Mystery Of The Missing Vent: Why Does the Porsche 911 GT3 RS Get More Air While The Standard GT3 Doesn’t?

Why The GT3 RS Has A Side Vent But The GT3 Doesn’t

The first stop was Porsche’s press releases for both track-bred cars. Great for drool-worthy details and specs for any Porschephile, but fairly light on the "why" behind design choices. No luck there. Digging deeper, I hit up my favorite car review websites (I’m not going to take names here). Several publications mention the extra air vent on the RS but none explicitly explain why the GT3 lacked it. Here are the two theories, that I initially came up with for the missing side vent on the GT3:

Power Hungry? Maybe Not

The web mostly thinks the side air vent on the RS feeds more air to the engine for more power. On paper, this makes sense – more air usually means more efficient combustion and potentially more horsepower. But the standard GT3 already has a hefty 502 horsepower, which is pretty close to the GT3 RS’ 518 horsepower. After all, both models pack the same 4.0-liter naturally aspirated flat-six engine. So I figured, maybe extra power isn’t the reason.

Cooling Under Pressure?

Another possibility is that the additional side vent on the RS is for enhanced cooling. During hard sessions at the race track, things like engine oil and brakes run at significantly higher temperatures. The GT3 RS, being the track-focused animal that it is, might require extra airflow to keep these components cool. This theory is supported by the fact that the RS also features enlarged air vents in the rear bumper possibly for heat extraction, further suggesting a focus on improved cooling. But this wasn’t the case either, as I later found out.

Here’s The Answer: Aero Is King

But here’s the answer I found! I actually went down a rabbit hole and watched a deep dive near hour-long presentation on the Porsche 911 GT3 RS, and the side vent is not for engine combustion, but it’s purely for aerodynamics. As you can see in the graphic above, Porsche clearly defines the function of the opening in the rear quarter panel, a.k.a the side vent: which is to create a vacuum and reduce air resistance at the rear, through targeted airflow.

The Porsche GT3 RS boasts more downforce compared to the standard GT3: A whopping 860 kg (1,895 pounds) of downforce at 177 mph. In simpler terms, the GT3 RS is capable of generating more than three times the downforce of the standard GT3, which translates to significantly better grip and stability during high-speed cornering on a track.

This theory is further reflected in the top speeds of both models. Where the standard GT3 is capable of a higher top speed of 197 mph, the GT3 RS with its slightly lower top speed of 184 mph will be quicker around a race track, as it produces more downforce. The nearly $60k premium that you pay for GT3 RS truly pays dividends on the race track.

This makes even more sense when you consider the bodies of these two cars. After digging through the forums, I learned that the 911 chassis was available across three platforms, Narrow, Medium, and Large until the 991 generation. With the 992.1 generation, Porsche has done away with the original narrow body, only leaving two available platforms. So what used to be the old medium chassis is now the new narrow-body chassis. I know, confusing right?

The current 911 GT3 uses the Carrera’s NarrowBody, which lacks the space for the side vent. The GT3 RS, however, utilizes the wider body of the Turbo, which has the space to include the vent. But that’s not all, besides that side vent, the GT3 RS features a far more aggressive body with even more aerodynamic features in the front fenders, under the body, and a much bigger wing and rear diffuser, all contributing to the higher downforce numbers I touched upon earlier.

While Porsche hasn’t officially confirmed this, based on my research and the video, the theories above are strong reasons for the lack of the side vent on the GT3, with aerodynamics being the confirmed function for the RS. So, the next time you see a 911 GT3 RS with that gaping maw, remember, that it’s not just for looks. It plays a crucial role in generating downforce for superior track performance.