Porsche 911 991.2 (2015-2019) review - Engine and transmission

Engine and transmission

The 2981cc twin-turbocharged flat-six engine is the first forced induction unit ever to be fitted to a 911 Carrera. In the entry-level model it produces 365bhp at 6500rpm and a strong 332lb ft of torque between 1700 and 5000rpm. That mid-range torque output gives the Carrera a vastly more muscular feel than the rather peaky normally aspirated engines of old. 

Although tractability has been much improved, the new turbocharged engine has lost some of the character and verve of the outgoing powerplants, but in terms of throttle response and linearity of power delivery they rank among the very best forced induction engines anywhere – and you still get to enjoy that characteristic flat-six sound, which is more than can be said for its smaller Boxster and Cayman siblings these days…

The same engine is used in the Carrera T with an unchanged power output, but you do get a fruitier sports exhaust, and with a small weight drop you do get an equally small performance improvement. The Carrera S in contrast uses the same 3-litre unit, but with power lifted to 414bhp at 6500rpm, while torque is now rated at 369lb ft between 1700 and 5000rpm. For reference, the superseded normally aspirated Carrera S made do with 325lb ft of torque at a heady 5600rpm.

The seven-speed manual gearbox is now much improved over the slightly notchy early iterations with a slick, precise and mechanical throw that gets close to matching the company’s delightful six-speed manual. Shifting gears yourself adds a welcome layer of interaction, which counts for a lot in a car that can be short on engagement at low and medium speeds. 

The optional twin-clutch PDK gearbox, meanwhile, is the more popular transmission option. It’s supremely refined and smooth in automatic mode, while manual shifts using the steering wheel-mounted paddles are all but instant. For sheer performance, fuel economy and daily usability the PDK gearbox wins out, but for driver engagement the manual remains the gearbox of choice. 

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All Carrera models other than the four-wheel drive-only Targa can be mated to either a rear-wheel drive or all-wheel drive transmission. 

Normal aspiration lives on in the hardcore GT3 and GT3 RS models. The former uses a 3.8-litre unit that develops 469bhp at 8250rpm with 325lb ft available at 6250rpm. The GT3 engine is one of the most exciting modern performance car engines on the planet with a truly electrifying surge through the final 1000rpm to the 9000rpm redline. 

The RS uses a longer stroke version of the same engine to displace 4-litres. That lifts power to 493bhp at 8250rpm and torque to 339lb ft at 6250rpm, although the longer stroke has reduced peak engine speeds to 8500rpm. The dash to the redline is less extreme in the RS than it is in the GT3, but the 4-litre remains an intoxicating power unit. Both models are PDK-only. 

The Turbo models are also more powerful than ever – 533bhp and 523lb ft from 2250 to 4000rpm (on overboost) for the Turbo, while the Turbo S boasts 572bhp and 553lb ft (at the same engine speeds as the Turbo, also on overboost). 

These 3.8-litre units feel very different to the Carrera’s 3-litre twin turbo engine. Rather than very linear power delivery with no discernable step up in power throughout the rev range, the higher capacity engines feel less energetic in the lower reaches, while delivering a much more forceful hit in the back from 3000rpm. The Turbo models also have a less effervescent top end than the Carreras.

For the first time, the Turbo S uses bigger turbo compressors than the Turbo.