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2006 Chevrolet Corvette Z06 - Dual In The Sun

Twin Turbos And 700 RWHP Make This Z06 Deadly Quick On The Draw

Steve Temple Feb 1, 2009
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Back in the '40s, the famous director David O. Selznick hoped to exceed his success of Gone With the Wind with a new movie, Duel in the Sun. Since the plot revolved around themes of prejudice and forbidden love, critics jokingly dubbed it "Lust in the Dust."

What does this brief filmography have to do with a twin-turbo Z06? Well, all of those titles could conceivably refer to Mark Rodriguez' project (allowing for slight change in spelling in reference to the dual turbos). After all, a Corvette smokin' the tires with 700 horses and pound-feet of torque-and the potential to break the 1,000 mark-would surely be an object of lust, as it disappears in a cloud of dust, and goes like the wind. (Sorry.)

OK, those movie clichs are really worn, but you get the point, right? And so did Rodriguez, since his object of desire was the mechanical kind, not the stuff of movie melodrama.

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"It wasn't about beating anyone or outdoing someone," he admits. "It was about me and what I wanted."

Let's cut to the details. In December 2006, Rodriguez began researching in earnest, doing his homework on what would later become one of the first twin-turbo C6 Zs on the planet.

That meant evaluating everything from a set of $6,000 All Pro Heads to a $1,700 Corsa exhaust. He went through three different clutches before finding the perfect fit with a Textralia twin-disc setup. The one Rodriguez chose is called the Exo-Skel, and it uses a relatively small diameter for a low MOI (Moment of Inertia). When combined with multiple discs, it provides the maximum amount of surface area possible in a small-diameter clutch. Bolstering that drivetrain upgrade are RPM's Level 5 diff and transmission. (Typically, anything above 500 horses requires a stronger clutch and rear stub axle.)

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After all, as Rodriguez points out, nothing could be left to chance when trying to achieve immense horsepower, since any miscalculation could carry with it dire consequences.

But Rodriguez wouldn't put up with any drama. "I wanted speed, but not at the cost of gutting the car and taking the essence away from what makes the Z06 stand out above the rest," he says. "The car still has many of the luxury features that it came with, like heated seats, the radio, and yes, even the A/C unit." So his ride still has broad entertainment value, rather than appealing to a narrow audience. Who were the cast of characters he chose?

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"To help me achieve my dream, I enlisted the help of none other than Kurt Urban [formerly of Wheel to Wheel Powertrain, and now with J&K Racing] to construct my over-the-top, fully built LS7 engine," he reveals. And in a key supporting role was that scientific genius, "Dr." Phil Hoelfer, the engineer behind Turbo Technology Inc.'s twin-turbo kit and a custom fuel system.

The dual setup, mounted low down near the oil-pan rail, consists of a Turbonetics T3/T4 configuration. There isn't enough room for a T4 turbo shell without tearing apart the engine bay, so the T3 housing is bored out to accept the larger T4 innards. With this configuration, the turbos didn't have to be mounted on top, which would otherwise clutter up the engine bay, produce more underhood heat, and make it virtually impossible to change the spark plugs without dropping out the engine. As a result, the only visible giveaways are the intercooler and the custom, ceramic-coated exhaust manifold. Completing the exhaust system are Corsa's Z06 converter-back system and a 3-inch cross-pipe.

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Originally, Turbo Technologies' goal was to produce in the neighborhood of 600 streetable horses, but customer demand for even more power impelled Hoelfer to come up with some other options. Given the dramatic increase in airflow from the parallel-series pinwheels, the company correspondingly dialed in about twice the amount of fuel with a set of 60-lb/hr injectors (the factory units are rated at about 28 pounds). A larger fuel pump is mounted in the tank as well.

To beef up the block to handle higher cylinder pressures, ERL sleeved it with thicker dry cylinder walls, and Urban dropped the compression to 8.5:1 with Diamond dished pistons and Howard rods spinning a Callies Magnum XL crank. A 224/224 cam bumps Jesel J2K rockers in the lighter Mohawk configuration, and these in turn are fitted into LSW All Pro Heads. ARP main studs and head studs clamp the lump together on a Fel-Pro five-layer race-duty head gasket.

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Those are just the hard parts. Next came a full day's worth of data logging to tweak the fuel maps using HP Tuners' VCM Editors Flash system. This utility allows the user to read the VCM/PCM flash memory and save it to a binary file for calibrating and modifying parameters such as spark, fuel, rpm limits, temperature, transmission shift points and pressures, speedometer settings, and so forth. This unit also features automatic recovery capabilities for protection against any reflashing problems that might be encountered.

To monitor the changes effected by the new software, precise instrumentation was added. These items include an HKS EVC 6 Boost Controller along with air/fuel, boost, and fuel-pressure gauges from Nexus. Even with all these precision mods, pulling out this much power on only 91 octane can be a risky business, so methanol injection was added to improve the burn without having to retard the timing too much.

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That turned out to be a really good thing, as demonstrated during one early-Sunday-morning burst of speed on the freeway that went well into triple digits. "It happens really, really fast," Rodriguez says. "It's overwhelming. The speedo needle jumps so easy, it can get you into big trouble." Considering how much power is on tap, it's no surprise that the next step in this project will probably be ZR1 brakes.

Once all was said and done, this performance plot had a happy ending. Commenting on all the folks involved in the project (Hoelfer, Urban, George and Nick at TT, and TJ and Rodney at RPM), Rodriguez was effusive in his praise: "Their care and attention to detail were surpassed only by their results. They worked their magic and, above everything else, put up with my incessant questions, phone calls, and emails. My hat is off to them-they took my dream and molded it to become sheer perfection."

Of course, we tend to be a bit more reserved when it comes to critical acclaim. After all, the car's the star here, right?



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