## 13 My Take On The Porsche 2022 911 GT3 First, using my own formulas and method then compared it to the standard method and formulas. Porsche claims a 198 mph top speed. Using these specs and parameters, it calculates to 204.25 mph using standard formulas. Way off. Now, my formulas and method calculated it at 197.82 mph — right there! I used 45.0 psi with the corresponding 0.0392 rolling coefficient for the speed and tire pressure, based on Porsche's recommended tire pressure:

Hc = (0.00000556517pAfCdS^3+ 0.0026667CrSWt)/Pf -> my formula

Pf = 5,252Hc/EpTp -> my formula

2022 Porsche 911 GT3

Where:
Hc = Horsepower 502 (509 PS)
EP = 8,400 rpm
Tp = 346 lb-ft @6,100 rpm -> 469 Nm
p = 1.204 kg/m^3
Af = 21.85 sq ft -> 2.03 sq mt
Cd = 0.34
S = 197.82 mph @45.0 psi
Wt = 3,222 (car); 165 (driver) = 3,387 lbs -> 1,536 kgs
Pf = 0.90714
Cr = 0.0392 @45.0 psi
P = 374,341 watts
n = 0.090

502 = (0.00000556517x1.204x21.85x0.34x197.82^3 + 0.0026667x0.0392x197.82x3,387)/0.90714

Using the standard power equation:

Pn = [0.5pCdAV^2+ Cr(M+Df)g]V, with 0.90 drivetrain efficiency and 0.015 rolling coefficient, the top speed translates to 204.25 mph.

374,341x0.090 = (0.5x1.204x0.34x2.03x91.31^2 + 0.015x1,536x9.8067)91.31
336,907 = (3,464 + 226)91.31
336,907 ≈ 336,934

However, if you substitute my "powertrain factor" of 0.90714 and rolling coefficient of 0.0392 to the standard equation, the top speed would be the same 197.82 mph — just as the manufacturer's claim! How can you get any better than this? ;-)

374,341x0.90714 = (0.5x1.204x0.34x2.03x88.44^2 + 0.0392x1,536x9.8067)88.44
= (3,250 + 590)88.44
339,580 ≈ 339,610 watts

4m ago by NatsM  SpeedKing  4m ago

Sounds great in theory however looking at the 2019 GT3RS with 520hp Porsche claimed its top speed was 197 mph. The only problem is that it pretty much hit the wall at 187mph on the JBPG test track. Porsche also claimed that the GT3RS had 144kg of downforce at 200km/h and 340 kg at max speed. The Weissach version had even more downforce so on that basis with the new GT3 having similar downforce i can't see how it can achieve 198mph. Thoughts?

### Timeline  Poopoo 1h

Wut      