26 January 2017

Topping 250 requires a Sledgehammer

For most Corvette buyers, the performance and distinctive styling of their cars is perfectly adequate right out of the showroom. For some, however, more will always be better.

That’s where tuners like Callaway Cars step in. One of several outfits in the business of tweaking Corvettes for more horsepower and improved handling, Callaway – like Lingenfelter and Hennessey, two prominent competitors – also alters the bodywork to improve airflow and lend a distinctive look.

Among all the Corvettes cranked out by these wizards over the years, one from Callaway’s four-decade history stands out: the Sledgehammer.

Described by the company’s founder, Reeves Callaway, as a “rolling laboratory,” the 898-horsepower, twin-turbocharged Sledgehammer of 1988 was conceived with a simple engineering goal – to go to any speed event in the world and win. In addition, it had to be street legal, and it had to get to those events under its own power with socially acceptable behavior around town. Raising the bar even higher, Callaway insisted that the car must have all the comforts: air-conditioning, cruise control, sound system and comfortable seats.

While the Sledgehammer was a one-off and never intended for production, it served as a development mule for various mechanical and aerodynamic bits that would later find their way into other Callaway models.

In the 1980s, car magazines were big on annual top speed competitions, pitting high performance models from different manufacturers against one another. The object of the game was simply to discover which car was fastest in a straight line. While dubious as a measure of anything useful, the tests did sell many magazines. They were also dangerous and expensive, pushing engines, tires and other components to the limit while putting drivers at risk. Predictably, speeds rose every year.

“At those speeds, even an encounter with a bird could be fatal," Callaway said. “There are no venues where it’s safe to do it, and there’s no skill involved.” He went on to say that the Bonneville Salt Flats were ruled out by the corrosiveness of the salt and the uneven surface, adding that there just weren’t  suitable locations for extended top-speed runs.

By all counts, the Sledgehammer was a success, achieving 254.76 mph on the high-speed oval at the Transportation Research Center in East Liberty, Ohio. And it drove the 700-miles from the company headquarters in Old Lyme, Conn., carrying Callaway engineers in climate-controlled comfort, enjoying their tunes. Once the run was over, they turned around and drove back home.

According to Callaway, the trip proved the Sledgehammer’s stabilizing aerodynamic aids’ effectiveness and the durability of its twin-turbo engine. And while no more Sledgehammers were ever built, the record-breaking speed generated a lot of publicity and helped sell other twin-turbo Callaway models.

Whether that 255 mph mark had any effect on ending the annual high-speed shootouts is not known. But the fact is, no other street-legal car could touch it at the time.

As impressive as the Sledgehammer’s high speed and long distance debut was, it’s only fair to mention that Callaway Corvettes have had some reliability issues in the past, some even documented during road tests by publications like Car and Driver.

But as Dave Kinney, publisher of the Hagerty Price Guide, points out, to be on the leading edge of development requires a willingness to stick your neck out.

“Cutting-edge engineers like Callaway have helped drive competition that has brought us higher performance cars from the factory, along with increased reliability,” Kinney said. “Somebody has to be out front and take the risk.”

The lone Sledgehammer was offered in a 2014 auction, but the high bid of $600,000 was not good enough to make a sale. It is in the hands of a Colorado collector, far from any high-speed venues. Its record breaking days are over, but its legend lives on.

4 Reader Comments

  • 1
    Walt Boehme St Augustine, FL February 15, 2017 at 17:41
    I remember the Sledgehammer well. They had engine power up to 950 but decided to detune it to help the drivetrain. I believe the first buyer paid less than 150K for it, which should really embarrass the multi-million dollar Veyrons.
  • 2
    george jones northeast February 16, 2017 at 16:28
    Top speed runs were dubious at best?? They still go on today. Limestone Maine, loring afb speed runs and one in Texas i forget where. Silver State run in Nevada. Sometimes your articles come across very pompus and mis informed. JMHO
  • 3
    John Tate Macon, Ga. February 16, 2017 at 08:41
    I had the pleasure of seeing the car at the Corvette Museum in bowling Green Kentucky in late 90's. It is a fine engineered Corvette far ahead of it's time. I had read about in magazines since it was built. It alone was worth the visit.
  • 4
    Michael L Andover Ct. February 19, 2017 at 15:00
    I saw this car on the lift at the Old Lyme location wile leaving of a regular Callaway for Turbo repair. The workings under the car were just as impressive as the visual,WOW

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