The Callaway Twin Turbo Corvette Timeline

In the late 1980's, international race car driver Reeves Callaway was running a successful business of turbocharging various high performance europeran cars (Porsche). At the same time, GM was struggling with ways to boost performance of the recently introduced C4 Corvette to improve sales which had declined due to increasing Federal Emission constraints. GM was already experimenting with various techniques including turbocharging as well as DOHC engines. GM took note of Reeve's turbocharging work and approached him to improve the turbo design they were working on (while they continued development of the LT-5 engine).

The Callaway Twin Turbo Corvette was available from 1987-1991 as option (RPO) B2K and could be ordered from select dealers in the US. Corvettes with this B2K option were then delivered to Callaway Cars in Old Lyme, Connecticut for the Twin Turbo conversion.

Once converted and tested, the cars were then shipped to dealers for delivery. Dealer repairs of the Callaway Twin Turbo option were covered by the standard GM, 12 mo/12,000 mile warrantee with Callaway Cars, Inc. reimbursing the dealers for time and materials on repairs. This was the first and only time where GM has had a factory orderable non-GM performance enhancement on the Corvette.

The ultimate Callaway Twin Turbo is known as the Sledgehammer (2 pictures shown above) which until 1999 held American production car speed record of 254.76 MPH, and its an emmissions compliant street legal vehicle with all the creature comforts lile A/C, Radio, etc that you would find in any production street corvette. It was built during the first production year of the B2K (1987) and was built from a 1988 Corvette Coupe. In addition to the engine performance improvements, the Sledgehammer Corvette used modifications to the body panels for reduced drag and improved stability. This body modification was designed by Paul Deutschman and was known as the Aerobody. The Aerobody was later available as another option to B2K ordered cars. (could my car be the one featured at Deutschman's website, halfway down the page?)

On the performance side, the 1987 production version of the Callaway TwinTurbo B2K option provided 345 HP / 465 Ft. Lb of Torque, on a stock car with a top speed of 178 MPH, at a price of just over $50K. In those days, this brought the Corvette into the performance category of Ferarri and Lamborghini which cost in the range of $100-$175K.

For 1988, Callaway increased the stock performance of the Twin Turbo corvette, producing 382 HP / 586 Ft. Lbs Torque. The first 64 cars of the 1988 production were equipped with a reworked but uncertified dual exhaust which produced 420 HP / 606 Ft. Lbs. of torque. Callaway recalled all these cars because the exhaust system was not considered legal (and 7 of the cars declined the exhaust change that was required by the EPA.)

The 1988 B2K was also optioned on only 7 of the 35th Anniversary cars; 4 with the 4+3 manual transmission, 3 with automatic transmission. One of the rarest Corvettes ever built. On the performance front, as the years passed Callaway continued to increase the performance of the B2K option. By 1991, the stock Callaway Twin Turbo Corvette produced 403 HP / 575 Ft Lb of Torque, providing a top speed of 192 MPH. For a detailed, year by year list of Callaway Corvette performance specs click on the link at the left panel. Performance Specs.

In 1990, GM introduced the ZR-1 Corvette which obtained similar performance characteristics as the Callaway Twin-Turbo option (and at a similar price) with a normally aspirated engine beginning the demise of the Twin Turbo B2K. However, before the Callaway TwinTurbo option went away, Callaway and Deutschman went to work to provide yet a more powerful and stunning car, the Callaway Speedster, my favorite of all Corvettes.

I took the pictures below of the Sledgehammer along with other spectacular Callaway Corvettes which were auctioned off during the famous Barrett-Jackson auto auction in January 2004. (Click on any picture to enlarge)

The GM contract with Callaway for factory ordered (B2K) Callaway Twin Turbo corvettes concluded in the 1991 production year. At that time, GM focused its efforts on promoting the ZR-1 Corvette which was naturally aspirated and internally produced by GM in cooperation with Lotus which designed the LT5 engine and Mercury Marine that manufactured the blocks. Callaway continued to provide aftermarket conversion of L98 Twin Turbo Corvettes, but with the market focusing on the ZR1 the emphasis was on commissioned cars that besides various levels of performance, the owner could choose custom paint schemes as well as matching or colored Connolly leather interiors tailored to the owners taste.

The culmination of power improvements through turbo charging along with various styling efforts developed into a series of Callaway Twin Turbo Speedsters, perhaps my favorite form of the Twin Turbo. The prototype Speedster, #001 was in custom Callaway Old Lyme Green. A total of 11 Callaway Twin Turbo Speedsters were created, the last one completed in 2004 for Mrs. Reeves Callaway.

Callaway Cars has since provided other engineering development for racing and other auto companies including Aston Martin, Land Rover, Holden Cars, and Mazda. For more information, please visit the Callaway Cars website. Here are some pictures of more recent Callaway Corvette products since the GM RPO B2K program: (click on any picture to enlarge)

Callaway Twin Turbo Racer

LT1 Naturally Aspirated (SuperNatural)

LT5 Callaway Lemans ZR-1 (CR-1)

LT5 Twin Turbo (SuperSpeedster)

C7R Racer

Callaway C-12 (Leman's regulation car)

a speedster version of the C12

and all ALL carbon fiber C12 with a dark blue clear coat - the carbon fiber looks like a tailored suit, a spectacular & rare sight to see

Callaway Carlisle Corvette (C36)

Callaway Supercharched Corvettes (560HP for LS2 and 580HP for LS3)

Callaway C16 Coupe (616HP for LS2 and 650HP for LS3)

Callaway C16 Cabrio (616HP for LS2 and 650HP for LS3)

Callaway C16 Speedster (700HP LS3)

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