Porsche 928S-4 — Zuffenhausen’s new flagship
“The Turbo” has, for the past decade, been Porsche’s flagship model, the ultimate 911 that reached supercar status. It lives on, with further development in the pipeline we guess, but the laurels for the most powerful, and quickest, model in Porsche’s production range pass now to the new 928S-4.
At 320 bhp, with or without catalytic equipment, and able to run on 95 octane fuel, the four-valve-per-cylinder V8 engine is the last word in technology. It has been taken out to the full 5-litre capacity that was designed-in from the start (but the energy conscious world was too nervous to accept it) and is capable of propelling the 928 at 168 mph or more in rock-steady fashion.
On a near empty autobahn in the Black Forest we took the 928S-4 up to 260 kmh indicated, almost certainly 160 mph with more to come, but for a motorist far ahead whose safety and comfort had to be allowed for. And, say Porsche’s engineers, the engine was releasing far less pollution into the atmosphere than the 1.2 litre Opel that we were approaching.
At the heart of the development is the new four-valve cylinder head, shared with the 944S model also described this month. Combustion still takes place in the piston crown bowls, which now have oil jet injection (like the 911) to reduce temperatures, but the latest cylinder heads also have combustion chambers recessed by 3 mm to achieve two squish zones in order to increase turbulence of the fuel/air mixture.
A new intake manifold, in magnesium, has been developed in the light of racing experience achieving two-stage resonance charging. The variable system consists of two resonance chambers each connected by a long and a short pipe, the shorter one containing a vacuum operated flap. The resonances peak at 3,000 rpm and 4,000 rpm, boosting the torque curve, and ensure maximum filling of the combustion chambers right through the range.
Another advanced feature is the adoption of two linked systems for injection and ignition, since Bosch doesn’t have a Motronic suitable for the V8. The injection system utilises the hot-wire air flow sensor, while the ignition system has a knock control sensor which will retard ignition at any cylinder under stress; this feature is also seen on the 944 engine.
Even the Porsche people tend not to agree about the “S-4” designation. Engineers think of it as “4-valve”, naturally, while the marketing men refer to it as the “fourth evolution” 928 engine. The first, launched in 1977, was the 4,474 cc engine developing 240 bhp at 5,250 rpm, and 280 lb-ft of torque at 3,600 rpm. Two years later the 928S was introduced with its 4,664 cc engine producing 300 bhp, and 283 lb-ft of torque at 4,500 rpm (and in 1983 the power was raised again, to 310 bhp, with higher compression and Bosch LH Jetronic fuel injection).
The Series 3, however, was introduced in 1985 only for the US and Japanese markets, with four-valve cylinder heads — not those on the latest model, however — and developing 288 bhp with full catalytic equipment, including a Lambda probe. The S4 follows Porsche’s current policy of offering the same power, and same performance, in all world markets, and is capable of travelling three times as fast as America’s blanket 55 mph speed limit.
For all markets the 928-S4 produces 320 bhp at 6,000 rpm, and 317 lb-ft of torque at 3,000 rpm. For the record, the stroke has been increased again, to 78.9 mm, the bore remaining at 100 mm as in the 944 models, and at 4.957 cc the 928 engine is now, literally, a double version of the 944S. It will accelerate to 60 mph from standstill in 5.8 seconds, or 6.1 seconds in automatic form.
For Europe the automatic’s gear ratios have been shortened by 8%, to enhance acceleration, so that maximum speed (rather academic, outside Germany) coincides with peak power at 6,000 rpm. The manual version, using Porsche’s own gearbox, is chosen by around 30% of customers worldwide, and they’ll be pleased to know that the twin-plate clutch, which is good in theory but has a life of only 20,000 miles upwards, has been replaced by a single-plate clutch of 10-inch diameter, with the promise of longer life for the linings.
New front and rear bumper coverings, still in polyurethane, offer lower air resistance, and an under-tray beneath the engine, and a larger real wing (hinged to lift upwards, to facilitate window cleaning), combine to reduce the Cd figure to 0.34. Also assisting here is a “venetian blind” cowl ahead of the radiator, coupled with twin electric cooling fans instead of a single viscous blade.
The 928S-4 becomes Porsche’s only V8 model, which will be produced at Zuffenhausen at a rate of 22 per day, a sure sign of the health of economies in the major markets. The price has been raised by 20% to DM 119,500, and Porsche Cars Great Britain still has customers on a waiting list for the allocation of 300 cars annually, each one gift-wrapped at £46,534. Only four years ago the “basic” 928 4.5 cost a mere £21,000, but there’s no lack of enthusiasm out there for the technological marvels offered today.—M.L.C.
This year Porsche has introduced so many new model variants, one almost expects the company to announce ‘this month’s new car’. The latest is a four valve per cylinder addition to the 944 range, the 944S. Of the 1,300 normally aspirated Porsche 944s to be imported next year, 800 are expected to be the new model so, in the company’s terms it is a significant addition.
The 2.5 litre engine delivers 190 bhp at 6,000 rpm, whether or not it’s fitted with a catalytic converter, with maximum torque of 169.6 lb-ft at 4,300 rpm.
So much for the basic details: the problem with this car is its price. Even allowing for the current state of the pound sterling against the deutschmark, the basic £23,997 appears pretty steep, for the 944S is not at all special.
Its badge, and clever marketing, will undoubtedly mean that Porsche will achieve its sales target and the cars will continue their tradition of maintaining their secondhand value, but one wonders how long this can be maintained. To ask £73.51p extra for a cassette and coin holder, speaks of a certain cynicism unless it is gold-plated. One wonders, too. how Porsche can justify £915.69p for a removable sunroof panel with electric tilt.
Styling is a matter of taste, but I find it mediocre. The gearbox is fine, but it’s not better than’s to be found on many cars at a third of the price. The steering is good, but is not exceptionally good. ABS, which is standard on the 944 Turbo, is not even offered as an option on this model and the brakes on the car I drove recently were so spongey that I stopped to investigate them after a few hundred yards.
Possibly one is looking for extraordinary performance and a claimed top speed of 142 mph is impressive, but few of us stray into that area on British roads unless we want to lose our licences. The claimed 0-62 mph time of 7.9 seconds is respectable, but there are currently ‘hot hatches’ which will beat it.
One cannot even say that the car’s overall feel is exceptional. There’s nothing wrong with it, it’s taul and competent, it has a pleasant ride, noises levels are low (save for the boom from the rear suspension when going over bumps) but at the price one expects something extraordinary. — M L