推 Scape: 今天剛出來一則影片,Model 3P換了Cup2胎、改了剎車,在 06/08 00:34
→ Scape: 北京金港賽道跑1:13.789,側向最大1.8G 06/08 00:35
→ Scape: 這應該不算正式記錄,不過可以看到換胎之後差很多 06/08 00:36
→ Scape: 2018年時Giulia Quadrifoglio在同一賽道跑出1:15.841 06/08 00:37
推 Scape: Model 3金港賽道影片:(微博) 06/08 09:33
→ Scape: https://www.weibo.com/2124878297/J5zrF70X3?type=comment 06/08 09:33
呃~基本上市售車不太可能有過彎側向1.8g的表現
https://i.imgur.com/NTrmReu.jpg
主要由四顆輪子的側向力提供車輛過彎時所需的向心力
當然會因為輪胎側滑角(tire slip angle)
所以實際提供的向心力會是四顆輪子乘上該輪側滑角的分量總和
1.8g過彎,代表向心力是車重的1.8倍
假設以最理想的四輪重量平均分配的條件,那輪胎的側向摩擦係數要有1.8
一般市售車配胎,側向摩擦係數約略0.8~0.9左右
就算是頂級街胎,側向摩擦係數了不起就是1.2~1.4左右(也許我還有些高估了)
https://i.imgur.com/Xd0wLY2.jpg
https://i.imgur.com/egWpcvt.jpg
輪胎載重增加,雖然能提供的側向力會增加
但最大摩擦係數會越來越小
也就是若同輪胎下若車重增加,也會不利於過彎表現
https://i.imgur.com/WOsOPjZ.jpg
那為啥像方程式或有些單艙賽車的側向G值可以到2以上
因為除了車重外,還依賴空力提供的下壓力
輪胎vertical load增加,能提供的側向力自然增加
量測到過彎1.8g
很大可能是儀器安裝時並沒有固定穩
最後附上Focus RS從PSS換成Cup2的表現
Ford Focus RS with Michelin Pilot Sport Cup 2 Tires
https://reurl.cc/oDWoM5
The Focus RS comes from the factory on capable Michelin Pilot Super Sport
radials. Like our Lightning Lap car, this example came with a $1990
wheel-and-tire package consisting of a specific 19-inch forged-aluminum wheel
and as racy a tire as you can put on a street car, the Michelin Pilot Sport
Cup 2
Stopping from 70 mph takes 154 feet, which is only four feet shorter than a
Super Sport–shod RS, but lateral acceleration jumps from just below 1.00 g
to 1.04 g
This RS’s accelerative performance—zero to 60 mph in 4.6 seconds and a
13.4-second quarter-mile—is unchanged
70mph下煞停距離:158 feet -> 154 feet
側向加速度: 1.00 g -> 1.04 g
加速性能:不變
從PSS換成Cup2,側向加速度只提升0.04g唷