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Vidéo – Une Porsche 911 Turbo S remonte une piste de ski

Un jeu d’enfant pour un tel bolide !

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Porsche 962 Wastegate Nirvana at Laguna Seca

Skylar Robinson, son of famous American racer Chip Robinson, puts on a show in a raucous Porsche 962 making a peculiar series of noises. The 2.8-liter, twin-turbo six in the middle of his IMSA GTP racer squeaks and roars, and when the full 750 horsepower arrives in one big lump, it fires the car down Laguna Seca’s straighter sections at a pant-wetting pace. More exciting than the raw speed, going by the comments beneath the video, is the distinct « choo-choo-choo » noise echoing in the cabin, often referred to as ‘wastegate chatter’.

What’s A Wastegate?

The wastegate is, essentially, a valve which diverts exhaust gasses away from a turbocharger to keep it from spinning too quickly and, therefore, increasing boost pressure too much. The valve is controlled by a pressure actuator, which is linked to the turbocharger, and the wastegate is held shut by a spring inside the actuator. When the boost pressure exceeds the pre-set maximum, it compresses this spring, progressively opening the wastegate to bleed off excess pressure, regulating the impeller’s speed, and ensuring the turbocharger and the motor aren’t damaged.

How Does it Differ From Compressor Surge?

Though the fluttering noise made by this 962’s engine might be referred to as wastegate chatter, it is technically known as compressor surge. When the throttle plate closes, the combination of the lack of airflow, consequent rise in pressure, and the high speed of the compressor cause the compressor blades to effectively lose their “grip” on the air. Aerodynamically speaking, the air separates from the back of the compressor blades, allowing some air to escape back out through the compressor. The resulting pressure drop in the intercooler piping allows the blades to “grip” again which, under the residual momentum of the turbo, will increase the pressure and the cycle repeats. This is what causes that remarkable flutter sound that will crack a smile across the stoniest of faces.

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Porsche : les cinq voitures les plus légères

VIDEO. Découvrez les cinq Porsche les plus légères de l’histoire.

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Porsche Says These Are Their 5 Lightest Models, Kind of…

In an era of ballooning waistlines for ordinary cars, Porsche’s commitment to lightweight stands out. In 1991, a new Volkswagen Jetta GLI 16v tipped the scales at a bit under 2,500 lbs. Today, a new Jetta GLI weighs about 700 lbs more. By contrast, a 1991 Porsche 964 Carrera 2 with a manual transmission is just over 100 lbs lighter than its modern counterpart. Indeed, a new GT3 and an RS America are separated by under 70 lbs. By modern standards, either is a flyweight. Neither car comes close to cracking the top 5 lightest Porsche models of all time.

To be fair to the 1.5 ton GT3, most of the Porsches in the Top 5 are dedicated racecars. Only the Carrera 2.7RS Sport is a traditional road car, and the 356 Sport Leicht is about as stripped out as early 50s GT racers come. The 2,150 lb (975kg) Carrera 2.7 RS Sport is not only the heaviest of the bunch, it’s the heaviest by a substantial margin. Though the Carrera RS is one of the lightest 911s, it weighs as much as the two lightest cars on the list combined.

The list does contain some glaring omissions, and isn’t a good reflection of the actual Top 5 lightest Porsche models. Most production 356s weigh in at under 975kg, save for the C convertibles; the heaviest of the lot. The mighty 917K tips the scales at 800kg, easily ousting the Carrera 2.7 RS Sport from the Top 5. Indeed, at 850kg an IMSA GTP spec 962 also undercuts the apparently-porky 2.7 RS.

While the 911 Carrera 2.7 RS Sport is a remarkable machine, it’s pretty clear that anything over a ton isn’t going to cut it in Porsche circles. Though Colin Chapman is credited with coining the phrase « simplify and add lightness, » Porsche managed to implement that philosophy, and build durable, reliable cars.

Can you guess the lightest car on the list before watching the video? Let us know your guess in the comments!

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Four Porsche 911 GT3 R tackle the ADAC GT Masters

Three customer squads field a total of four Porsche 911 GT3 R racers in the 2018 ADAC GT Masters. Contesting the “Super Sports Car League” for the first time is the reigning world endurance champion and two-time Le Mans winner Timo Bernhard.

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