GM?s ZR1 Corvette has recently hit the ?Ring and as reported to be cranking out lap times in the low 7:40?s ? a seriously quick time that sees the mighty Vette trounce many an exotic supercar. Until now, GM have remained tight lipped on the ZR1?s LS9 engines output but have today revealed the supercharged 6.2-litre V8 pumps out an extraordinary 476kW/638hp and 819Nm. The hot lap times are no longer a mystery.
The LS9 is the most powerful engine ever released by GM and although a pushrod design there is plenty of high-tech involved in the building of this engine. GM hand build each LS9 at their Performance Build Centre in Wixom, Michigan alongside the LS1 7.0-litre found in the ZO6 Corvette.
Each LS9 features a super-strong forged steel crankshaft with a nine-bolt flange connected to forged aluminium pistons via titanium connecting rods. Even the heads feature strong and lightweight sodium filled titanium exhaust valves. Like the LS1, the LS9 features a dry sump lubrication system but unlike the LS1, there is a positive-displacement Roots-type supercharge sitting in the engines ?V?.
The supercharger is said to be a quiet achiever that goes about supplying up to 10.5psi without excessive whine. The final ?secret? that GM are holding onto is the fuel efficiency of the LS9, which may be lacking the high tech spec sheet of the big cube German V8?s but is believed to lead the pack when it comes to fuel efficiency for engines of similar outputs.