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 in the head unit when it leaves the impeller and is forced into the scroll. A venturi-like outlet, through which the air is forced, creates boost pressure, so the greater the impeller speed and the faster the air moves through the venturi, the higher the boost pressure.
A centrifugal supercharger is comparatively efficient, requiring relatively little engine power to drive, but its downside is the need for very high impeller speed to make horsepower-building boost. That’s why centrifugal blowers are known mostly as mid- and higher-range power adders; the impeller speed at lower RPM doesn’t make sufficient boost, and once the maximum impeller speed is achieved (usually around the peak horsepower mark), boost levels trail off at higher RPM.
A change to a smaller-diameter drive pulley can add a few extra pounds of boost, but matching a properly sized compressor head unit with the displacement and airflow capabilities of the engine is the key to sustaining power throughout the middle and upper ranges of the RPM band.
The two main players in the centrifugal supercharger business are Vortech Superchargers and ProCharger. Another centrifugal blower manufacturer is Rotrex, but currently, there were no direct applications for LS engines. The following is a closer look at the offerings from Vortech and ProCharger.
Vortech Superchargers
Vortech centrifugal superchargers have been mainstays of both the street and racing worlds. Typically, Vortech blowers are known for their relatively quiet performance and engine-oil-fed lubrication system (except for the V-3 compressor). Vortech has also been at the forefront of developing bolt-on kits, which are available for most popular LS-powered vehicles, including the fifth-generation Camaro. Several aftermarket companies, such as A&A Corvette, use Vortech compressors as the basis for tailored supercharger systems (see chapter 5 for details on installation).
Vortech offers a number of different compressors designed for a wide variety of performance requirements. They’re also subdivided among “trim” types: X trim, F trim, SCi trim, etc. Here’s a quick rundown on them.
V-1 Series: A high-performance compressor with high-speed ball bearings that makes it compatible for high-boost, cog-belt racing applications. Depending on the trim, a V-1 is capable of up to 26 pounds of boost and 1,200 cfm of airflow.
V-2 Series: Lower maximum boost (17 to 22 pounds, depending on the trim) and slightly lower maximum airflow than the V-1, but designed as a direct replacement. V-2 SQ trim is known for exceptionally quiet operation.
V-3 Series: The only internally lubricated compressor in Vortech’s portfolio. A V-3 compressor fills the mounting brackets for V-1, V-2, V-4, V-5, and V-7 compressors. Maximum boost and airflow is similar to V-2 compressor trims.
V-4 Series: A racing-intended compressor that Vortech claims is twice as efficient as a Roots blower at 12 pounds of boost. Depending on the trim, a V-4 can produce up to 32 pounds of boost and flow 2,000 cfm.
V-5 Series: Designed for smaller-displacement engines, typically 4- and 6-cylinders, the V-5 is not well-suited to the airflow capabilities of LS V-8 engines.
Vortech centrifugal superchargers typically make 6 to 8 pounds of boost in most bolt-on kits, but a range of higher-performing, racing-oriented compressors can supply more than 30 pounds of boost. Most of Vortech’s compressors are interchangeable with the company’s brackets, allowing you to swap compressors to better suit your engine combination. (See chapter 5 for installation details on a Vortech-based bolt-on system.)
V-7 Series: A high-flow, racing-intended compressor designed for modified engines built to accommodate high boost levels. Depending on the trim, a V-7 can flow more than 1,400 cfm and generate 30 pounds of boost.
V-9 Series: This more compact compressor is designed for engine compartments with little room, such as the fourth-generation F-Bodies. They’re also designed for smaller-displacement V-8s (smaller than 400 ci). Maximum boost is about 14 pounds and maximum airflow is 750 cfm.
V-30 Series: Replacing the V-20 series, the V-30 is designed for racing applications and can push enough air to support 1,000 hp with about 35 pounds of boost.
An excellent reference chart of Vortech’s various compressors, trims, and boost/airflow capacities is available at vortechsuperchargers.com.
ProCharger
Unlike Vortech blowers, most ProCharger compressors have a self-contained lubrication system, meaning there’s no need to tap the oil pan for the oil feed source. Some of the ProCharger compressors are relatively loud, especially at idle, but their street-based blowers have become admirably quiet in recent years. The company offers bolt-on kits for most LS-powered production models, including C5 and C6 Corvettes, fourth-generation F-Bodies, Gen V Camaros, Pontiac GTOs and G8s, and more.
Like Vortech, there are numerous compressors in the ProCharger portfolio with several designed specifically for racing applications. In fact, ProCharger offers the largest centrifugal superchargers, with some capable (including the colossal F-3X-143 compressor) of producing up to 60 pounds of boost and flowing 4,500 cfm. And with less-complex tubing routing than high-boost turbo systems, ProCharger offers a viable alternative for the street and drag strip.
| ProCharger Compressor Comparison Chart | ||
| Compressor | Maximum Airflow (cfm) | Maximum Boost |
| P600B | 1,200 | 24 |
| P-1SC | 1,200 | 30 |
| P-1SC-1 | 1,200 | 32 |
| P-1SC-2 | 1,200 | 30 |
| D-1 | 1,400 | 32 |
| D-1SC | 1,400 | 32 |
| F-1 | 1,525 | 38 |
| F-1A | 1,650 | 38 |
| F-1C | 1,850 | 38 |
| D-1R | 2,000 | 32 |
| F-1R | 2,000 | 38 |
| F-2M | 2,250 | 40 |
| F-2 | 2,700 | 38 |
| F-2R | 2,750 | 38 |
| F-3A-117 |
|