So Sunday I was trying to get some last minute testing in at the local track before setting out for California and the Tamiya Nationals. There was a bit of rain during the day, and I had a lot to try out, so I was scrambling a bit. Not to mention, there wasn't an F1 turnout, so I was trying the car between rounds once practice ended.
A couple quick things that stood out to me:
One thing that I had used in the past on the F103 was the shorter kingpin setup that traps the spring between the top of the steering knuckle and the upper arm on the standard front end. Usually, the spring rides under the lower arm. I can't remember the Tamiya part # or the name, but it's very close to how an Associated "old school" front end is set up. The main point is, it seemed to produce a bit of preload on the spring, and I even added shims at times to increase the preload. The car has a more stable feel, especially entering the corner. This was helpful with the 103 on foams.
I was trying some "sag" or droop on the front end of the 104 by removing a .5mm spacer. That did add some on power steering, but it came with a less than predictable steering feel. Going to a extra .5mm spacer over standard (.5mm preload) gave a very confident steering feel. The relationship of the steering wheel to how the car turned was very proportional, very linear.
I also changed the steering links to the forward hole in the steering arm. This does two things, changes the ackerman relationship, and also speeds up the steering. Mostly I wanted to change ackerman, but I didn't want to move the servo. It was easier to have an extra set of links. I think that it helped the car get through the turn a little better because of less wheel scrub. Now, what I'd really like to do is set the servo to have straighter steering links (mine are currently very angled) and also go back to the rear holes in the steering arm.
Another positive result was adding chassis posts in the forward most holes. My car had a bit of a loose out of the corner/under power condition. I remember I had tried the posts before at the Memphis race, and it tightened the car up a little after turn in. So I added the posts, hoping it would help. They actually did tighten the car up a bit where I needed it, coming off the corner. Memphis was pretty high bite, so the posts were not needed there, but the local track facility's beautiful euro style road course is literally 20 feet from their off road track. This does tend to throw some dust on the road course unless there is a ton of cars on the track and a lot of sugar water.
Overall, progress was good. I would have also liked to have tried increasing the center shocks angle, as it usually stabilizes the car, but it wasn't super important since I have tried that adjustment several times before.
Side damper oil was also increased to 10000 wt diff oil to aid in stability as well, but that is a pretty well sorted adjustment.
One other thing was that straight Simple Green to clean the tires seemed to have the longest "run" on the track before the tires got dirtied.