They say you can never be too rich or too thin--or have too much horsepower. You're on your own for the first two, but to address the third, Toyota Racing Development has introduced new supercharger systems for the 2007-2009 Tundra and new Sequoia equipped with the 5.7-liter V-8.
The TRD division chose an Eaton Roots-type supercharger Twin Vortices system with a liquid-to-air aftercooler that uses a low-temperature heat exchanger. A TRD performance air-intake system is included along with iridium spark plugs, high-flow injectors, and a high-capacity fuel pump. In addition, there's a TRD calibration that reflashes the engine-control computer and a tidy single-belt drive system. All kits are 50-state emissions legal.
The superchargers pump out a substantial 8.5 psi of boost, which really wakes up these engines. The 5.7-liter engine's horsepower is bumped 25 percent to a whopping 504 horses at 5500 rpm (up from 381). Torque also makes a sizeable jump by 27 percent to 550 pound-feet at 4000 revs (up from 401).
On the down side, premium fuel is required. Also, the TRD reps state that, in EPA-mileage testing (which is predominantly light-throttle low-speed driving) the supercharged engines get approximately the same fuel-economy numbers as stock. However, we should note that, in real-world driving, owners typically report about a 1 mpg loss. As usual, fuel economy depends on how you drive.
As part of its strength and durability testing, Toyota spent a lot of time towing with this particular full-size-truck performance upgrade. Towing aficionados know that a supercharger gets more air into the engine at higher altitudes and also helps when pulling a heavy load up a grade. Throughout testing, temperatures of key components were monitored, including the catalyst, transmission, intake, and coolant. Likewise, TRD has supercharger kits for other smaller vehicles like the current-gen Tacoma and FJ Cruiser. Performance gains for the 4.0-liter V-6 top out at 302 horsepower and 334 pound-feet of torque, up from 236 and 239, respectively.