13 My Take On The Porsche 2022 911 GT3

Cover for 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:

https://tirepressure.com/porsche-911-tire-pressure#2021
https://www.caranddriver.com/reviews/a36164987/2022-porsche-911-gt3-drive/

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

1w ago by NatsM
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SpeedKing  1w 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?

 

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196ss  1w ago

As far as I know, 991.2 GT3 RS had a manually adjustable rear wing angle. Therefore, top speed and maximum DF are achieved with different settings. Drag coefficient is also different in that settings. I'm not 100% sure, but probably the same thing is with the 992 GT3.


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SpeedKing  1w ago @196ss

The rear wing was in the middle setting according to JB. His wind directions were wrong because i checked time and date historical weather conditions for Cape Canaveral . The wind was 7 mph and blowing from NE to SW at 50 deg so it actually had a slight tailwind with the DA at approx 1100ft so that would equate to approx sea level air with no wind. Gives more weight to my claim that it cannot achieve 197 mph.

https://www.youtube.com/watch?v=7JdBaTZ1v34&t=12s


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196ss  1w ago @SpeedKing

Yes, perhaps moving the wing to the lower position would add 3-5 mph, but 10 is doubtful.


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NatsM  1w ago

Hi there again! Thanks for the feedback. First off, this calculation here is from the 2022 Porsche 911 GT3, NOT the same as the 2019 Porsche 911 GT3 RS that was on YouTube. You probably confused the two. Second, if you pay close attention to what the "weather conditions" say below the video AND the "testing conditions" on the video itself, the wind direction is not the same — the "weather conditions" say the wind is from the southeast at 3 PM, while on the "testing conditions" on the video itself says the wind is from the southwest! That alone is confusing and not helpful. Anyway, whether southeast or southwest, the runway itself is actually running northwest to southeast based on Google Earth. So, more or less, it's more of "headwind" which will slow the car down, right?

I may have a simple explanation about the discrepancy you guys are saying. I will try to explain in detail as best as I can regarding the top speed of the 2019 Porsche 911 GT3 RS that you compared it with the 2022 911 GT3 version that I used here. Please pay close attention to everything I say or include. First off, according to Porsche's claim, the 2019 GT3 RS has a top "track" speed of 193 mph, which may or may not be its actual or true "top" speed -— https://newsroom.porsche.com/dam/jcr:e00c2789-42c7-4dab-a818-a732003194b0/2019_911_GT3_RS_Technical_Specifications.pdf.PDF

Second, again on YouTube — https://www.youtube.com/watch?v=7JdBaTZ1v34, under weather conditions, 2 times were listed: one at 10 AM, and one at 3 PM. However, on the video itself, both 10 AM and 3 PM "testing conditions" are slightly different, but it's okay. It wouldn't affect much the outcome. BUT, on the video itself, the top speed run was actually done at about 4 PM, not 10 AM or 3 PM. Now, since Titusville is just about 7 miles to the west of the runway, I would rather use its weather condition at 4 PM. I don't think the 2 locations would have very different weather condition, right? Going to timeanddate.com for Titusville, Florida on March 19,2019, you will get the weather condition at the time. Then inputting the temperature, humidity and pressure — https://www.omnicalculator.com/physics/air-density — you will get the air density of 1.193 kg/m^3 which we will use. The other specs and parameters are from the websites below. Again, I will use my own method and equations.

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

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

2019 Porsche 911 GT3 RS

Where:
Hc = Horsepower 520 (527 PS)
EP = 8,250 rpm
Tp = 346 lb-ft @6,000 rpm -> 469 Nm
p = 1.193 kg/m^3
Af = 23.03 sq ft -> 2.14 sq mt
Cd = 0.36
S = 195.51 mph @33.0 psi
Wt = 3,260 lbs including driver -> 1,478 kgs
Pf = 0.95675
Cr = 0.0507 @33.0 psi

520 = (0.00000556517x1.193x23.03x0.36x195.51^3 + 0.0026667x0.0507x195.51x3,260)/0.95675

Finally, at the time around 3 PM, according to YouTube — https://www.youtube.com/watch?v=7JdBaTZ1v34, a 9-mph wind was coming from the southeast or southwest whatever, and the car was running north to south on the runway (actually the runway runs northwest to southeast — 196 mph minus 9 mph "headwind" = 187 mph. BINGO again? Thanks for the time.

 

https://newsroom.porsche.com/dam/jcr:e00c2789-42c7-4dab-a818-a732003194b0/2019_911_GT3_RS_Technical_Specifications.pdf.PDF

https://tirepressure.com/porsche-911-tire-pressure#2019

https://www.omnicalculator.com/physics/air-density

https://www.timeanddate.com/weather/usa/titusville/


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SpeedKing  1w ago @NatsM

I need to correct some of your claims. Firstly i was well aware that you used the new GT3 and not the GT3RS i referred to. The reason i used the GT3RS as an example was due to the close similarities between the two cars. At the Nurb record runs the acceleration and top speed of both cars was almost identical so it's a reasonable starting point to use as a comparison.

Secondly i clearly stated that the wind direction info on the video was incorrect and i've looked at both the Titsville(pun intended) and Cape Canaveral(south) and contrary to what i posted earlier it was pretty much a crosswind coming from the east heading west for both weather station locations so NO headwind.

I clearly relied on an unreliable source for the top speed of 197mph so thanks for the link stating 193 mph. Anyway bottom line i'm not convinced that the new GT3 can do 198 mph but i'm sure we'll find out soon enough :)


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Cocobe  1w ago @SpeedKing

I guess a couple factors is that the top speed assumes a smaller attack on the rear wing. And that the Nurburgring back straight is uphill so it’ll look like cars too out sooner


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SpeedKing  1w ago @Cocobe

Another factor which i didn't mention was downforce for the 2022 GT3 and from what i can gather the previous model had 150kg at max speed and apparently this one has 150% more downforce which equates to 375 kg at max speed which is pretty much the same as the RS. I shouldn't have to remind peeps as to how much of an impact downforce can have on supercars, the Senna hits the wall at 204mph with over 800hp as a prime example. Therefore that further supports my view that there's nothing between them and hence why i can't see it doing 197/198mph.


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Cocobe  1w ago @SpeedKing

But to be honest, top speed stats for cars like these are quite useless anyways unless we get into the efficiencies of downforces. The Ford GT vs the C7 Z06 for example. Where one can go fast in a straight line AND fast around a bend, the other can only do one or the other, having to bolt on or remove aero elements

Gt3s were never meant to beat anything in its price range for drag racing or top speed


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SpeedKing  1w ago @Cocobe

Yes i agree that it's secondary to what this car is intended for and that is a fast track car which has top notch handling capabilities. That aside a theoretical formula supporting the 198 mph top speed claim has been made and it's open to scrutiny which is precisely what i've done :)


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NatsM  1w ago @SpeedKing

Howdy? Yeah, at times things don't add up. We all know theoretical or projected is not the same as actual. However, I do believe they can meet eye to eye if only the right and accurate inputs are fed into the theoretical. Math is an exact science. The only time it isn't is when you input wrong or inaccurate numbers. It just occurred to me that I probably shouldn't have joined this group since, as the title says, "fastestlaps" and not about fastest or top speed. It's mostly about lap times and acceleration times. Not that I'm not interested or don't know anything about them, but it's just that over time I got more curious about how fast a particular car can go and that I just leave lap times, acceleration times and trap speeds to others. I sometimes feel out of place. Anyway, we all want to know the outcome of whatever car in question for sure. Have a nice one.


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SpeedKing  1w ago @NatsM

Whether it be top speed, acceleration or lap times they all come under the one umbrella of performance. Theory has its place but i just wonder whether the drag/downforce aspects when using theoretical calculations aren't or don't differentiate sufficiently to get a more precise outcome. Thoughts?


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196ss  1w ago @NatsM

I don't know about everyone, but I always read your posts with interest. In addition, looking at the fierce battles of fans of Koenigsegg, Bugatti and Tuatara, you can't say that on this site everyone doesn't care about top speeds.
I think you could also use your formulas to calculate the acceleration. The calculation will be a little more cumbersome, because it is necessary to calculate the forces acting on the car at each instant in time, taking into account gear ratios and the power curve. I sometimes (lately rarely in fact) get carried away with such calculations, and often they give frighteningly close results in comparison with real tests. You correctly noticed that the laws of mathematics/physics are equally valid for the movement of any body, both bicycles and cars, as well as planets and stars. The only source of error in this case is incorrect initial data. This is unfortunately sometimes the case, manufacturers sometimes intentionally indicate incorrect information about the power, curb weight, aerodynamic characteristics of the car, etc. For example, the most egregious case was when I tried to calculate top speed of RUF CTR Yellowbird. Using the claimed power of 469 PS, I got an estimated top speed of 197 mph. In order to accelerate to 200 mph in 35.6 seconds and have a top speed of 213 mph (which was confirmed by tests), according to the calculation, it would take at least 590 hp. The use of a car with similar characteristics (claimed and tested) by Speedking is also a kind of approximation, same as your mathematical model. Comparing these results may provide interesting food for thought about the initial data, but certainly neither could give the final top speed value for the 992 GT3. This can give only a real test.
So please continue your researches, I think this is very interesting.