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The Porsche 911 has changed quite a lot over the years, yet in all its iterations, it’s always followed the same philosophy: rear-wheel drive with the engine at the back. That could be why many Porsche purists had mixed reactions when the German automaker announced its latest hybrid-powered 992.2 Carrera GTS. Spoiler alert: it’s not the same performance-hybrid system you’ve likely seen in other sportscars.
Turbocharging has long been one of the most common power adders for performance vehicles; it’s a great way to increase power without significantly tanking fuel efficiency. Turbos have changed dramatically since their introduction to production vehicles in 1962, but Porsche’s T-Hybrid system in its latest 911 GTS really is a true game changer. Here’s why.
Why Go Hybrid?
Porsche purists will likely ask why the brand opted to go hybrid at all. And they’re not wrong for wondering. The previous 911 GTS was no slouch, with over 450 horsepower, motivating it to reach 60 mph in just 3.1 seconds—in the Carrera 4 GTS with PDK. Instead, Porsche went hybrid because of environmental restrictions, as the previous internal combustion engine had reached its maximum potential.
Euro 7 emissions restrictions, which go into effect on July 1, require engines to run a perfectly balanced air-fuel ratio all the time—sometimes referred to as lambda 1. Running within these parameters limits the emission of hydrocarbons, as it’s the most efficient combustion process without the excess fuel from a rich mixture or excess air from a lean mixture. While this is great for efficiency, making the same amount of horsepower while maintaining lambda 1 is significantly more challenging.
Porsche and many other performance automakers would normally be able to enrich the fuel mixture at full throttle to suppress detonation—sometimes called “knock” or “pre-ignition” in turbocharged engines. Detonation is bad, as it’s an uncontrolled explosion inside the engine that can cause severe damage, including melted spark plug electrodes, cracked piston rings, and even melted/cracked pistons, among other things. Without the ability to adjust the air-fuel ratio, retarding the ignition timing (making the spark happen earlier) is one of the only remaining ways to control detonation.
This leads to a considerable loss in horsepower, meaning the previous engine was maxed out in its current configuration. That’s why Porsche sought to use a hybrid system to counteract the losses from the new regulations.
It’s just not the hybrid system you’re probably used to seeing.
What Is T-Hybrid?
Courtesy Porsche
As the name suggests, Porsche’s T-Hybrid system assists the turbocharger with an electric motor instead of using an electric motor to drive the wheels, as we’ve seen previously. The new single-turbo setup replaces the old twin-turbo setup, assisted by a 27-hp electric motor mounted within the turbo. The electric turbo brings plenty of advantages besides merely recouping the power lost from emissions restrictions.
First and foremost, we can’t overlook the fact that T-Hybrid effectively eliminates turbo lag. Dyno charts compare the power curves of the two engines, and it’s clear that the new motor is much more muscular; it’s able to produce its quoted 450 lb-ft of torque almost instantly at 2,000 RPM, while you’d have to wait a couple seconds for the conventional 3.0-liter twin turbochargers to spool up.
Courtesy Porsche
T-Hybrid also brings considerable weight savings over traditional hybrid systems. It probably doesn’t come as a surprise that it takes much less power to assist a turbocharger than to motivate the wheels of a car. The entire system is powered by a 1.9-kW lithium-ion battery mounted near the front of the car, which at 60 lbs isn’t much heavier than the 12V lithium-ion battery that powers the rest of the vehicle’s electronics when the engine is off. For context, Porsche says the complete package adds only 103 lbs to the curb weight compared to its predecessor.
Porsche’s T-Hybrid system is fitted to a larger 3.6-liter flat-six engine instead of the previous 3.0-liter twin-turbo flat-six. With a strong diet and clever engineering, Porsche was able to make the new engine 40 lbs lighter (not to mention smaller) than its predecessor despite having significantly bigger displacement. The new intake manifold was repackaged to carve out the roughly 4 inches of vertical space needed for the new hybrid components; along with adding power, the new electric motor is able to replace many traditionally belt-driven engine accessories like the alternator.
If you’ll allow us to be amazed for a second, the electrically assisted turbocharger doesn’t need a conventional wastegate either. Traditionally, these divert excess exhaust gasses away from the turbocharger to stop it from spinning too quickly and causing damage. As the turbo nears its 125,000 rpm redline, the electric motor inside acts as a generator to limit its speed—producing up to 15 hp. Porsche says this juice is then used to assist the engine at high revs (from 5,700 to redline), where the flat-six is outside of its optimal powerband.
What Does the Future Look Like?
Leave it to Porsche’s army of big foreheads in engineering to completely transform what hybrids mean to car enthusiasts. They’ve reaped the benefits of traditional performance hybrids—augmenting internal combustion power by driving the wheels—without adding significantly more weight. However, that’s not without adding significant cost.
It’s no surprise that the new and improved GTS would punch a bigger hole in your wallet. The mid-level 911 now starts at $166,895—$14,000 over its predecessor. That’s not an insignificant amount of money, but we have to understand that technology doesn’t come for free. We’ve yet to drive the new 911 ourselves, but our friends at Car and Driver have proved that there’s a considerable return on investment.
For context, the new GTS has reportedly lapped the Nurburgring Nordschleife 8.7 seconds faster than the outgoing 992.1 GTS. Spoiler alert: that’s fast. Really fast.
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