Effective intercooling allows...
Effective intercooling allows the blower to safely run up to 6 psi of boost on premium pump gas.
Modifying the fuel pump depends on the customer's individual application. Magnuson's Kerry Tresback points out that if a Z06 Vette is left in a strictly stock configuration (with the exception of the supercharger), increasing the pump output by stepping up the voltage with a MagnaVolt unit is not strictly necessary. However, since many Vette owners modify their engines with a hotter cam, headers, and so forth, Magnuson will be including the MagnaVolt component with the Z06 Corvette supercharger system in order to ensure sufficient fuel volume.
As for the intercooler, virtually all superchargers benefit from reducing heat during compression. A decrease in intake-air temperature provides a denser charge to the engine and allows more air and fuel to be combusted per engine cycle, increasing output. In addition, a cooler intake charge allows for higher boost levels without detonation, producing more power.
Note however, that all engines running on pump gas are compression limited. When you add boost to an engine, you are essentially adding compression. Regardless of supercharger style, there is a limit that, if exceeded, can destroy the engine. With 92- or 93-octane pump gas, that limit seems to be 7.5 psi with an effective intercooler.
Despite the modest boost level,...
Despite the modest boost level, the Magnuson package bumped the output of Steven Young's Z06 from 450 to 573 hp at the rear wheels. Torque is similarly massive, cresting at just under 515 lb-ft.
With the improved efficiencies of Easton's new lobe design, however, lower boost levels (about 4 to 5 pounds in this application) can still furnish exhilarating performance. As Roese points out, "It takes less horsepower to power the unit, so the parasitic numbers are lower, the discharge temperatures are lower. Adiabatic efficiency is the key." The added bonus is less stress on the engine block. (And yes, we've heard too many sad tales about the "best-laid plans of mice and men" going astray due to extremes of forced induction.)
Young has some key words of his own to describe the change from naturally aspirated to a supercharged mill: "Before, it was a very tractable, even docile, street car, but turned into King Kong when I hit the throttle hard. [It's still] equally docile and tractable-no difference at all in street driving-but now when you hit the throttle, it turns into Godzilla. The ZR1s out there can't touch it."
So he's saying there's not just one, but two big bad monsters in one car. We can vouch for this experience personally after stomping on the go pedal. The traction control kicks in pretty quick, so this supercharger has plenty of fire breathing and chest pounding to spare.
"A horse, a horse! My kingdom for a horse!" Richard The Third, Act 5, scene 4
So how much more output are we talking about here? Unlike the hunchbacked villain-king Richard III, who was about to meet his doom at the hands of the future Henry VII, we want more than just a single horse. How many can you corral with a Magnuson 2300 TVS supercharger? According to a company dyno graph, the peak horsepower jumps from a stock figure of 450 to 573.4 hp. That's a gain of 123 horses, more than 27 percent.
Of course, much higher levels are possible with a smaller pulley (2.9 inches is the minimum), but Roese notes that the high compression of the LS7 might require taking some timing out and losing throttle response. So this level strikes a happy balance between driveability and whup-ass acceleration. Case closed.