Curbside Classic: 1991 Porsche Carrera 4 – Messing With Perfection

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(first posted 3/28/2014)     Coming across cars like this Porsche is a real treat.  It’s gorgeous, instantly recognized and well liked.  Most of the time, these are kept in garages and only taken out when their owners want to give them a proper workout, in which case, they won’t be sitting still long enough to take a good photo.  An under-recognized quality of 911s, however, is their ability to serve as daily transport, uncommon among true sports cars.

For comparison, consider the FD RX-7 parked near my house that I’m dying to snap pictures of and write about. It’s spent the last several months under wraps in a carport, and therefore cannot currently qualify as a Curbside Classic.  Without that car’s lightly-laden rear end and fragile twin turbo rotary, this more exotic Carrera 4 actually works better for our purposes, its versatile and stout nature making it a very practical choice for everyday use, as we see here.

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The 964, introduced in 1989, left an indelible impression on me as a young kid.  They shared showroom space with that other four-wheeled repudiation of physics, the Audi line-up, and because my dad’s ’84 5000 was always in the shop for one thing or another, I saw them regularly.  There was always a red 964 lurking in the background as my dad slid yet another check over to the service adviser who was more than happy for the business during those lean years, as if to underscore the steep prices he was continually forced to pay to repair his Typ44.  Because I’d seen countless 911s in movies, these expensive trips were a much more positive experience for me, and I actually encountered the modernized second generation car before ever seeing any classic 911s in the flesh.

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Much as all wheel drive helped negate the effects of the Audi’s old fashioned longitudinal front-drive layout, its appearance on the 964 was meant to mitigate the Porsche’s extreme rear bias.  A complex system, PDAS (Porsche Dynamische Allrad Steuerung) helped channel some of the extra power away from the rear wheels, but as there was little weight over the front axle and because weight shifts rearward under acceleration, the benefit was questionable.  More likely, Porsche was trying to capitalize on the 959’s reputation by introducing the new 911 in AWD form only, but wisely introduced the Carrera 2 for 1990, driven by the rear wheels as the gods intended.

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The Carrera 4 used a central high-pressure central hydraulic system, similar in theory, if not in concept, to the Audis it often shared showroom space with.  In the Porsche, it was used operate the brakes and the AWD system, which was controlled by a series of hydraulic clutch packs (the Audi’s system powered the brakes and power steering).  Because it always sent about a third of the engine’s torque to the front wheels, it’s said to have fundamentally altered the 911’s characteristically tail-happy handing and indeed, the 964 is known for understeer, especially at low speeds.  It wasn’t especially lightweight, either, adding about 200 pounds in weight to the car.  When the 993 came out in 1995, the system was replaced by viscous coupling center and rear differentials, which were not only lighter, but defaulted to a 10/90 front to rear torque split, solving both the weight problem and complaints of excessive understeer.

964-c2tip-c4man-copyright-porscheCarrera 2 Tiptronic and Carrera 4

Further changes made to the chassis included the swapping of torsion bars front and rear for coil springs.  It’s said this was done to accommodate the AWD system’s half shafts at the front and a bigger transmission at the rear.  It the front, the A-arm no longer had to carry the torsion bar and was reconfigured.  Besides allowing better fine-tuning of geometry, it enabled Porsche to engineer in a small degree of fore/aft compliance, helping take the jolt out of pavement imperfections.  At the rear, variations in the (now aluminum) semi-trailing arm’s bushing compliance induced stabilizing toe-in under lateral force.  The switch to coils all around also helped the ride by allowing a progressive spring rate that torsion bars cannot provide.

964-4wd-copyright-porsche-downloaded-from-stuttcars-comCarrera 4 drivetrain

Power steering and ABS were standard, for the first time, adding another dimension to the car’s newly forgiving attitude, but again, with such a light front end, the former was arguably an undesirable addition to the rear-drive Carrera 2, which also debuted the Tiptronic automatic transmission, a then widely-publicized piece of kit of questionable benefit.  While useful for holding a lower gear for a prolonged period or for upshifting when the transmission wouldn’t ordinarily do so on its own, most manually controlled automatics still use a torque converter and have very slow response time, offering virtually none of the advantages a manual transmission.  What really mattered, however, was whether or not this four-speed unit could win buyers over from Mercedes, especially since the 928 increasingly failed to do so by this time.

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What didn’t change, for the most part, was the cockpit, with its delicate pillars and close, shallow dashboard.  As we at CC like to remind people, all cars should offer visibility like this.  A new, computer controlled HVAC control and airbag were necessary changes, and as today, Porsche offered all sorts of leather wrapped bits (sunvisors, door pulls, center console, etc.) for a couple hundred bucks a pop, each sold separately.

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Determining the exact model year for this car is difficult.  Its elephant ear mirrors mean it can’t be a ’92 or ’93, though these five spoke wheels, which could’ve been swapped, weren’t used on this car until after 1991.  The manual control for the spoiler on the console–the knob on the left, ahead of the gear lever–mean it’s not a 1989, when it could only be raised and lowered automatically. So this car is a ’90 or ’91.


Last, and certainly not least, was the 964’s new engine.  Designed (finally) to meet US emissions from the get-go, the M64 was equipped with large catalysts and twin spark plugs per cylinder which, combined with retarded ignition timing, allowed a very high 11.3:1 compression ratio.  That’s a heady number for a street car even today, with direct injection commonplace, and was an eye-popping figure for the late ’80s. For US market cars, it generated 247 horses at 6100 rpm and 228 ft lbs of torque at 4800 rpm, so it was not necessarily a screamer.  The quarter mile was achieved in the high thirteen second range at about 100 mph, with sixty usually reached in less than six seconds.

At 3.6 liters with a gigantic 100mm bore, early engines built without head gaskets have been known to leak.  Additional problem included failure of early versions of the dual-mass flywheel, added in 1990, and breakage of the tiny belt which maintained the twin distributors’ timing.  The 964’s name has been somewhat tarnished by these problems, but they don’t fully account for the car’s lagging reputation compared to other air-cooled 911s.


Rather, the 964 has long suffered from an image problem.  On one hand, it lacked the gravitas of the previous model, and on the other, the 993 which succeeded it in 1994 was not only regarded as better most every way, but also wasn’t “guilty” of displacing the original car, a bona fide classic, from the lineup.  The 964 was therefore neither fish nor fowl and this was also reflected in its styling.  While the Cd was reduced from .42 to .32, with very favorable lift characteristics, thanks in part to a flat belly pan and other details, the new bumpers looked somewhat tacked on to some who, in all fairness, were quite possibly too attached to the appearance of the old car.

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Only after a decade of solid sales as a luxury conveyance, regardless of its more recent buyers’ knowledge of cars or appreciation for Porsche’s philosophy, was the original 911 truly reconceived to meet the needs of its audience.  One of the ironies of the new 964, designed specifically with this demographic in mind, was that it was met with an indifferent reception and often criticized for being too soft.  Suddenly, it was no longer the “it” car.


It’s also said the 964’s problem was compounded by a world-wide recession, which limited the field of buyers to those with actual wealth, not theoretical financial assets.  If this latest recession is anything to go by, however, the latter point is difficult to comprehend.  These days, it would appear that the affluent are doing quite well and that luxury goods are enjoying brisk sales.


Despite what some may say, the 964 is very, very far from being an undesirable machine.  In fact, its reputation keeps the 964 rather affordable for enthusiasts today.  With a fully galvanized body and, often, a quick-reacting all-wheel-drive system, a car like this can provide low-stress, year-round thrills for about $25,000.  Watch for prices to rise, however, once 993s become unjustifiably expensive.


What’s most important to remember is the change in buyer attitudes since the 964 came out.  In 1989, it received a lot of flak for being too soft around the edges, whereas more recently, we are more acquiescent when it comes to model bloat and softened character in our new cars (the electronics-laden C7 Corvette and latest 911 are good examples).  Sometimes, we even make excuses for manufacturers, reminding critical personalities that such compromises are needed for convenience’s sake or to increase sales.  Considered against today’s sensibilities, then, could the 964 really be that dumbed down?

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