Anytime you make a lot of changes to a project, you take a chance on something going wrong. It could be something as simple as forgetting to plug in a senor or something more significant — like a mechanical problem. In the case of our C6 Corvette project, we didn’t even know we had a problem until after a successful dyno session.
The new powerplant in our C6 consists of a Chevrolet Performance LSX 376 crate engine mated to a ProCharger Stage-2 D-1SC system. This combination, with 13-pounds of boost and a conservative tune, cranked out 653 rear-wheel horsepower and 646 lb-ft of torque at the wheels, running 91 octane gas. While we had intentions of bringing the car back for a more aggressive tuning session, we ran into an issue.
Before our second dyno session at Powerlabs, Brian Petty, owner of the C6, took the boosted ‘Vette for a spin and, everything seemed normal. But, when Brian stepped on the throttle, he found a problem. Under power, the Corvette would shift from First gear to Third gear, bypassing Second altogether. Even though it felt fine at part throttle, it was apparent that 6L80E was doomed and in need of a rebuild. We made a call to Hughes Performance to get the transmission whipped back into shape.
Since the transmission had to be rebuilt, Brian decided to go with the no-holds-barred approach and get the best six-speed transmission and torque convertor Hughes had to offer. The built 6L80E is rated at 1,000 horsepower and will ensure that no matter how much boost we might throw at the current combination, we do not need to worry about transmission failure again. Hughes was on the ball as usual, and Brian had the new transmission and convertor at his door within a few days.
With the new driveline back in its proper place, it was time to hit the rollers once again. On the first pull, we were able to make 643.5 horsepower 671 lb-ft of torque at 5,000 rpm, putting the C6 right where we left off during our previous dyno session. For the next pull, Jeremy Bird of Powerlabs decided to add more fuel and RPM. With an additional two-degrees of timing and a pull to 6,500 rpm, the ProCharged 376 cranked out 706.7 horsepower and 675 lb-ft of torque. All this while still drinking 91-octane pump gas and using a low boost number. For dyno run number three, Jeremy cleaned up the fueling and everything else remained the same. This change netted more gains, sending the horsepower to 735. The torque rocketed to 704.5 lb-ft.
While we’re thrilled with the performance of the ProCharged LSX 376 and the new Hughes Performance transmission, we have more in store. Our plans include switching out the runners in the FAST LSXR intake manifold, upping the boost, and comparing VP Racing Fuel’s MS109 racing fuel and E85 on the dyno. Who knows, we might even install a larger ProCharger to really see what this combination is capable of producing.