The Porsche 911 is possibly one of the most delightfully stubborn cars ever. Porsche has retained the 911's rear-engine layout since it evolved from the KdF-Wagens back in the 1930s. As much as I love an ass-engine, there are times when it may not be the best solution, and now even Porsche seems to agree, at least on their new GT racer.
The 911 RSR is a GTE and GTLM class racer, and is Porsche’s premier racecar based on one of their production cars—in this case, the 911.
The current version of the 911 RSR is as rear-engined as any production 911. The new version, seen in testing on the Sebring road course, is showing a number of visual clues to suggest that the engine has done a bit of forward migration.
The most obvious difference is that the car now lacks a real rear window, with that area now filled with a panel full of vents and air intakes. That’s pretty much right where you’d want to be extracting and sucking air in if the engine was residing ahead of the rear wheels.
Also, if you look under the rear of the car, you can see a much larger air diffuser, and a new exhaust system featuring two pipes. If the engine was still hanging out behind the rear axle, all that area would be taken up with those six horizontal cylinders.
That bigger diffuser may be the main reason this layout change was wanted, since new regulations allow for a much larger rear diffuser that just wouldn’t have been possible with the engine in the way. This looks to be a more aero than weight distribution-inspired decision.
Is Porsche just flipping the drivetrain 180 degrees to get the heavy bits in the middle? That’s how the very first Porsche ever was created, using a flipped Volkswagen drivetrain, and that’s how almost any mid-engine VW (including the VW-Porsche 914) did it.
Based on the nature of the exemption Porsche got to move the engine in the 911, I think the 180 degree flip seems the most logical approach:
The technical Exemption enables the engineers not to place the gearbox as far in front but behind the engine. The block therefore moves slightly towards the center, which has a positive effect on the balance. The Porsche 911 RSR would thus be no rear-engine car more but a so-called rear-mid-engine vehicle.
It seems unlikely that this mid-engine configuration would carry over to a mid-engine production 911, because that’s sort of the role of the Cayman and Boxster. I think for many, the whole point of a 911 is that it is rear-engined, after all.
Still, on the track, it looks like Porsche is grudgingly going to try and play nice with physics, if they have to.