Nats day two: Practice

Today I managed to get though my to-d0 list.

  • I replaced my shock oil with 400 wt (from 600wt). For the job I borrowed a vacuum chamber (like this). It was awesome… I have to get one. The car was much more drivable with the softer oil. In particular, there were some bumps coming onto the front straight which always made me lofty, but now the car just dipped through them smoothly.
  • I fitted a longer piece of antenna tube, and bent it down so it still fits under my shell. I hoped this would solve my radio glitch i had seen yesterday. Unfortunately the problem wasn’t solved, and happened a few times right in front of me in the pits. I noticed the ESC lights changed when I had this problem… so it does seem like a radio thing. Perhaps my ESC -> radio connector is suspect.
  • I went down 2 (!) teeth in pinion from a 24 to a 22 (with S=80 and IR=2.0). My motor temps went down from 80 C to 63 C. This allowed me to crank my DRRS rate to level 9. I felt more punchy through the in-field, and still as fast on the straight.
  • I passed all tests in scrutineering: body over 120mm (i am about 122mm) from bottom of chassis, weight over 1380g (i was 1390g with the Revtech 6900 lipo), wing below top of body (pinned it down with a 2nd pair of screws and trimmed it).
  • I discovered my two weak points on the track are at the ends of the 2 sweepers. (1) On the end of the front sweeper I tend to push wide, and I see good guys gaining a couple of meters on me there. (2) At the end of the second sweeper there is a braking zone that I cant time very well. The fast mod guys hang 2 feet from the inside rail and chuck a 90-degree left immediately after the pylon.
  • Across the day I became more and more aware that I should be consciously rolling the car though the turns (and not chucking it around).

I improved my best lap-time from a 21.7 (yesterday) to a 21.3 (today). This came in a session after baking in tyre sauce 80 C for 10 mins until almost dry. I had a really bad spot on the driver’s stand in that session and am sure I could have got more out of the car. The fastest times of the day were 20.2 and 20.3. Is it possible to find that final 1 second?


  • Build a new ESC -> radio cable so that you don’t have as much stress on it.
  • Make sure you are not pulling your antenna cable too hard.
  • Set the end points on the ESC again turn down the throttle EPA a few % when you do this, so that the radio is definitely seeing full throttle.
  • Try a stiffer sway-bar on front… or both.
  • Try a little more rear droop to help turn-in off throttle at the end of the back sweeper.
  • Give yourself a bit more drag brake and learn to use that everywhere.

Now… get some sleep coz I have to wake up in 5 hours, and then race for 14 hours.