Of course, all this technology has to work together to maximize power gains and minimize problems. To that end, Lethal relies on its tuning expert, Shawn Behrendt, who uses HP Tuners equipment to set timing, fuel load and other parameters. The final dyno run revealed the modified LS9 was putting out 753 horsepower at the rear wheels, a whopping 42-percent improvement over stock without any internal head or blower modifications. And, according to Gonzales, the ZR1 is still eminently streetable.
To back up this powerhouse, Lethal replaced the standard twin-disc clutch and flywheel assembly with a three-disc RPS system that uses a special steel flywheel that bolts to the ZR1’s unique 9-bolt crank flange. Unlike some performance clutches, says Gonzales, it has a soft pedal feel and is a pleasure to drive on the street. Lethal also added a Quick Time scattershield to contain the debris should there be a clutch or flywheel failure.
Gonzales opted to change the rolling stock, switching to Forgedstar F14 rims measuring 10 × 19 inches in front and 12 × 19 inches in the rear (the ZR1 comes with 10 × 19-inch and 12 × 20-inch wheels). While the front Nitto Invo tires are the same 285/30ZR19 size as the ZR1’s stock Michelins, the Nitto NT05R rears are slightly wider at 345/30ZR19 versus 335/25ZR20. The slightly taller sidewalls of the 19-inch tires help them hook up better off the line compared to the standard 20-inchers.
When it came to the ZR1’s brakes, Lethal left well enough alone: You just can’t improve upon the car’s massive carbon-ceramic binders. The same was true of the suspension: The car’s Magnetic Ride Control shocks provided all the damping required for Lethal’s straight-line runs. However, given the car’s speed potential, it did see fit to install a Pfadt roll cage and racing harnesses.
With the silver rocket primed and ready to fire, Lethal took it to the nearest drag strip. At San Antonio Raceway (SAR), Gonzales turned a 9.93-second quarter-mile time with a terminal velocity of 148.9 mph. The 9-second goal had been reached, but the Lethal team wanted more. Later, it brought the Corvette back to SAR and ran a blistering 9.90-second run at 150 mph! A week later, it got the ET down to 9.713 seconds at Royal Purple Raceway in Baytown, Texas. This was good enough to make the silver car one of the quickest street-legal ZR1s in the country.
Quarter-mile times are all well and good, but down South one of the most hotly contested tests for bragging rights is the Texas Mile top-speed run held in Beeville, near San Antonio. Contestants line up on a mile-long stretch of runway at Chase Field Industrial Complex just outside of town. The track is smooth, but not pool-table smooth; there are two dips pronounced enough to cause problems for the unwary, and they can be particularly scary for kamikaze motorcycle pilots. The timing trap where top speed is read is placed in the final 132 feet of the track, insuring that the fastest cars have to run the full mile. This leaves out pure dragsters.