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Callaway Of the Month Nov/Dec '03

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Reeves Callaway's 1988 Callaway Sledgehammer Corvette

This month, in celebration of the 15th Anniversary of its record top speed run, we feature a very special Callaway Corvette – Reeves Callaway’s “Sledgehammer”. 

Considered to be the ultimate super car, this car was built with a single purpose, to be a 250mph showcase for Callaway’s turbo technology while retaining all of its drivability and the civility of a standard Corvette.

The Sledgehammer project began after the famed “Top Gun” project where a Callaway Corvette was prepared for the Car & Driver Magazine “Gathering of Eagles” test event. In that event, Reeves Callaway drove a Callaway Twin Turbo Corvette to a maximum speed of 231 mph (a production Callaway also ran in that event, with a top speed of 187.95 mph). The Top Gun lived up to its name and walked away the winner but shortly after that test, Reeves Callaway began to put together a list of items he would do differently – items such as, low speed drivability, all power options retained (including air conditioning and radio) and, had to be driven to and from the next event at the Transportation Research Center (TRC).

Starting with Callaway Corvette # 88-051, the crew that Callaway Cars enlisted began to formulate their plans according to Reeves’ ideas. These plans included Engine, Suspension, interior and, body all in a package to demonstrate and make a statement about Callaways capabilities.

From its four bolt “Bowtie Block” to the special pistons and rods inside, to the Brodix heads atop the block, the engine was hand built for maximum power and extreme durability. The goal of the car would have you thinking that the engine was radical. However, remembering Reeves’ goal of civility, the car is docile in traffic, much thanks to the cam, which was kept not that aggressive. The engines packaging was tight, especially with the two large turbos saddling the oil pan. The turbo intercoolers were moved from the normal location (one on either side of the intake manifold) to up to the front, behind the bumper area. The relocation of the intercoolers also mandated a special designed hood to clear all the equipment. The turbos selected were Turbonetics T04b units set at 22psi, with a cockpit adjustable boost control dial. Engine power was rated at (a conservative) 898 horsepower @ 6200 rpm with 772 lb-ft of torque @ 5250 rpm which ultimately brought the vehicle above its 250 mph goal.

It should also be noted, Callaway Cars built the engine that powered the Sledgehammer to its record running pass. To set the record straight, while true that another developed engines for the car, Reeves Callaway himself assured me last summer, it was his engine in the car.

The suspension was tuned by Carroll Smith, using a set of Koni shocks and some other tricks including, relocating the lower control arms for proper control at speed and lowering the car overall by one inch. Special Goodyear tires were also developed and used on the car mounted on the standard 17 inch Dymag Magnesium wheels. Goodyear also sent tire engineer, Reed Kryder to monitor the tires during the record speed run and the tires performed flawlessly.

The interior was kept mostly stock with modifications done primarily for safety. Remembering that this car was to retain its civility, the power windows & locks, Bose radio, electronic A/C and, power sport seats were all retained. Items added were a fire safety system, sumptuous leather covered roll bar with 5-point harnesses and, some additional equipment used for monitoring, was added into the passenger side of the dash.

The exterior was another story though. The Sledgehammer introduced the world to the Callaway Aerobody  package. The first of many collaborations between Deutschman Design and Callaway Cars, the Aerobody was the most exciting bodywork ever supplemented to a Corvette chassis and continues to be one of the most recognized shapes ever to take the road. Designer Paul Deutschman was tasked with providing a design that would remain stable at the 250 mph mark and remain aesthetic to the eye – He succeeded on all accounts and the design ultimately became available on B2K Corvettes beginning in 1989 and remains available today, from Callaway Cars.

On October 19, 1988, the Sledgehammer was driven out of the Callaway shops in Old Lyme, CT, beginning its journey to the Transportation Research Center (TRC) in Ohio.

Once at TRC, after the car made a few laps some issues surfaced – things like a misfire condition at 135 mph and then an oil leak at 199 mph. The elusive misfire was ultimately traced down to a contaminated set of fuel injectors while the oil leak was minor. Keep in mind; these are 200 mph problems, problems that you would never encounter in a standard car, which may have difficulty breaking the 150 mark.

Bad weather was abound throughout the testing session and warm up laps were done in the rain, at 130 mph. As testing continued, it was discovered that the airflow at the nose of the car was flowing out instead of feeding in – maybe the rain and wet weather was helping out after all J Special Callaway “speed tape” was applied and the car returned to the track.

The car was now running at speeds above 200 mph around the TRC 7.5 mile oval track. Just as it seemed the car was headed on the right path, running in the 210 / 215 mph mark, the folks at TRC said, “The car seems to be fine, do you expect a few more miles per hour”? At that point, Chief Engineer Tim Good said, “No, you don’t understand – this car is supposed to go 250 mph”. The TRC Engineer turned and snickered and from that point on Tim said, the whole attitude changed from the TRC staff “it was like having a disease”.

More determined than ever, the Callaway crew headed back out to the track. An “almost full throttle pass” yielded a 248 mph run. It was then, a TRC engineer asked if it would go faster… Tim said “Yes it will” and so the track remained open.

At 3:45pm on October 26, 1988, the Callaway Sledgehammer Corvette was piloted to its record speed of 254.76 mph around the banks of TRC.

The car was driven by John Lingenfelter after Reeves had returned from overseas with the flu. After setting the speed record, the crew celebrated their victory and prepared to head home. Before leaving, John Lingenfelter was quoted as saying “you know, your car goes 100 mph faster than mine” referring to his standard Corvette. J

The 254.76 mph record setting run is just as much of a legend as the day it was set back in 1988. Reeves Callaway and his entire crew have made their mark in automotive history with that machine J The car has been shown at Corvettes @ Carlisle, the National Corvette Museum and recently, at the Petersen Automotive Museum.

Reeves is offering this one of a kind Callaway at the upcoming Barrett-Jackson auction in Scottsdale, Arizona.

Please click on any of the images for a full size version.



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