Based on units from the racing division, the
Porsche 959 was an exceptional performer, and as only 200 were built, these cars are true collectors’ items. Despite a fairly small engine of less than 3 liters capacity, the 959 had a top speed of 198 mph, and took just 3.6 seconds to get to 60 mph – and this was in 1987! It is amazing how many supercars with much bigger engines still can’t match those figures.
Based on 911 but very different
To simplify manufacture, Porsche based the car on the structure of the 911, which was modified extensively both mechanically and to reduce weight. The engine was a special 2.9 liter unit, turbocharged to a high boost level to whack power up to 450 bhp. To get this power onto the road, Porsche adopted full-time four-wheel drive for the first time.
Unfortunately, the rear-engined layout of the 911 was retained, so the car was tail heavy, which made it difficult to handle. This is a feature of all 911s, although the later ones have been modified in many ways to improve handling.
Since only 200 were built they could have modified the body to convert it to a mid-engined layout, but that would not have been good for the image of the 911, which is resembled closely, and the rear engined layoutr was retained.
Water-cooled heads, air-cooled cylinders
At the time, Porsche’s road-going engines were still air-cooled, but some of the racing engines had water-cooled cylinder heads and air-cooled cylinder barrels. This was the layout adopted for the 959; it was the only way of getting enough coolant to cope with the massive power output.
The engine was a typical Porsche flat-six, with chain drive to the twin overhead camshafts on each bank. There were four valves per cylinder. This was a very oversquare unit, with a bore of 95 mm and a stroke of only 67 mm. The maximum power of 450 bhp was produced at 6,500 rpm, with 370 lb ft (500 Nm) torque at 5,500 rpm. This was a massive amount of torque for such a small engine, while the specific output of over 150 bhp per liter was also very high for that period. It went like stink!
Two-stage turbocharging
To get this much power, Porsche used an innovative turbocharging system, which we will hear more about in the next few years, almost 20 years later! There were two turbochargers, and instead of each supplying three cylinders all the time, one operated at low speeds, and both at high speeds –two-stage turbocharging. This system produced strong boost at low and high speeds.
At up to 4,300 rpm, one turbo operates, and then the second comes in as well, owing to rather complex manifolding. Maximum boost is 2.0 bar, which is typical of racing engines, and the boost pressure was controlled by a wastegate.
The drive was taken through a massive six-speed gearbox to the transfer box, so drive could be transmitted to all four wheels. Large oil coolers were needed to keep the engine and transmission cool; these are mounted at the front.
Wishbone suspension
Porsche leaned heavily on its racing experience for the suspension, adopting double wishbones front and rear, instead of the struts of the 911. Wishbones give better camber control and also a more stable roll axis.
Unusually, though, there were twin spring/damper units at each wheel. One damper each side regulated the ride height, which was adjustable between three heights. The other dampers were also adjustable – they adjusted the hardness of the damper settings. This suspension was well ahead of its time.
To get the power onto the road, and keep the car on the road, wide tires and big drilled discs were used. The tires were 235/45VR17 at the front, and 255/45VR17 at the rear – these days, the rear tires would be wider to cope with that power and balance the handling.
Wide body, lightweight panels
To reduce weight, and provide room for the wide wheels, the body was modified, and is wider and longer than the standard car. Kevlar/carbon fiber composites were used for most of the new panels, and aluminum for others. The tail was extended, and carries a large fixed spoiler, and the rear end lifts up to give much better engine access than is normal on a Porsche. There were big air outlets low down in the tail.
For a car based on a standard steel body, and one with four-wheel drive, the 959 was pretty light at 3,199 lbs (1,452 kg). Despite the problems of that excessive weight at the rear, the car was a great performer, if tricky to handle. It remains a classic car that broke the mold.
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