One-of-a-kind Corvette that hit 255 mph in 1988 heads to auction

Shawn Knight

Posts: 13,167   +132
Staff member
In a nutshell: One of the most iconic cars in automotive history has recently come up for auction and if you’ve got deep enough pockets, it could be yours. The one-off SledgeHammer was designed to set a production car top-speed record while maintaining the creature comforts of a typical street car. That means it kept things like the stereo system and air conditioning, components that typically get removed in high-performance cars to reduce overall weight.

As the story goes, Corvette tuner Callaway Cars ordered this 1988 Corvette coupe new from a dealership and had it sent to Callaway Engineering in Old Lyme, Connecticut, for modification. There, it became the 51st Callaway Twin Turbo Corvette of that year and eventually, the donor car for Project SledgeHammer.

Under the hood is a hand-built twin-turbocharged and intercooled 5.7-liter V8 that was rated by Callaway Cars at 880 horsepower and 772 lb-ft of torque.

In October 1988 at a test track in Ohio, the SledgeHammer reached a top speed of 254.76 mph with legendary NHRA driver John Lingenfelter behind the wheel. That’s an incredibly impressive top speed, even for today. For comparison, Koenigsegg hit 277.9 mph with its Agera RS hypercar in 2017. Callaway was doing this more than 30 years earlier.

That very same car is now up for auction over on Bring a Trailer. According to the listing, the vehicle now has 2,000 miles on the odometer and has been stored in a “museum environment” for most of its life since the record-breaking run. In 2018, Callaway Cars replaced the vehicle’s hoses, couplings and fittings.

The current bid is $425,476 and with nine days remaining, the price is likely to go much higher.

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psycros

Posts: 3,452   +4,010
I'm OK with this article because automotive tech is at least as complex and interesting (to car people, anyway) as stuff like computers or phones, and in modern times the two have become heavily intertwined. Even the mass production cars of today are completely reliant upon computer-driven management of nearly every system. Its impressive to think that the Sledgehammer 'vette probably only had a handful of chips running sensors and maybe the stereo system. Even back then you could still monitor a good bit of feedback from many cars but most of the tuning was still done manually. Imagine if Clarkson had known about THAT Corvette.
 

Adhmuz

Posts: 2,148   +948
Neat, I've known about the Callaway Sledgehammer only due to GranTurismo, nice to hear the back story all these years later.
 

Dimitrios

Posts: 779   +605
Great article but only because I live in CT and I love Corvette's lol. Got a 1999 Camaro SS with the LS1 and running HP tuners software on my laptop. I do all the tuning of the PCM myself. She's got over 180,000 miles and finally have time for getting classic plates.
 

captaincranky

Posts: 16,755   +5,486
All things being considered, Corvettes need to be painted red:
1963_Corvette_Stingray_Split_Window.jpg
 

wiyosaya

Posts: 5,911   +4,154
I am sure some dolt with excess pocket change will be happy to fork over a sizeable chunk of money for this one. :rolleyes:
 
I read car magazines for more than 30 years. This was one car that really impressed me. It was driven from Connecticut to Ohio and back to Connecticut after it's record run. It was an incredibly rare car that could go so fast yet still be used on public roads. It was also a good example of what turbocharging will do for a car's power.

Another thing I always found interesting was the Callaway Twin Turbo Vette for sale to customers produced over 500 ft*lbs of torque at less than 2000 rpms. I wish I could have afforded a Callaway car.

For those more interested in European cars. Callaway also modified Alfa Romeo GTVs back then.
 

captaincranky

Posts: 16,755   +5,486
I am sure some dolt with excess pocket change will be happy to fork over a sizeable chunk of money for this one. :rolleyes:
Nah, more likely a balding dude suffering from a severe "mid life crisis" / male menopause.

You know, the "Robert Picardo hairline":

Robert-Picardo-DST-Germany2020.jpg


In fact, it almost looks like he's contemplating buying that car this very minute. :rolleyes::
 

sorten

Posts: 81   +119
I remember the Sledgehammer. Cool car, for a Corvette.

There's no reason to delete the stereo, carpet, and other interior comforts for a top speed run. That's only done for track cars. At anything above 60 or 70 mph, it's all about power and aerodynamics. (edit) and gearing.
 

Squid Surprise

Posts: 4,030   +3,157
I remember the Sledgehammer. Cool car, for a Corvette.

There's no reason to delete the stereo, carpet, and other interior comforts for a top speed run. That's only done for track cars. At anything above 60 or 70 mph, it's all about power and aerodynamics. (edit) and gearing.
Well, there is... if you want the absolute fastest speed possible... weight is always an issue... the lighter, the faster... but assuming you intend to enjoy your car, it’s worth it to sacrifice a mile per hour or two of speed in order to be more comfortable:)
 

Adhmuz

Posts: 2,148   +948
Well, there is... if you want the absolute fastest speed possible... weight is always an issue... the lighter, the faster... but assuming you intend to enjoy your car, it’s worth it to sacrifice a mile per hour or two of speed in order to be more comfortable:)
I'm no physicist however wouldn't it stand to reason a heavier car would require less down forced generated by aerodynamics to maintain wheel traction as speed increases? As aerodynamic down force generated by a wing would be increasing proportionally the faster you go you could theoretically have a cross over point where the heavier car with less aerodynamically generated down force would be applying less downwards force to the ground vs the lighter car with more aerodynamically generated down force resulting in lower rolling resistance and a higher top speed for the heavier car.
 

Squid Surprise

Posts: 4,030   +3,157
I'm no physicist however wouldn't it stand to reason a heavier car would require less down forced generated by aerodynamics to maintain wheel traction as speed increases? As aerodynamic down force generated by a wing would be increasing proportionally the faster you go you could theoretically have a cross over point where the heavier car with less aerodynamically generated down force would be applying less downwards force to the ground vs the lighter car with more aerodynamically generated down force resulting in lower rolling resistance and a higher top speed for the heavier car.
Yes... a certain amount of weight is necessary.... but friction (and the reduction of it) is the main obstacle cars face when attempting to go super fast... and the heavier they are, the more there is...

There's a reason most race cars are built as light as possible...
 
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Adhmuz

Posts: 2,148   +948
Yes... a certain amount of weight is necessary.... but friction (and the reduction of it) is the main obstacle cars face when attempting to go super fast... and the heavier they are, the more their is...

There's a reason most race cars are built as light as possible...
Track cars designed to corner at high speeds, absolutely weight is what you are trying to eliminate as much as possible, this will decrease deceleration time entering the corner, allow for faster cornering, and then increase the speed at which you can accelerate out of the corner.

When attempting top end straight line speed weight plays an important role in stability of the vehicle which would other wise need to be generated by down force, the more weight already present, the less down force would be required to be generated aerodynamically. Keep in mind these elements that generate down force also contribute greatly to the drag coefficient of the vehicle, something that plays a far larger role in the limitation of the top speed then that of the friction generated by the tires of a heavier vehicle.

What I was suggesting is as the weight of the vehicle is higher, less down force would need to be generated, which also would result in less drag being produced. As the generation of down force will increase with higher speed proportionally there will be a point where the the downward force of the lighter vehicle with more aerodynamically generated down force will surpass that of the heavier vehicle with less aero resulting in higher friction generated by the tires in the lighter vehicle at higher speeds.
 

Squid Surprise

Posts: 4,030   +3,157
Track cars designed to corner at high speeds, absolutely weight is what you are trying to eliminate as much as possible, this will decrease deceleration time entering the corner, allow for faster cornering, and then increase the speed at which you can accelerate out of the corner.

When attempting top end straight line speed weight plays an important role in stability of the vehicle which would other wise need to be generated by down force, the more weight already present, the less down force would be required to be generated aerodynamically. Keep in mind these elements that generate down force also contribute greatly to the drag coefficient of the vehicle, something that plays a far larger role in the limitation of the top speed then that of the friction generated by the tires of a heavier vehicle.

What I was suggesting is as the weight of the vehicle is higher, less down force would need to be generated, which also would result in less drag being produced. As the generation of down force will increase with higher speed proportionally there will be a point where the the downward force of the lighter vehicle with more aerodynamically generated down force will surpass that of the heavier vehicle with less aero resulting in higher friction generated by the tires in the lighter vehicle at higher speeds.
You are correct - but that point hasn't been reached with almost all cars.... they are still at the point of "make them lighter because lighter=faster".

The engineers who make them know what they're doing.... so I'm pretty sure there's a reason for eliminating all the extra weight they can :)