1979 Porsche 924 Turbo Drive: Kicking It Up a Notch

Car and Driver

10 hours ago

From the February 1979 issue of Car and Driver.
Understanding the Porsche 924 Tur­bo is easy. Just put your foot into it. Not much will happen for a second or two, but when the tach needle clears three grand, you'll think an afterburner has been touched off.
This is the first 924 in which speed is of the essence, and that's just the boost this car needed. Sports cars are expect­ed to have a more favorable perform­ance-to-dollar ratio than other cars: per­formance should be in direct propor­tion to cost. The standard 924 is a little behind in the equation, but the 924 Turbo is dead-on, offering lots of speed and quickness for lots of dollars—140 mph in European trim for a cool $20,000. Now before the groans and rolling eyes start at the thought of a twenty-grand 924, consider this: the 924 Turbo cost no more than a stripped 911SC. It's almost the 911's equal in a straight line, and it's free of the 911's diabolical tail-happiness, which has am­bushed more than one expert driver and flung them backwards into the weeds. So, as an alternative to the aging but still vital 911, the 924 Turbo actual­ly makes a lot of sense.
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Gero Hoschek
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The extra six grand the Turbo badge costs gets you a 30 percent increase in power. American 924 Turbos, when they debut late next spring, will be par­celed about 150 hp, 35 more horses than are under the hood of a normal 924. We can't vouch for the perform­ances of U.S. cars just now, because the prototypes we drove at Porsche's press preview in Germany were built to Euro­pean specifications. Those cars had a healthy 170 hp (DIN), so were a bit more muscular than the U.S. versions will be. Nevertheless, the same basic modifications will be made to all 924 Turbos, European or American.
The heart of the system is of course the turbocharger, in this case a KKK unit located down low on the engine's right side. It incorporates a pop-off valve that opens when you lift off the throttle. This valve and its attendant passage recirculate exhaust gas through the exhaust-side turbine. This keeps the turbine's speed—and hence its pressur­izing capability—from dropping off when you close the throttle momentari­ly, as you would during a shift. This bit of technology, by the way, was derived directly from the Porsche 917 Can-Am car of Mark Donohue and was seen first on the King Kong 930 Turbo street car. Downstream of the turbo's exhaust tur­bine is a wastegate, the preferred meth­od of boost control, set to allow a hefty ten pounds of boost pressure.
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Surprisingly little else was done to the basic two-liter powerplant to prepare it for the stresses of increased power. The block, crankshaft, connecting rods, and camshaft are unchanged. The head is slightly revised with larger exhaust valves. There are different pistons, and an oil cooler has been added to help dissipate the extra BTUs created by the turbocharger.
But the extra dollars on the Turbo's window sticker get you more than raw horsepower. As you'd expect, knowing Porsche, the chassis has been upgraded commensurate with the increased per­formance potential. To rein in all the extra ponies, four-wheel disc brakes were deemed necessary. To make room for larger discs, Porsche opted for fif­teen-inch wheels rather than the stan­dard car's fourteen-inchers. And while they were at it, Porsche designers whipped up a new spider-web wheel de­sign. The new 15-by-6-inch rims carry 185/70 rubber, for a slightly larger tire footprint than before. The 924 Turbo also gets the five-speed transmission that is standard on all 1979 924s. Final­ly, the Turbo driveline is beefed up in all the necessary places to withstand the greater torque of the blown engine.
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The only visual clues you have that there is an exhaust-driven supercharger under the hood are a minuscule, soft-­rubber rear-deck spoiler, the special wheels, four new slots above the front bumper, and a NACA duct on the hood (put there not to feed the turbo but to help cool the engine compartment). The interior, with its annoyingly low­-placed steering wheel and recalcitrant pedals, is virtually a carry-over from the standard 924.
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Porsche has made a concerted effort to upgrade the overall quality level of the Turbo, however. To that end, there's more sound insulation through­out, and there's been a general tighten­ing of the bits and pieces that in the past have tended to buzz or rattle. The tur­bocharger adds an extra measure of qui­etness since it acts as an additional muf­fler. It all seems to work, because there is now a feeling of quiet refinement as you motor down the road. Final quality judgments, however, will have to wait until we see U.S. production cars.
In other ways too, the 924 Turbo seems to have come of age. Mostly this is a result of the generous power curve balancing the already virtuous agility. In normal driving, when you use the throt­tle sparingly, the 924 Turbo feels, well, just like a 924—though there is an almost subliminal whistle present. But when you hold your throttle foot down, the whistle turn into a whoosh that will be recognized by those who have wit­nessed an accelerating 935 IMSA racing Porsche. There is no subtlety to the 924's turbo; it lets you know it's there with a solid surge of power that pushes you into the seat as the tach sweeps past 3000 rpm. You can feel it fall off boost slightly between shifts, despite the spe­cial plumbing designed to prevent this, but it's back on full song a split second after your boot hits the floor again. In the lower gears, the transition to full boost is sudden. Exiting a second-gear corner, for example, you'll feel the rear tires start to scrabble underneath you as the boost builds. Keep your foot in it and they'll turn to jelly, slewing the tail sideways. Clearly, there is enough pow­er here to keep your attention.
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The well-muscled engine, combined with the 924's good brakes and stable, slightly understeering handling, made our foray through the Stuttgart country­side both exciting and memorable. Out on the autobahn, the 924 Turbo was equally spicy. Set it loose and the scen­ery blurs, pronto. Darkness and heavy traffic prevented us from validating the factory claim for top speed. But that's a moot point anyway, since American cars will have less power and will likely be geared for less top end but equal accel­eration (0 to 60 mph in about 7.8 sec­onds). Still, 110-mph cruising was ef­fortless and reassuringly stable, and bursts to 125 mph were easy work. This 924's got legs.
And that's really the 924 Turbo story. Speed, lots of it, and quickly. No 924 Turbo pilot will ever have to slink away from stoplight competition. In the hands of a good driver, a 924 Turbo will catch and pass just about anything on the back roads. The 924 is finally a truly balanced high-performance car, and no excuses or apologies have to be made to anyone, anywhere.
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But is it worth twenty grand? Well, for that matter, is a 911 worth what it costs, or a bottle of Dom Perignon, or a pair of Gucci shoes? The answer, of course, is yes and no. Porsches have survived because they offer their own exclusive brand of performance, and because the market will bear them. The Porsche 924 Turbo may be a far cry from the cars that looked like bathtubs and sounded like Beetles, but in philos­ophy it's not really all that different from its predecessors: fast, expensive, and exclusive. Proof, you might say, that the more Porsches change, the more they stay the same.
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Specifications
Specifications
1979 Porsche 924 Turbo
Vehicle Type: front-engine, rear-wheel-drive, 2+2-passenger, 2-door hatchback
PRICE
As-Tested: $20,000 (est)
ENGINE
turbocharged inline-4, iron block and aluminum head
Displacement: 121 in3, 1984 cm3
Power: 170 bhp @ 5500 rpm
TRANSMISSION
5-speed manual
DIMENSIONS
Wheelbase: 94.5 in
Length: 170.1 in
Curb Weight (C/D est): 2565 lb
Reviewed by
Rich Ceppos
Director, Buyer's Guide
Rich Ceppos has evaluated automobiles and automotive technology during a career that has encompassed 10 years at General Motors, two stints at Car and Driver totaling 20 years, and thousands of miles logged in racing cars. He was in music school when he realized what he really wanted to do in life and, somehow, it's worked out. In between his two C/D postings he served as executive editor of Automobile Magazine; was an executive vice president at Campbell Marketing & Communications; worked in GM's product-development area; and became publisher of Autoweek. He has raced continuously since college, held SCCA and IMSA pro racing licenses, and has competed in the 24 Hours of Daytona. He currently ministers to a 1999 Miata, and he appreciates that none of his younger colleagues have yet uttered "Okay, Boomer" when he tells one of his stories about the crazy old days at C/D. Read full bio