July 15, 2024

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Built General Tough

75 years of auto motor und sport: Porsche 911 Turbo

The king is dead, long live the king. It’s been just seven months since Germany’s King of the Road gave up the crown to immediately join the noble ancestral line of investment classics. The Porsche Turbo, an acceleration potentate of truly legendary size, was a thing of the past.


Now the grief is over. At the Geneva Motor Show, faster than expected, Porsche presented the heir to the throne. But anyone who hopes for the beginning of a new era will be disappointed. The new Porsche Turbo looks like the face of its predecessor. The classic Turbo concept, cultivated since 1976, is celebrating its resurrection in Geneva.


75 years of AMS Porsche 911 Turbo 06 1990

HP Seufert

Big fin, wide flanks and two exhaust pipes, turbo look as usual.

Turbo as usual

Originally there was by no means a lack of new ideas. Inspired by the technology monster 959, the Weissach development team worked on titanic bi-turbo engines, tinkered with complex all-wheel drive systems and played with swinging body variants. Then, however, Ulrich Bez came along. The new owner of the Porsche development center, in office since October 1988, thinks little of costly experiments, but much of short development times and profitable model policy. Engineers, closely on the track of what was technically feasible, were whistled back, the ambitious plans stopped, the Über-Porsche disappeared briefly in the drawer.


Instead, Turbo as usual. “The gap left by the old turbo should be filled as quickly as possible,” argues Horst Marchert, the responsible development manager. And it did happen quickly, even if not as quickly as the early interview suggests. The starting shot for the new Turbo was given in February of last year, and production is scheduled to start next November.


75 years of AMS Porsche 911 Turbo 06 1990

HP Seufert

The basis remains the 3.3 liter boxer, but now with 320 hp and exhaust gas cleaned.

All wheel drive? Nothing

So it is not surprising that technical as well as stylistic innovations have been restricted to the inevitable minimum. The turbo-specific look follows the traditional pattern. Massive flared fenders, a huge rear wing and wider wheels set the Turbo apart from the weaker Carrera models of the new generation, whose characteristic features it also shares. The spoiler, which disappears discreetly in the rear when driving slowly, does not exist with the Turbo. As with its predecessor, there is space for the intercooler in the spoiler structure. Even a look into the interior reveals nothing new. The equipment corresponds to the current Carrera, more precisely to the Carrera 2, because a switch for activating the differential lock, characteristic of the all-wheel drive Carrera 4, is not found in the Turbo.

75 years of AMS Porsche 911 Turbo 06 1990

HP Seufert

View from below: Turbo rear shows new chassis and new exhaust.

What can already be guessed at, becomes apparent when studying the technical specification at the latest. Even the new turbo is satisfied with two-wheel drive, even turbo customers who are willing to pay extra are to be denied the advantages of all-wheel drive – a waiver that is difficult to understand given the drive technology already present in the Carrera 4. So why the Turbo, the most powerful and most expensive of all 911 models, without all-wheel drive? Turbo developer Marchert is not at a loss for an answer. “Our customers expect the driving machine that suits the active driving style,” is the official reason. The traction, but also stability-promoting four-wheel drive could scare them off. Of course, a finding that affects less the driving characteristics than the performance of the turbo is even more valid. If the aerodynamically inferior turbo (cw 0.36 instead of 0.32) had to drag along the at least 100 kilograms heavy all-wheel drive technology, it would be only marginally superior to the Carrera 2 here.


75 years of AMS Porsche 911 Turbo 06 1990

HP Seufert

The exhaust system (old below, new above) enables larger catalytic converters.

Old 3.3 liter turbo engine

But even without all-wheel drive, the turbo has already increased significantly. With complete equipment as standard, the dead weight slipped from the previous 1,335 to an impressive 1,470 kilograms, 120 kilograms more than a Carrera 2. For this reason alone, an accompanying increase in performance seemed necessary. However, the Porsche technicians did not have much leeway. The dictates of rapid, inexpensive development required the existing technology to be retained. So it stayed with the old 3.3 liter turbo engine. A turbo upgrade of the much more modern 3.6-liter of the new Carrera generation was discarded. Nevertheless, a demanding specification had to be met. Exhaust gas cleaning with a regulated catalytic converter with a simultaneous increase in output, improved response behavior and compliance with the strictest noise regulations were required – points which, at least in the periphery of the boxer engine, required intensive development work.

75 years of AMS Porsche 911 Turbo 06 1990

HP Seufert

The larger intercooler (far right) increases performance.

The new base, the Carrera 2, came in handy here. Allocated internally with the development number 964, this offers far better conditions for accommodating a high-throughput catalytic converter than earlier 911 models. The relocation of the oil tank in front of the rear axle creates space for the exhaust system, the rear silencer of which has recently been placed on the side of the engine. Its original space, across behind the rear apron, can now be used for a double metal catalytic converter.


Notable increase in performance

Another innovation shows how seriously they care about exhaust quality at Porsche. An additional catalytic converter, which is located in the bypass tailpipe together with a silencer, waits for exhaust gases that escape through the bypass valve when the maximum boost pressure (0.75 bar) is reached. The layout and dimensions of the turbocharger remain unchanged. A modified turbine wheel geometry should, however, accelerate the response behavior.

75 years of AMS Porsche 911 Turbo 06 1990

HP Seufert

A 911 interior as usual. Turbo-specific is limited to the scope of equipment.

The fact that there is also a noticeable increase in performance is largely due to the charge air cooler. This has been significantly enlarged, and the correspondingly cooler charge air enables the cylinders to be filled more intensively.


97 hp per liter

With that the possibilities were already largely exhausted. Motronic and double ignition, features of technical progress in the Carrera engine, are not granted to the turbo. A mechanical K-Jetronic injection continues to form the mixture. The previous high-voltage capacitor ignition (HKZ) is now replacing a more modern map ignition, which should have a positive effect on response behavior and consumption. Porsche expects consumption savings of around five percent on average. A more powerful alternator, a new design of the cooling fan and a vibration-damping dual-mass flywheel round off the surprisingly economical turbo refurbishment.

75 years of AMS Porsche 911 Turbo 06 1990

HP Seufert

The technical data from issue 06/1990.

After all, the result is quite impressive. 320 PS (236 kW) mean a specific output of 97 PS per liter of displacement, which secures the Porsche one of the top positions among catalytic converter-cleaned turbo engines. The torque is also remarkable: 450 Nm at 4,500 rpm are offered, 20 Nm more than before, at that time still without a catalytic converter, 20 Nm more than in the five-liter V8 of the Porsche 928 GT. It is not without pride that the turbo developers refer to another effect of the all-round treatment. The new Turbo now also complies with the strict noise regulations in Switzerland, and all without a noise capsule. Even the transmission had to do its part. In order to perform better in the officially prescribed pass-by measurement, the mean gear ratios of the otherwise unchanged five-speed transmission have been slightly modified. There was no space in the turbo for the six-speed gearbox that had already been tried and tested in the Porsche 959.


New tires and new braking system

But it is not the drive improvements that bring the greatest progress with the new turbo. This is undoubtedly due to the new base. The generation change, which rejuvenated the Carrera in body and chassis from the ground up, also benefits the turbo in full. Floor assembly and wheel suspension are basically the same as the Carrera 2. At the front, the axle halves and the articulation points of the struts had to move further outwards to widen the track (from 1,380 to 1,436 mm). New semi-trailing arms at the rear serve the same purpose, enlarging the track from 1,372 to 1,501 mm.

75 years of AMS Porsche 911 Turbo 06 1990

HP Seufert

With the 17 inch wheels, the Turbo is breaking new ground. The advantages are not just visual.

The chassis technicians expect a lot from the new tires. The Turbo is the first production car to roll on 17-inch wheels, lavishly equipped with 205/50 (front) and 255/40 (rear) tires. The new brake system is also turbo-specific: at the front, the discs and brake calipers come from the Porsche 928, at the rear the front brakes from the 944 Turbo were used – a handle in the modular system that hardly increases braking performance compared to the previous model, but reduces costs. ABS is a standard feature, as is a hydraulic brake booster as in the Carrera 4. Finally, the blessing of the general 911 progress is documented by the steering. Front axle geometry and power steering are the same as the Carrera 2, so their beneficial effect on driving characteristics is already well known.

75 years of AMS Porsche 911 Turbo 06 1990

HP Seufert

New streamlined exterior mirror.

Price: 170,000 marks

On the body side, the upgrade compared to the underlying Carrera is limited to an expansion of the standard equipment. An on-board computer, here with a digital boost pressure display, is now just as much a part of it as the air conditioning, which is certainly not an exaggerated luxury in view of the basic price of probably 170,000 marks. On the other hand, the double airbag for driver and front passenger remains subject to a surcharge.

75 years of AMS Porsche 911 Turbo 06 1990

HP Seufert

The digital boost pressure display distinguishes the turbo instruments.

The question that remains is that ultimately everything revolves around the turbo. Is this the fastest production Porsche of the modern era? At least the acceleration values ​​suggest this. For the prestigious discipline from zero to 100 km / h, Porsche mentions a smooth five seconds, which reserves the pole position for the turbo among the German super sprinters. On the autobahn, however, he has to share the leading position. 270 km / h are promised, five less than with the 928 GT, but enough to enjoy the turbo with caution in the future.


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