Porsche is holding back its Cayman for the 911, but not in the way you think
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It had long been speculated that Cayman isn't nearly as good as it could be because Porsche needs to save face for the 911.
On the face of it, this conspiracy theory isn't without the backing in fundamental physics. However, it is not quite as simple as it looks. Let me explain.
50:50 Weight Distribution
As many car manufacturers like to boast about the 50:50 weight distribution of their vehicles, the fundamental way a car behaves near its limits is dictated by its weight bias.
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What is 50:50 weight distribution, exactly? Well, it means that the front and rear axles bear the same amount of weight, thereby making it possible for the Miata in the picture above balanced.
Below is Motortrend's Dimension data for 2017 Cayman S and 2020 992 Carrera S:
End of story, right? Cayman's 44:56 weight distribution is clearly superior to the 36:64 of the 911's. Well, almost, but not quite.
Your 50:50 is not the same as my 50:50
Audi RS3, credits to Audi USA
Let's take a little detour out of Porsche and talk about Audi. For ages, Audi's performance RS cars have been criticized for their tendency to understeer. Let's take the RS3 for example. The commonly blamed factor is its 58:42 weight distribution, which means that it's overwhelmingly nose-heavy. But what if I load up its trunk with, say, manure?
Theoretically this could yield a 50:50 weight distribution, and that it would be the easiest fix to a fundamentally handicapped vehicle dynamic characteristic. So why hasn't this been implemented? Well, it's because the weight is hanging way off to the front of the front axle.
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By doing so, it will increase the rotational inertia, making the vehicle less prone to turn. In a way, Porsche's 911 is like the Audi RS3, but with its engine hanging over the back. You can't simply load up the 911's frunk to make it handle better because you can "achieve 50:50 weight distribution".
To help you visualize this, here's a high school physics lesson that you are probably familiar with:
As you can see, as the instructor pulls the masses in, his angular velocity (the rate at which he spins) increases, which is analogous to how a car is more eager to turn with its mass closer to the center of the vehicle.
Unlike the 911, Cayman has its engine in front of the rear axle, reducing its rotational inertia and thereby making it more eager to turn. Even Porsche's 911 RSR racer, albeit being a 911, has its engine in front of the rear axle, just like the Cayman.
911 RSR, credits to Porsche
And the racing drivers in Japan, including Keiichi Tsuchiya himself, took a Cayman and 911 to the Gunsai Touge for a face-off. They also mentioned how Cayman felt more nimble in the winding mountain roads. [P.S. English caption available]
So, is Porsche deliberately holding back the Cayman for the 911? Very likely. But we should still give Porsche much credit for persevering for the past half a decade to make such an unconventional engine layout work, along with the unique driving experience that results from it.