Longtime Corvette disciple Michael Razzano finds inner peace in a twin-turbo, 1,000-hp C7

Photo: Zen-06 1
December 26, 2019

New Yorker Michael Razzano grew up in an automobile-centric household, so it’s hardly surprisingly that he’s been fixated on cars for as long as he can remember. “Ever since I was a young child,” he recalls, “I was fascinated with American muscle cars in general, and Corvettes in particular.” The very first automobile that left the youngster speechless was a 1956 Corvette he saw at a car show, and to this day that model remains a favorite.

When Razzano was finally in a position to buy his own Corvette, however, his love for speed and all-around stupendous performance overshadowed nostalgic feelings for the red-on-red ’56 that left such a lasting impression. “I loved the off-the-factory-floor power of the C7,” he explains, “but to be honest, I was not in love with every aspect of the car. The performance was great with the LT4 motor, [as were] the interior upgrades…but I really didn’t like the looks of the rear of the car.” The rear styling of the Z06 model would grow on Razzano, however, and eventually he started looking for one of these supercharged C7s.

After about seven months of looking, Razzano found exactly what he wanted: a one-owner, 3,000-mile, Laguna Blue 2015 Z06 with the 3LZ package and a seven-speed manual gearbox. The car was bone stock and had clearly been babied from day one, providing a perfect starting point for his high-performance build.

Photo: Zen-06 2

“When I bought the car, I knew a lot of guys who increased performance by putting on a larger supercharger, but I wanted something different,” he says. “That’s when the idea of installing twin turbos on the engine came up. As a mechanical engineer, my passion is to optimize everything to its fullest potential, and the idea of designing a turbo setup seemed like a great way to go.”

To bring his vision for the car to reality, Razzano turned to the experts at JTM Motorsports, a Deer Park, New York, shop that specializes in performance modifications for Corvettes and other late-model GM vehicles. Working within the parameters Razzano established for the build, the techs at JTM put together a twin-turbo package designed around two Bullseye Power Street Billet Series 66mm turbos. Each unit was assigned a blow-off valve and wastegate, both of which were sourced from Turbosmart. The turbos were also wrapped with an insulating blanket and mated with an air-to-air intercooler, the latter fabricated by JTM using 4×10-inch aluminum cores from Bell Intercoolers. All of the plumbing and mounting brackets required for the installation, as well as the exhaust headers, were also custom made in-house by the shop.

While the LT4 engine’s cylinder case, cylinder-head castings, and bottom-end reciprocating assembly were left completely stock, JTM made a host of upgrades to many of the powerplant’s other parts. BTR valve springs and pushrods, along with Johnson lifters, replaced their stock counterparts. The stock LT4 intake yielded to a Holley Performance Products MSD Atomic Airforce manifold, which is molded from a strong polymer to minimize both weight and heat buildup. This intake was designed for installation on the LS family of engines and is not a direct fit for an LT4, so the techs at JTM had to use special spacers for Razzano’s application.

Photo: Zen-06 3

Because E85 tends to yield a cooler air/fuel mixture, thus increasing knock resistance and overall performance, Razzano’s car was converted to run on this ethanol-laced fuel. And because the C7’s stock fuel system can’t provide quite enough volume to accompany the boosted air supply, JTM further modified it by adding an auxiliary delivery setup, consisting of Injector Dynamics 1050X injectors on the engine’s port side. This system utilizes special injectors developed through a partnership between Injector Dynamics and Bosch Motorsport.

To take full advantage of the greater air/fuel volume, JTM had a new 8620 steel alloy LTx Turbo camshaft blank custom ground to their specifications by Cam Motion.

In keeping with Razzano’s desire to dramatically increase his Corvette’s performance while simultaneously maintaining its civility, the car’s stock ECU was retained, albeit with a revised tune to accommodate all of the engine modifications that were done. Additionally, a Prospeed Autosports auxiliary control module (ACM) was installed to control the fuel system.

Photo: Zen-06 4

For street driving, Razzano had Mickey Thompson ET Street S/S rubber mounted on 18-inch Signature SV101 rims, which were forged from T6061 aluminum. The rear tires are sized at 345/35R18, and the fronts measure 305/35R18. For drag-strip action, he uses the stock Chevrolet rims in the front, along with 285/30R19 Continentals. Meanwhile, a 15×10-inch set of Weld Racing S77 rims resides in the rear, paired with 275-series Mickey Thompson ET Street Radial Pros.

In the front, the car retains stock Z06 brakes, including the carbon-ceramic rotors and OEM calipers. In the rear, the brake system, along with some of the factory suspension parts, were replaced with a Carlyle Racing C7 15” conversion kit. The kit enables the installation of 15-inch-diameter rear wheels, which can be advantageous at the track. It includes solid 15-inch rotors, which Razzano upgraded to slotted-and-drilled units, along with four-piston Wilwood calipers and adjustable lower control arms. The remainder of the rear suspension, and all of the front setup, remain stock.

With a very conservative tune, and an equally conservative (for an E85 car) 19 pounds of boost from the Bullseye turbos, the upgraded LT4 channels a bit more than 1,000 horsepower and 850 lb-ft of torque to the rear wheels. JTM owner John Mondouros believes the engine could handle even more boost in its current configuration—but only up to a point. “It [currently] makes plenty of power, and we know the stock bottom end can tolerate that without any problems. A few more pounds would not hurt it, but after you go over about 25 psi, you need to build a stronger engine from top to bottom.”

Photo: Zen-06 5

With significantly increased boost, Razzano would also need a new transmission, differential, driveshaft, and related driveline components. Right now, he’s still using the car’s original 3.42:1 final-drive-ratio transaxle and other driveline parts, with the only upgrade being an RPS Billet Triple Carbon clutch setup. This unit uses three full carbon discs, a billet-aluminum cover and pressure plate, and a CNC-machined billet-steel flywheel. It’s rated to handle up to 1,400 horsepower and 1,200 lb-ft of torque at the rear wheels, providing a healthy margin of safety even when paired with Razzano’s heavily boosted LT4.

Razzano was happy to significantly alter his engine for increased performance, but he wanted to keep the car’s appearance mostly original. Even so, he did make a number of changes to both the exterior and interior. On the outside, carbon-fiber front-wheel trim moldings, mirrors, mirror mounts, side skirts, fender vents, and a hood vent replace their stock Chevy counterparts. An Ivan Tampi Customs carbon-fiber rear diffuser and custom Z06 “Twin Turbo” badges inset into the front fender vents further distinguish the Corvette’s body.

Inside the car, the most obvious change is the substitution of a custom Carbon Fiber Element steering wheel for the assembly-line wheel. The stock instrumentation was retained, but augmented with a Pro EFI display to monitor a long list of parameters, including the engine’s air/fuel ratio, ethanol content, fuel pressure, manifold pressure, wastegate set points, exhaust backpressure, coolant temperature, oil temperature and pressure, and more. The final addition to the interior was a custom badge beneath the HVAC controls, calling out the engine’s dyno-verified horsepower and torque figures.

Photo: Zen-06 6

Although Razzano has considered further modifying the Z06’s engine and drivetrain for better quarter-mile performance, he’s concerned that getting to the “next level” on track will necessarily diminish the car’s drivability on the street. So for now, he’s content to do the best he can with it, and to enjoy it as much as possible.

“In the words of the great Jackie Stewart,” he reflects, “‘It’s not always possible to be the best, but it is always possible to improve your own performance.’ For me, that’s what cars and racing are about: my desire to push my own limits and improve my performance, and to have as much fun with this car as I can. I find this very gratifying and a means to inner peace.

“I also look forward to sharing the car with my son, Matteo, in the future,” he adds. “He’s only a year old, but he already has an appreciation for Corvettes, courtesy of his own little electric C7 Corvette, which we made Laguna Blue with a wrap and modified with cross-drilled rotors, painted rims, operable lights, dummy twin turbos, and an upgraded 24-volt power supply.”

Photo: Zen-06 7

And so the Razzano family’s enduring bond with America’s Sports Car continues to deepen, one Corvette at a time.

Also from Issue 135

  • Tech: C8 Dual-Clutch Automatic
  • Couple-Owned C2 Duo
  • 600-Mile C3 Road Trip
  • Market Report: C1
  • Found: '89 ZR-1 Prototype
  • Racing: C7.R Retrospective
  • LS3-Powered C1 Restomod
Like us on:   Facebook icon