Compared to the rotors in the LT4’s supercharger, the LT5s are larger in diameter and have a unique, 170-degree pitch for the four-lobe design versus the previous TVS 160-degree pitch. The higher-pitch angle enhances the blower’s efficiency at high RPM, helping it sustain max boost through the top of the RPM band. (Photo Courtesy General Motors)
The Gen V Camaro ZL1’s LSA engine used a smaller, 1.7L TVS supercharger compared to the C6 ZR1’s larger 2.3L blower. The result was 580 factory-blown horsepower. (Photo Courtesy General Motors)
This photo shows the unique, four-lobe rotors of the Eaton TVS blower. The quartet of lobes combined with the high helix (rotor angle) design gives the blower a quasi-twin-screw look. That’s intentional because, similar to a twin-screw design, the TVS delivers greater performance at low and high RPM. (Photo Courtesy General Motors)
The Eaton compressor-based Magnuson bolt-on kits are very popular for C5/C6 Corvettes, Pontiac G8s, fifth-generation Camaros, and trucks/SUVs, and for good reason. They are relatively easy to install, deliver an excellent return on investment when it comes to horsepower, and have proven to be very durable. However, Corvette applications have underhood clearance problems, and an aftermarket or modified stock hood is typically required.
Based on the technology introduced on the C7 Corvette ZR1’s LT5 engine, Eaton-based 2650 (2.65L) compressors are the largest-displacement TVS-style superchargers available. The 2650’s rotors are larger in diameter than previous TVS rotors, which raises the overall height of the blower. That can present underhood clearance problems for some vehicles. The kit shown is from Harrop.
The large displacement of the 2.3L TVS compressor helps generate truly impressive performance. In the application seen here, a Harrop-supplied TVS blower was used on a 7.0L LS engine to make nearly 900 daily drivable horsepower on readily available pump gas. The engine was then stuffed into a Pontiac Solstice roadster by Thomson Automotive.
Edelbrock’s supercharger kits use Eaton’s four-rotor, 2.3L TVS compressor at their cores. Like the factory LSA and LS9 engines, the E-Force systems feature air-to-water intercooling systems with dual-brick-style heat exchangers mounted on top of the supercharger assembly. Design features of the E-Force system include a front-driven compressor and long, 12-inch intake runners that optimize low-RPM torque. For C6 Corvette owners, the advantage of the E-Force kit is that it mounts under the stock hood.
Rather than using the inter-meshing lobes of the Roots type, the Lysholm uses a pair of worm screw-type rotors that squeeze air together to generate boost. It also generates internal compression, meaning it develops pressure progressively as the air is continually squeezed by the screws on its way to the discharge hole. This can help build more low-end power and deliver more boost at lower RPM. The relative efficiency of twin-screw superchargers is greater than a conventional Roots type. They also enable generally higher boost levels than Roots or centrifugal superchargers, providing 20 pounds or more with some compressors.
Sweden-based Lysholm Technologies AB (a company that has undergone several corporate changes in recent years) is the name behind the technology, and it manufactures many sizes of twin-screw compressors, ranging from 1.2 to 3.3 liters in displacement. Rather than offering retail systems, the company licenses its product to other manufacturers, including OEM companies such as Ford, which used a Lysholm supercharger on the 2003–2006 GT sports car (through a licensing agreement with Eaton that essentially made them Eaton superchargers).
A Vortech supercharger system is installed on a fifth-generation Camaro SS.
In the performance aftermarket, Whipple Industries is just about the most recognizable name in twin-screw technology. Its Lysholm-type blowers derived from industrial air compressors were adapted to automotive use. For years, Whipple relied on the twin-screw compressors from the company currently known as Lysholm Technologies AB, but since 2005, it has used a twin-screw compressor of its own design. Whipple offers kits for Gen V Camaros, C6 Corvettes, LS-powered trucks, and the Chevrolet SS sedan.
In 2009, Vortech joined the twin-screw blower fray with the addition of a Lysholm-based supercharger of its own. Rather than manufacturing its own blowers, Vortech licensed the compressors from Lysholm Technologies AB and developed its own installation kits. Vortech offers 2.3- and 3.3-liter superchargers. Currently, the only dedicated twin-screw kit for LS engines from Vortech is for 5.3L truck engines. The company also offers “tuner” kits that can be adapted to a variety of LS engines, as long as a suitable manifold is available to match the ports on the cylinder heads.
Another player in the twin-screw market is Kenne Bell. At the time of publication, the company offered several twin-screw supercharger kits for the Gen V Camaro with compressors displacing 2.8, 3.6, 4.2, and 4.7 liters.
This Lysholm twin-screw supercharger system is installed on a fifth-generation Camaro SS.
The principle of the twin-screw design is a pair of screw-shaped rotors that intermesh much like the rotors of a Roots blower, but the rotors’ shapes create internal compression that helps boost low-end power. Whipple designed its own compressor in 2005. It features self-contained lubrication, a large bypass valve, and the capability of up to 30 pounds of boost. It is manufactured in a variety of sizes with many of them larger than the largest-displacement Eaton TVS compressor.
Vortech’s Lysholm-supplied twin-screw supercharger system for 5.3L LS-powered GM trucks includes an integral bypass valve within the supercharger housing. The kit also includes a charge-cooler/intake manifold assembly (with fuel rail mounts), higher-rate fuel injectors, a pump system for the intercooler, and a cold-air-style air intake system. Tuning calibration is provided via a DiabloSport Predator programmer. Similar systems are expected for a variety of other LS-powered vehicles.
Centrifugal Superchargers
Although engine-driven and not exhaust-driven, a centrifugal supercharger generates boost much like a turbocharger. It uses an impeller (similar to a turbine) that spins upward of 40,000 rpm to draw air into the compressor and blow pressurized air into the engine.
The impeller is the engine-driven part of the supercharger, as it is linked via a pulley and belt to the crankshaft. After the impeller draws air into the compressor head unit, it is squeezed and forced into the supercharger’s scroll (a chamber within the head unit that funnels the compressed-air charge out of a discharge tube and toward the engine’s throttle body). The scroll has a progressive shape that gets larger the farther it is from the center of the head unit. That design feature reduces airflow while simultaneously increasing the air charge’s pressure.
Air is compressed
