Porsche has been extremely guarded about what’s behind the black louvered panel that hides the new 911 RSR’s engine bay. Under that panel, Porsche made the best use of the 911's meager backseat space by stuffing in a 510-horsepower endurance racing flat-six engine to make the RSR they use for legendary races such as Daytona and Le Mans.
Here, you can see a big firewall that separates the engine bay from the cabin of the car. The roll cage extends into the engine bay just as if it were the 911's backseat, however, its only passenger produces the 510-horsepower, 991-generation 4.0-liter engine that makes it go. Of course, this also necessitates the use of a rear-view camera as well as a collision avoidance system inside the cabin.
The reason for this change, as we know, was to accommodate a gigantic rear diffuser that was recently allowed for GTE-spec race cars. That diffuser sits where the bottom of the 911's rear engine usually sits.
All of the changes were sparked by the need to fit in that rear diffuser and catch up to the rest of the cars the 911 RSR competes against. The front aero was changed to balance out the car. The rear wing moved to a top-mounted design. More quick-change parts make things easier to access and get to.
Then there’s the engine, that went to what Porsche calls a “rigid valve drive” with a solid lifter camshaft to eliminate the extra weight of a hydraulic system. It’s a preview of what goes into the next GT-series road cars, like the 911 GT3. Its exhaust, which is routed through that meaty diffuser, has separate pipes now, changing the sound.
Going mid-engine has had a number of benefits, like more manageable tire wear from distributing the load more evenly across all the 911's wheels. The window of tuning—as in, the range of set-up options where the car still works well—is also a lot larger, per the Porsche representative I spoke with.
I was relieved to hear from Porsche crew members that one signature feature of the 911 RSR didn’t go away with the move to a mid-engine layout: its ability to run well in the rain. It wasn’t annoying or snappy, which is good.
Other, less obvious changes were safety upgrades made in response to driver Richard Lietz breaking his arm at Virginia International Raceway in 2014. There was enough cockpit intrusion in Lietz’s crash that Porsche opted to move the new RSR’s seat 50 mm inboard and fix it in place, such that the geometry of the roll cage will be ideal for whoever sits in it. The pedals and the steering wheel now move instead to accommodate different-height drivers.
Mostly, though, I’m jealous of this 911's rear passengers. The newest, most state-of-the-art flat-six engine beats whiny people any day.