Chevrolet Corvette L48 Turbo Prototype (C3) – Archived Feature

Back in the old days, the Corvette sliced a broad swath of respect across the land as America’s leading edge of engineering. It was a rolling showcase of all the latest automotive advances, a sports car that GM engineers used to introduce fuel injection, plastic body parts, four-speed transmissions, all-disc brakes, and countless other technological advances, most of which took years to trickle down to family sedans. For the last decade, however, the Corvette’s image has stagnated. If it was ten years ahead of its time after the last major redesign in 1968, today it’s at least two years out of date.

Even though nothing exciting has happened to perk up the Corvette’s prestige in the past twelve years, we’d be the last to predict this car’s glory is gone. At the moment, 50,000 sports cars hardly leave a blip on GM’s annual sales charts. This, along with the fact that dealers still have to fight Corvette buyers off with clubs, is enough to keep the two-seat Chevrolet dead last in priority for re-engineering.

Right now we know the Corvette’s turn for overhaul won’t come before 1984. As we outlined back in December 1978, the new car will approximate a V-8—powered Porsche 924 in concept: front-engine—rear-transaxle in layout, much lighter, somewhat smaller, and as slippery through the air as GM’s wind-tunnel team can make it.

The venerable small-block Chevrolet V-8, now heading into its 26th year of production, will power all Corvettes in the foreseeable future. It will be smaller than today’s 350 cubic inches, for better fuel economy, but steps will be taken to offset the displacement deficit. Which brings us to the subject of this test, a turbocharged, fuel-injected prototype of the Corvette’s future.

On the street it’s a silver bolt of lightning waiting for your foot to say when to strike. There’s enough all-American low-end torque to give you a nosebleed, and the dreaded turbocharger lag has been virtually eliminated at any speed. Yet if you tread lightly on the throttle, this turbo time bomb is absolutely docile and drivable, as mannerly as your average Seville. About the only clue that there’s a short fuse under the hood is a distant, eerie whistling from the turbocharger during certain part-throttle conditions.

Call it a turbo-fuelie, if you’d like. Call it Corvette good times revisited, but don’t rush off to place an order at your dealer just yet. While it was in fact Chevrolet Engineering that cocked this silver bullet and shot it over to tantalize us, you can’t buy anything like it. In truth, there are no plans as yet to produce such a combination. Right now, this Corvette is merely a development tool for Chevrolet’s Product Promotion Engineering Department, and like many turbocharged hot rods of the past, it’s strictly experimental.

Even so, you can tell it’s a serious effort because the design is so production-like. Detroit is old friends with AiResearch by now, so this West Coast firm is the source of the turbocharger. The fuel-injection system is almost exactly like Cadillac’s California Seville equipment, although special modifications have been made by Bendix in the computer controller to suit turbocharging. There’s an Edelbrock intake manifold to feed the engine its pressurized charge—one component that was chosen out of convenience. Since Edelbrock has its own aftermarket fuel-injection system for the Chevrolet small-block (using Bendix-made injectors), its aluminum intake manifold offered a handy bolt-on for this application.

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