Two different close-ratio 4-speeds are available on the Corvette, the normal one which Duntov says is plenty good enough for any kind of street use, and the M22, known as the “rock crusher” to those who can’t remember M22. The difference between the two is the gears — a little straighter cut on the teeth in the rock crusher — and a great deal of noise. Both of the boxes shift alike because the synchronizers are the same. And they shift very well because of the Corvette’s excellent shift linkage. Unlike other Detroit 4-speeds, the Corvette linkage is mounted to the frame — which means that it doesn’t have to be rubber-isolated to avoid rattles and vibrations. So you get solid shifts but no lever buzz. The shifter is also adjustable for a shorter throw.
They may have in the braking department, however. Corvettes have extremely powerful brakes and three of the four test cars easily lived up to expectation. But the fourth — the nose heavy, air-conditioned, all iron 454 — preferred to lock up its rear wheels early and could pull only a little over 0.8G and still maintain good directional stability. No brake system proportioning valves are used in the Corvette and although there is a considerable weight distribution variation between models, Duntov is convinced that none is necessary — but he planned to recheck the nose heavy car situation on his return to Detroit just to make sure.
When it comes to handling, the variables are even more complex. According to Duntov, production cars can range all the way from 0.75 to 0.85G on the skid pad. The 454s are usually better because those models have a rear anti-sway bar which makes them almost neutral. But you can’t count on it. There is a considerable variation in suspension rates: up to 10% in the springs and nearly as much in the anti-sway bars — they can’t be produced to tolerances closer than that at a reasonable cost. And then there are the tires. For all considerations that make a good street tire — directional stability, ride quality, noise, etc. — the Goodyears are slightly better but the Firestones will usually generate a fraction more lateral force on the skid pad. Then there is car weight, which varied in this test from 3370 to 3675 lbs., and weight distribution. In this test the lightest car, the LT1, turned out to be best, circulating around the pad at 0.80G. It also had the least understeer.
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But on the road course it was almost impossible to feel the difference between the four versions. All of them understeer slightly — just the right amount in our opinion — and are extremely tolerant of driver technique. For those who intend to race there is an optional heavy duty suspension but it is so hard that Duntov doesn’t think anybody could stand it on the street. And to discourage the masochists, he has fixed it so that you have to special order a heavy duty car — intended strictly for racing, with heavy duty brakes, clutch, rear end, etc. — and not a single convenience option, not even a radio, is available on that model.
It’s all a part of Duntov’s loyalty to Corvette drivers. He wants them to have what they need — as opposed to what they think they need — in an extremely high performance road car. Because of that desire he frequently finds himself at odds with the stylists. The deluxe wheel cover option is a case in point. The Turbo-Flash styling adds 28 lbs. to the car and makes it impossible to dynamically balance the wheels. Duntov recommends the base hub-cap-and-trim-ring setup. And there have been even more serious conflicts over the basic body shape. Originally the stylists had a big spoiler slated for the rear of the current Corvette before it went into production. Duntov insisted that it be trimmed down to its current non-functional size. Testing had shown the spoiler pushed the rear down so hard that the nose came up, causing the front end to go light — far worse than no spoiler at all.
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Occasionally you find a problem that hasn’t been fixed. On the 140-mph pass through Nevada in the LS5 we discovered that it would only run wide-open throttle for a few miles before it would overheat. When the subject came up later Duntov nodded — he knew it. It’s because of the radiator shroud. You have to have it at low speeds so the fan will be effective but at high speeds it sort of corks off the flow of air that would otherwise be rammed through the radiator. He has the solution on the shelf — a shroud with flaps that open at speed — but the bean counters aren’t too interested in that. And since it’s not a safety consideration, there is no reason to press the issue. Duntov knows about discretion. It comes with age.
Which is a subject he doesn’t talk about much. He’s close on sixty and it is weighing on him. But it doesn’t stop him. Seemingly, nothing can. You see it when he drives. A few laps at the photographer’s insistence — just to finish off. Never mind that it’s just to use a roll of Tri-X. It’s done right. Wide open throttle till the last millisecond — brake late — brake hard — on the power early. Not a twitch in the line. Just a taste of tire smoke filters through the cockpit. Hell. Zora Arkus-Duntov will still blow the doors off 98% of the guys that buy his cars. And that bodes well for next year’s Corvette.
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