chassis on the older gray CRC carpet. The first time it put it down, it was awesome. On the black carpet, it was a bit harder to nail the setup. However, this could also be partly due to the high bite at both the races I attended, especially the ROAR nationals in St. Louis.
Part of the problem at the ROAR race was a lack of mid corner steering. Going too aggressive with the front end would only result in a traction roll anyway, so my mistake may have been going with the least flexible front end parts on the aluminum chassis. I used the cross brace for the lower arms, and a pair of Xtreme racing lower arms which have extra bracing. I feel like that may have been what was limiting the car in the middle of the corner. Upon returning to my home track, which has the gray carpet, I went back to the standard lower arms and removed the brace. I felt like the car was a little more forgiving to get around the track. It was hard to tell how much this affected the mid corner steering, since the grip level was different, but at my track mid corner was good. I will return to the Ft. Wayne track in the next few weeks, so it will give a chance for me to revisit that issue.
I would like to point out that the eventual champion at the ROAR race and the rest of the local racers ran the graphite chassis on the car, and did not seem to have a big problem with traction roll. Sometimes the cars looked edgy at the start but they were able to manage that for the most part. Part of this may also have been the tire dope strategy. I noticed some guys doping their tires 15-20 minutes early, so that the compound would dry on the tires. I tried this as well and the car finished the race better. It also didn't seem to make the car any harder to drive. Letting the compound dry might have helped alleviate some of the initial oversteer/tire lifting that occurs when the tires are wiped just before the race.
In general, I think that the aluminum chassis makes the car very consistent, and reduces a lot of the tendency to traction roll. I probably went a little overboard on the stiffer components for the front end. I would imagine that the cross brace for the front end is not necessary in most cases with the aluminum chassis. The stiffer lower arms might be helpful depending on the level of traction. Being aware of how these parts affect the car, I'd like to test again on the black carpet. I should have a little more knowledge in a few weeks.