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Timothy Bennett >>
Increasing the RARB makes sense... that will loosen me up through the turn. I stiffened the rear sway bar one tick to 0.600".
By moving weight to rear, I assuming you want to heat up the rear tires. OK... so how much weight? I decided to move about 18 lb. from the front to rear.
Here's the results.
Lap Times (sec)
Best Worst Average Std Dev Variance
start (laps 1-10) 23.828 24.562 24.052 0.213 0.045
middle (laps 11-20) 23.846 24.571 24.109 0.231 0.053
end (laps 21-30) 23.872 24.265 24.057 0.128 0.016
total (laps 1-30) 24.072 0.187 0.035
1/4 Run - Braking can create a loose condition at the entrance to Turn 1. Pumping the brakes seems to help. Also, I had to be careful not to get back on the gas too soon. Definitely easy does it in the corners. We have definitely loosened the car up through the corners. Driving hard into the corners creates a potentially dangerous situation. Tire wear indicator show all four corners are still green.
1/2 Run - Really loose into Turn 1 at the beginning of this part of the run (laps 8-11). By the end of this part of the run (lap 15), the setup has stabilized somewhat, and I'm able to keep the lap times more consistent. Tire wear indicator on all four corners still showing green.
End of Run -
Tire Wear
Lap Wear Indicator Color
18 RF turns light green
22 RR turns light green
24 LR turns light green
28 RF turns yellow
30 LF turns light green
Tire Temperatures (°F)
LF RF
Lap O M I I M O
7 193 188 186 222 218 214
15 191 186 184 215 211 207
30 189 184 181 218 216 210
LR RR
Lap O M I I M O
7 205 199 190 216 205 199
15 200 193 185 203 193 188
30 199 193 184 207 198 192
Note: All tire temperature readings were taken at about the 1/3 distance mark of the backstretch.
Comments: Only minor improvements in lap times. Lap time consistency did improve, particularly at the end of the run. The tire temperatures on the rear picked up on average by about 10°. But is this enough? How even should the tire temperatures be? Getting the car slowed down going into Turn 1 without seeing the rear end out the passenger window is still a challenge. Must pump the brake.
Julian Data >>
Here's the reason why I wanted you to adjust the RARB and Rear Weight... during the first run you told me that the car had a hard time turning the turns I am concentrating in the middle first. Now by no means are these adjustments final since you start playing with other areas, things will change.
My goal for tire temperatures at this particular track range from 200-210º. The setup in it's present state isn't doing that right now.
So let me surmise how the car is feeling now:
- The car is looser in the turns.
- Entering Turn 1, the rear end wants go around.
- At the middle of the turn, you are tad loose or a bit neutral?
- You didn't state how the car felt coming off the turns.
- OK, so you are loose going into Turn 1.
Here's what I want you to change:
- RR: Rebound: drop it down to 200
- Decrease grill tape by 5%, trying to lessen the front downforce going into the Turn.
- Notice how I haven't told you mess with the Brake Bias adjustment. Why? Because the longer the green run and as the fuel load lightens, under braking, the car is really going to push going in if you added more bias to the front.
Tire Wear: I don't like how fast the RIGHT sides are wearing. In order for the right sides to last longer, we need to soften rates, which I might add might drop the tire temperatures since there's less force onto them.
We will start with the tire PSI first. Why do the tire pressures first? Here's why, tire pressures give the most influence in finding which direction to head. Remember a tire is basically part of the suspension as its sidewall flexes thus giving you another spring rate adjustment. So with that all said, let's drop the RIGHT side tire pressures by 2 psi as a starting point. I know this is a big drop but it will tell me, which way to go on feel and tire temps.
From this point on, please start running the car up to 35 laps. (Ed. Since we're working on a race setup, Julian later suggested just running a full fuel run)
Timothy Bennett >>
Here are some additional comments I have concerning how the car feels:
- The car is definitely looser through the turns than the first run.
- Regarding the rear end wanting to go around entering Turn 1 - Yes, if you brake and I'm easy on the brakes. Pumping minimizes the loose condition. This isn't so bad during the first 1/4 of the run, but beginning about lap 11 or 12 you have to start tapping the brakes.
- The setup is neutral in the middle of the turn.
- Coming off the turns this is kinda tricky. Mostly it feels pretty good. Before the adjustments, I was fighting a push off the corners and having to feather the throttle or just plain wait longer before getting back on the gas. After these adjustments, that push has mostly went away. However, it does seem to still happen on some laps and I'm not sure if it's the setup or the driver. One thing about this push, if I'm hard on the wheel keeping it out of the outside wall, I suddenly find myself taking an off road adventure through the front stretch grass or, worse, kissing Mr. Inside Wall on the back stretch.
I'll make the suggested adjustments and run a full fuel run.
OK... I dropped the RR rebound to 200, decreased the grille tape by 5%, and reduced the right side tire pressures by 2 psi each. I then ran 69 laps.
Here are the results:
Lap Times (sec)
Best Worst Average Std Dev Variance
start (laps 1-23) 24.177 25.464 24.416 0.275 0.075
middle (laps 24-46) 24.046 25.510 24.374 0.319 0.102
end (laps 46-69) 24.316 30.067 24.834 1.157 1.338
total (laps 1-69) 24.541 0.725 0.526
1/4 Run @ Lap 18 - What can I say... TIGHT. Tight entering the corner. Tight in the middle of the corner. Tight exiting the corner. Did I mention it the car feels tight through the corners?
1/2 Run @ Lap 36 - The car loosened up some during this part of the run though I wouldn't categorize this setup as "loose", it just wasn't as tight as in the first part of the run. This part of the run produced my fastest laps, though I never broke 24 secs. It was easier to get into and off the corners.
End of Run @ Lap 69 - Seems like in the last half of the run, the car picked up a tendancy to pull to the right down the backstretch. Also, the car was VERY VERY loose braking into Turn 1, particularly the last 10 laps of the run. At lap 61, the car broke loose under "light" braking entering Turn 1. I got completely sideways in the middle of the turn. I saved it and kept it out of the wall, but light pumping on the brake was absolutely necessary the last part of the run.
Tire Wear
Lap Wear Indicator Color
21 RF turns light green
28 RR turns light green
30 LR turns light green
31 RF turns yellow
34 LF turns light green
40 RR turns yellow
45 LR turns yellow
48 LF turns yellow
61 RF turns orange
Tire Temperatures (°F)
LF RF
Lap O M I I M O
18 173 176 176 209 205 209
36 176 180 179 217 213 217
69 162 164 164 193 191 192
LR RR
Lap O M I I M O
18 184 183 173 188 183 177
36 187 186 175 191 186 180
69 176 175 166 178 174 168
Note: All tire temperature readings were taken at about the 1/3 distance mark of the backstretch.
Comments: Lap times dropped dramatically (1/2 second on average), presumably due to the decrease in the right side tire pressures. The changes to the grille tape and RR shock rebound I believe did help with the "loose under braking" condition entering Turn 1. The condition did return with a vengeance the last 10 laps of the run. On lap 61, the car suddenly and without warning broke loose under "fairly light" braking. I got completely sideways through the middle of the corner, but managed to save it and keep it out of the wall. But by far, this setup was pretty tight all through the corner for the majority of the run.
Julian, can you comment a little more on why the tire pressures give you information on which direction to head? Also, what are the different directions you're trying to determine?
 
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