They get no respect, this American-made sports cars. Especially in Europe where performance, handling and exclusivity—not catchy ad slogans—determine the true measure of a car's worth. Sure, the Swiss buy Detroit-built sedans and wagons but one suspects it's an affectation—like wearing denims with your Giorgio Armani jacket. Truth is, most European automotive enthusiasts have little regard for almost any automobile America has produced in recent memory.
But with the introduction o f the Corvette ZR-1—at the 1989 Geneva auto show, of all places—that attitude is about to change.
You may know the ZR-1 as the King of the Hill, which is what this Super Vette was commonly called when the program was barely more than a rumor. For reasons known only to GM brass, that name is now taboo. Our guess is that Chevy, who's seeking international recognition, found the name too domestic, not to mention too long for a car badge—and untranslatable (Le roi de la monlagne? Non. Der Konig am Hiigel? Nein). Better to keep it simple, short and sweet. And alphanumeric so as to capitalize on its similarity to other European exotics such as the BMW M1 and Ferrari F40.
Exotic? Dave McLellan, Corvette chief engineer since 1975, prefers you not call it that. As McLellan sees it, exotics are outrageously styled, astronomically expensive, highly temperamental, limited-production automobiles that are often racers masquerading as road cars.
Sure they're fast (180 mph is median speed for most Bahnburners), but if you were going cross-continent, you would take the Merc or the Bimmer. Until now. You see, the ZR-1, one of the fastest sports cars in the world, is also blessed with superior handling and braking. Yet it is the most civilized and technologically advanced and the least expensive supercar in production because it is still a Corvette.
The ZR-1 looks like a Corvette. There's that unmistakable shape but with a notable difference: The bodywork widens beginning at the leading edge of the doors and culminates in a tail that is 3 in. broader than the normal Vette's—to accommodate the hefty P315/35ZR-17 Goodyear Eagle Gatorbacks made specifically for this car. The soft, polyurethane end cap is different too, convex rather than concave with square versus round tail lights and a small red ZR-1 badge that graces the lower right corner. Chevy studio chief John Cafaro describes the Vette's physique as "muscular," and this is especially evident in the ZR-1, which shares the same front end (front wheels and tires too) with the conventional Corvette, the so-called L98. Another notable difference between the L98 and ZR-1 is weight. Heftier engine, bodywork, tires, etc. make the Super Vette some 200 lb. heavier than an L98 coupe.
As a Corvette, the ZR-1 also shares the Bosch ABS II anti-lock braking, hybridized Z51 suspension and FX3 Selective Ride Control packages with the L98. Ditto the UJ6 Low-Tire-Pressure Warning System, which along with the above is standard on the Chevy flagship. Although the Bosch ABS and the suspension need no explaining (it's basically the Z51 setup with softer springs and anti-roll bars) and the UJ6 is self-explanatory (a light on the center console tells you if a tire is going flat), FX3 does call for a brief description.
Basically, this Bilstein-engineered system, which borrows from Porsche 959 and Lotus Formula 1 technology, uses a gas-over-oil shock absorber whose hollow center shaft is fitted with an adjustable orifice that allows varying amounts of shock oil to be bled off from around the piston. This provides six levels of damping in each of the three modes. Touring, Sport and Performance, for a total of 14 steps (not 18, because some overlap). Settings range from very soft to full hard in incremental steps that are governed by vehicle speed. Lest you wonder how the system works, let's just say that it's done with servomotors (actuators mounted atop each shock and used to turn the shaft that regulates the oil bypass) and a microprocessor (to sense road condition and speed and to send appropriate information to the servos). True, other high-volume manufacturers have offered cockpit-adjustable shocks, but this is the first use in hyper-performance territory. More about this later when we discuss driving the ZR-1.
Unique to the ZR-1 (and for most of us, its raison d'etre), the LT5 engine is a lovely example of double-overhead-cam, 4-valve-per-cylinder technology. Developed jointly with Lotus and built by Mercury Marine (the boat motor people), this 5.7-liter aluminum, 32-valve V-8 has the same 4.40-in. bore center spacing (for standardization purposes) as the venerable Chevy small block. To maintain this distance, the bore has been reduced from 4.00 to 3.90 in., while the stroke has been increased from 3.48 to 3.66 in. Aluminum cylinder liners that are lighter than steel are Nikasil-coated, and the externally ribbed block has a cast aluminum oil sump and lower crankcase assembly whose integral 4- and 6-bolt cast-iron main bearing caps secure the forged steel crankshaft. Up top, the LT5's four camshafts are driven by a roller chain (Gilmer belts were considered, but discarded because they would have made the engine too wide to be bottom-loaded into the Corvette chassis on the Bowling Green assembly line) and actuate hydraulic lifters that eliminate valve lash adjustment. The 4-valve combustion chambers feature centrally located spark plugs (for reduced flame travel) and are designed to act in concert with dished aluminum pistons with an 11.0:1 compression ratio. To ensure that all of this very elaborate (and expensive) machinery doesn't self-destruct for lack of proper lubrication, the engine oiling system holds 12 quarts, seven more than the pushrod V-8.
Nothing unusual so far, you say. Any engine worth its salt has all this. Too right. But no other engine in the world has the LT5's two phase induction system that makes the Chevy 32-valver two powerplants in one: a tractable, fuel-efficient. around-town workhorse; and a gut-wrenching, full-on track star that hammers out 380 bhp. With its 16 tuned-length intake runners, the visually distinctive manifold uses a 3-valve throttle body with a small primary for responsive low-speed operation and two large secondaries for full-power usage. During normal use only, the primary intake ports and fuel injectors are operative. Mash on the gas and let the revs climb above 3500 rpm or to half-throttle, and the secondary ports and injectors come into play. Acting under orders from the Electronic Control Module, the secondaries feed the fuel-air mixture to the larger of the two intake valves whose camshaft lobes have more radical timing for maximum power. In addition to making the LT5 the most versatile engine in the world, the two-stage induction system enables the Vette owner to regulate engine operation. A power switch on the console (the so-called valet-parking key) disables the secondary throttles and their injectors, leaving the engine operating at half power—to discourage unauthorized drivers from using the LT5's full potential.
The ZR-1's V-8 uses direct-fire ignition: Four coils ignite two spark plugs simultaneously, upon receiving their cue from a crankshaft sensor acting in concert with the ECM. Because the sensor reads the position of machined notches on the crank, correct ignition timing is ensured. Spark advance and retardation are electronically controlled by the ECM, which gets an additional bit o f information from a knock sensor. Whether idling or at speed, the 32-valver runs no hotter (and generally cooler) than the L98, thanks to its distinctive cooling system with 15-percent larger radiator and relocated thermostat (it's on the inlet side of the engine).
To help deliver the LT5's output to the rear wheels, Chevy has given the ZR-1 and the normal Corvette a unique 6-speed transmission, which uses CAGS (Computer Aided Gear Selection) that automatically short-shifts from 1st to 4th under light throttle. This beefy, ZF designed gearbox (code-named ML9) replaces the Doug Nash 4+3 manual overdrive tranny used from 1984 through 1988 and is capable of handling at least 425 lb.-ft. of torque, much more than the LT5's respectable 370 lb.-ft. When used with the 32-valver, the 6-speed drives the rear wheels through a 3.54:1 ring and pinion that gives a slightly lower final drive ratio than the L98's 3.33:1.
Of course, the expected Corvette niceties abound (except for the see-through, hard-coated acrylic roof panel, the ZR-1 is what the trade calls "fully optioned out"). This means that, in addition to everything mentioned above, leather-covered sport seats and that great-sounding Delco/Bose system are standard. Paint schemes are standard Corvette and include seven hues, but not the yellow seen on the Geneva show car. Interestingly, there is no climate control, just plain old air conditioning and heating, because at this time the fully automatic system won't clear the right cylinder head.
Considering the car's limited availability (Chevy plans to build only 4000 per year beginning this summer), most early ZR-ls will probably become collector cars, bought at inflated prices and traded at even higher ones. A pity, because if ever there was a car that begged to be driven, and driven hard, this is it. Unlike some exotics that fuss in traffic and fume in hot weather, the LT5 powerplant runs like any good Detroit V-8 should: effortlessly, reliably. In city driving (or while following that ubiquitous diesel truck along a hilly European two lane), this muscular V-8, which develops 300 lb.-ft. of torque at 1500 rpm, burbles along happily at practically idle speed. So there's no need to do a lot of shifting—or to let your blood pressure soar because you're playing follow the leader. Don't worry, be happy, enjoy the air-conditioned stereo-filled environment of your ZR-1 and wait until it's safe to...PASS!
Let the record show that after easing off the line at about 1500 rpm to avoid wheelspin, the ZR-1 goes from 0 to 60 in 4.9 seconds and gets to the quarter-mile marker in 13.4 sec. Speedshifted, Corvette engineer Jim Ingles style, it's a few tenths quicker. When it's time to stop, this 3680-lb. sports car comes to a halt in 132 ft. from 60 mph and 233 ft. from 80 mph. Impressive? You bet! Also, better than the top three exotic cars (Ferrari Testarossa, Lamborghini Countach, Porsche Turbo).
In real-world terms, this level of performance means that, depending on the amount of room you have to do so, you can-either ease into the throttle, activate those giant secondaries and sort of swoop past. Or you can downshift a gear or two (because of the 32-valver's 7000-rpm redline. there's plenty more revs than in the normal V-8) and blow by that slowpoke con brio! And don't fret about ducking back into your proper lane. Those giant, vented disc brakes and Bosch ABS will stop you quickly and safely, even if it's wet or if the road surface is gravely. Or just in time to slow for that DANGEROUS CURVE.
Not a problem. Lateral acceleration (you can just call it handling) has always been the Vette's forte, but this model sets new standards. Ladies and gentlemen, the new king of the skidpad, the ZR-1. Thanks to its suspension, Selective Ride Control and those sticky ZR-rated (193-mph) Goodyear Gatorbacks, the ZR-1 toes the (curved) mark at 0.94g, better than any production-built automobile, bar none. There's mild understeer and a feeling of comparative nimbleness brought on by steering that no longer feels overboosted and darty (the ratio has been slowed from 13.1:1 to 15.0:1). Nor is the Super Vette a slouch in the slalom where it slithers through the cones at 65.7 mph. It's the second-fastest speed we've ever recorded, topped only by the Mitsubishi Galant, a car with front drive (which the slalom tends to favor) and with a highly sophisticated reactive suspension of its own.
The ZR-1 is a real confidence-builder for a driver who suddenly discovers that a certain constant radius turn, isn't. At times like this it keeps all four feet (or tires) planted firmly on the pavement and maintains its composure—with a deft Hick of the wheel or tap of the throttle, if need be.
Much of the credit for this improvement in vehicle attitude and ride goes to the Corvette's Selective Ride Control package. Unlike the suspensions of yore (standard equipment on the 1989 normal Corvette) that provided either soft ride or good handling. FX3-equipped L98 and ZR-1 Vettes offer both—in varying degrees depending on switch setting.
On bumpy roads such as some of the French goat paths encountered during the ZR-l's European press introduction, the Touring mode works best. This soft setting not only keeps one's fillings intact, but also makes the suspension more compliant (better able to absorb much of the road's roughness) and enables the wheels to stay in with the pavement.
On smooth, fast roads or on a test track such as Goodyear's Mireval proving grounds near Narbonne, France, the Sport or Performance modes are best. Here, the flat surface ensures that the ZR-1's Gatorbacks are in constant with the pavement, so the function of shock-absorber damping becomes one of chassis tuning. Suffice to say that the middle (Sport) setting is probably best (even Corvette Challenge competitors use it), while the full-hard setting makes the suspension very responsive to steering input, and (ahem) quite stiff.
From the outset, the Corvette group sought to make the ZR-1 one of the fastest production-built cars in the world. And so it is, even if those Countach curmudgeons and testy Testarossers quickly point out that its 172-mph top speed falls a few digits short of the Lambo's flat-out 179 mph and the Ferrari's 185-mph figure. Perhaps, they should bear in mind that the ZR-1 was tested in California's high desert with minimal approach room, while the exotics were tested in Europe at Volkswagen's Ehra-Lessien test track where we think, given miles to unwind, the LT5 could manage high 170s. Consider also that the Ferrari and Lamborghini are specially built automobiles costing almost three times as much as the ZR-1. which is built on the same assembly line as the normal Vette, and costs $50,000, a bargain considering the level of performance and comfort it delivers.
But is it, as Chevy hopes, a world-class car? (The envelope, please!)
Yes. The Corvette ZR-1 acquits itself well amidst some very fast company. Yet it does so with a level of sophistication and comfort beyond what most exotics (but not specialty cars such as the Porsche 959) currently deliver. Throw in availability and serviceability (the GM-CAMS computer diagnostic system, mandatory service equipment for all ZR-1 dealers) and you have a car that offers the best of the old and the new world.