i'm building an iroc camaro with twin turbos, i bought the turbo setup already and everything else like oil pump fuel pump etc. now i just need to build my 350 so i figured the callaway used the tpi setup to so if someone can give me all the engine specs like cam duration, pistons, head cc, i do know they used aluminum heads but i dunno port size or anything so if anyone could help it would be greatly appeciated

 

 

7.5:1!?

I wonder what they used on the sledgehammer. What block, heads, boost level, and induction system...anywhere I can find that?

 

On the '88+ cars the boost was 56" Hg absolute (iirc), which I think is around 12.5psi of boost? They used the GM block, heads, and TPI, though the very first cars had truck blocks. Since the engine conversion took time, a car did not get the engine it left BG with put back in, rather the engine that came out of an earlier car.

I believe the later 450hp engines used in the speedsters and a few '91 B2K's had an 8.5:1 compression ratio, and used stronger rods and pistons?

I don't think they did any port or combustion chamber work really. The initial idea was to boost the stock block. But in order for the engines to hold together and be durable, Callaway had to check the blocks and upgrade the rotating parts. I actually didn't realize they used a different cam or did anything to the heads, but that list says otherwise.

 

Also just FYI, but on the topic of the OP, there's a forum here about forced induction: http://forums.corvetteforum.com/forumdisplay.php?f=87

I imagine that would be more help in terms of you getting your car together and running than some specs on what Callaway did.

 

The Sledge Hammers engine was built by John Lingenfelters shop. I cut and pasted the specs from D. Randy Riggs' artical which appeared in Vette Magazine back in 1989.


The team began with a Bowtie block with four-bolt caps and a Cosworth SIGMA finished crank, cross-drilled to facilitate rod oiling for high loads. Clevite 77 bearings were fitted. A Houdaille fluid damper was used, in standard Corvette diameter, to clear discharge pipes. Crower rods were also fitted, along with Jesel roller rockers with a Jesel stud girdle. Crane supplied the roller lifters.

Oiling is via an in-pan-style Barnes dry-sump system, which holds l0 quarts of Mobil l synthetic, the brand specified in production Callaway cars. The tank fits in the spot normally occupied by the
HVAC (heating/ventilation/air conditioning) system, now moved to the right rear storage compartment in a custom-built arrangement. Oil cooling is provided by coolers mounted in the nose on each side of the car.

Cosworth pistons were specially made for Sledgehammer. Jeff Roper, experienced in running Turbo Buick V6 motors at Indy, designed them, with Buick Indy motor skirts. Speed Pro plasma moly rings were fitted.

Cam Techniques supplied the camshaft. which was designed by Dave Generous. Surprisingly, the cam is not that aggressive, but very special to aid highway performance. Brodix supplied the No. 12 heads, which were drilled and tapped to accept standard Callaway front engine dress. The heads were O ringed, copper gaskets were fitted, and studs, instead of bolts, were used for retention.

898 horsepower; 6200 rpm in fifth Overdrive equals 254.76 mph!

Callaway Corvettes are famous for their twin-turbo design, and that concept carries through to the Sledgehammer. Originally, they had planned to use a mirror image of their current system, but
they dropped that plan in favor of a design that they could package on the upcoming ZR1 (yes, gang, a twin-turbo ZR1 will be coming from Callaway!).

Huge Turbonetics T04B-series turbos were used with R. Lee stainless steel wastegates. The wastegates can be controlled electronically, through an electronic pressure regulator, or manually,
through a boost **** in the cockpit. Boost is set at 1.5 bar, or 22 psi. Individual stainless exhaust headers were built at Callaway.

Additionally it dosen't say anything about the intake manifold but I have seen the intake and it is a TPI Plenum that they welded the sides of closed and then cut the bottom open and welded it to a shortened sheet metal ram base (overall it ended up much like the Stealth Ram). Here is a PIC



It's interesting to know they made that much HP using the pretty small TO4B compressors but with 2 of them it was obviously enough. Other side notes the -12 Brodix's are 15 degree valve angle and back in 89 they were cutting edge race car stuff. The Barnes "in the pan" dry sumps were one of the best packaged dry sump systems ever made, too bad Barnes quit making them, but it too was cutting edge back in 89. This car had the best stuff money could buy back then. Lingenfelter pretty much took a small displacement NDRA Super Late Model engine, dropped the compression ratio and stuck fuel injection with turbos on it.

Will

 

Thanks for all that info! If you watch the video about the sledgehammer, you'll see a blue corvette (my color) with a white hard top in the background! Wonder whats up with that!

I need to do some digging about that.

Just imagine what they could have done with that car if they built it now with all the new technology!

 

There is info (like the sheet Aurora40 posted) from www.callawayownersgroup.com however, cam specs were stock Corvette on the B2K RPO

The Sledgehammer story has been told in error for so long - It was a Callaway assembled engine that powered the car for the record run, period.

 

Why? Has there been another Corvette, faster? No. Not even the ones with estimated, or asterisk "top speeds"

 

That's what I'd thought. But that list has one of the items on there "steel roller camshaft and hydraulic roller lifters"? Does that just mean the car has one, but it's the stock one?