The '88 B2K cars provide another example of how detailed engineering was required in order to meet Callaway's performance expectations. Starting with the '88 model year, all Corvettes used a new crossmember. The improvement to chassis torsional value was so significant that GM engineers took to calling it the "Wonder Bar."
Unfortunately for Callaway, the new bar was in the way of the air-intake system. The company's solution was to cut the crossmember out of the car, hollow it out, flange the ends, and add brackets to it. Callaway then bolted it back into the car, where it served as an air duct. Although complex and time consuming, this modification added almost 40 horsepower to the car's already impressive output.
The B2K program spawned a succession of Callaway turbo Vettes, most notably the 880hp Sledgehammer. Reeves recognized that part of the beauty of boosted cars lay in the fact that, when properly built, they could essentially have an adjustable top speed. Engineers could dial in whatever power level might be needed for a given test, without ever showing a car's full potential.
And so, together with Chevrolet, Callaway decided to build a Corvette capable of dominating any of the top-speed contests popular with car magazines at the time. In this regard, the Sledgehammer proved an unqualified success: In October of 1988, it reached an astounding 254.76 mph at the Transportation Research Center in Ohio.
The outrageous, 255-mph Sledgehammer presaged the end of the Twin Turbo era at Callaway.
The Sledgehammer also prefaced the end of the Twin Turbo era. By 1991, the program had grown into something much larger than just an engine package-adding wheels, tires, suspension work, a custom interior, and the stunning Paul Deutschman-designed AeroBody. The price of a fully loaded car had climbed to almost $90,000, just as the U.S. economy was taking a turn for the worse.
Other factors were also at work. All of Chevrolet's marketing muscle was being thrown behind the "King of the Hill" ZR-1. The new-for-'92 LT1 base engine-with its revised architecture and reverse-flow cooling system-was proving to be a less-than-ideal candidate for turbocharging.
Callaway was approaching the 500 mark for total B2K production, but by 1990, orders had shrunk to fewer than 50. So, together with GM, Reeves decided to cease production at 500 units. The decision resulted in a huge outcry from performance-minded Corvette fans, some of whom had been saving for years in the hopes of sampling a boosted Callaway Vette. Despite numerous requests to extend the run, Callaway built its last B2K car during the '91 model year.
Today, the Callaway Twin Turbo cars represent a very special piece of Corvette performance history. Looking back to 1987, it's hard not to marvel at how the whole project came about.