Kind of a crazy day at the Saturday club race for the Memphis TCS. I got there pretty early in the morning, and ran a bit on the track, which had not really been prepared too much. After about 2 packs, they wound up spraying the track with VHT cut with methanol. Instantly, we had very high traction.
Immediately, the order of the day changed from finding stability to getting the car steering. I wound up doing some things I would not have predicted. I kept the 3.5mm offset steering blocks. I tried the stock block, but it didn't seem to help much on the tight parts of the track, which were many, and almost had less steering in other parts. This is very different from carpet, but perhaps it's a function of the rubber tires. I feel like the the steering block is a big adjustment, where you work other things around that decision. So I started to raise the upper arms at the steering knuckle. The car was very stuck so this actually was not as bad as I thought it might be.
I did also try more static camber, but it almost seemed to be riding on the edge of the tire. I don't know if that was more a function of the tire setup, but it was not turning in the way I wanted. Going back to 1.0 camber, the car turned in better. Angling the upper arm as I did got enough camber into the front end in roll, so keeping more tire on the ground was fine.
One more note on the front end, I did not have any grease on the kingpin to start the day, and one set of tires wound up really making the car hop. So I went right to 120K diff oil. Somehow, I didn't think it would make a huge difference, but in reality not only did it make a huge difference in the hopping, the car was MUCH more responsive. Sometimes, on carpet, I thought some over responsiveness was coming from the damper plate, but I now think that over dampening the kingpins is a lot of the reason for the twitchiness.
The upper deck was also part of the fun. I wasn't sure if the added traction of the VHT would make a big difference in what I needed to do as far as stiffening the chassis. Starting with only the pivot post connecting the upper deck, I made some changes, but that is where I ended. I tried 2 posts in both the forward and middle positions. Both provided a more locked in feeling, but they took away some steering, especially on turn in. The other part is that the more flexible chassis hooks the car up in general, especially in rear traction. As the day went on, traction seemed to fade a bit, so the most flexible option was still the best.
The rear shock height was also way more sensitive than I expected. For much of the day, I wasn't quite sure what to do to get the car to keep turning off the corner. I tried a stiffer spring, which was ok, but not quite what I was looking for. I took only 1mm off of the rear ballstud for the shock, leveling it a bit. This made the car very responsive, and almost loose! The next run I added the spacer back, along with an additional 0.5mm and this went right back toward a push on power. This actually made it possible to use different sets of tires based on how much rear bite the car had on power. I did not change the front ballstud at all, and I am curious if it is as sensitive as the rear ball stud is.
The little 1800 pack also came out for this race, with as much traction as there was. I ran it until about mid afternoon, when traction seemed to fade a bit. The 1800 is perfect when traction is high, since it is obviously faster even to the naked eye. I had a guy ask me if I had a brushless motor in the car, lol. However, as the day wore on, I went to an Orion 3200 to provide some more mass, and that turned out to be the best choice in the later afternoon. The track had quite a few 180s and slow sections, so the stability and forward traction were much more valuable than overall speed.
For tires, I started with a set of Option soft rears and kit fronts, with stock inserts. The tires actually were great. Later I tried the same type of tires with a 26mm sedan insert, and the car actually locked down quite a bit, and started to push. I was surprised, but even with the high air temps (99* F) softer inserts were better. Later, on advisement from my buddy Jay, I tried a set of tire with no insert at all. This can actually be a good option when the temperature is high since the tire cools better. I did notice that I ran better in the last half of the race. At the same time, as the day wore on and traction faded a bit, these tires pushed just a bit. The stock inserts were just a bit better, especially on steering. The thing you had to be careful of with the stock insert was roasting the tires at the end of the race.
The car was definitely really good, so tomorrow should be very exciting...........