Superchargers Centrifugal Blowers - Suck,Squish,Bang,Blow

With a Roots blower, the supercharger assembly is usually cast into a custom intake manifold, making it difficult to package the intercooler. We've witnessed a Vortech supercharged and intercooled Honda B16A make 277-wheel hp and 175 lb-ft of torque at about 8 psi of boost, albeit over an extremely small rev range. With headers, a cold-air intake and a cat-back exhaust, even bigger gains can be expected.

One of the other main reasons for this kit's impressive peak power is the higher compressor efficiency. Compressor efficiency is a measure of discharge air temperature and power drain on the crankshaft. The Vortech V5 supercharger used in the Si kit has a 73-percent peak efficiency over a broad range.

Who offers whatVortech offers kits for the Civic, Prelude, Integra, S2000, 350Z, G35, Focus and all the Cavalier variants. Some Vortech kits offer optional water-to-air or air-to-air intercooling

Stillen has a kit using the Vortech supercharger for the VQ30-powered Nissan Maximas. This kit bumps the Maxima up to about 270-wheel hp. All have CARB approval for 50-state street legality. Fuel management for most applications is handled by a high-volume fuel pump and a boost-dependent fuel pressure regulator. Some of the kits for newer, returnless-fuel system cars use a piggyback fuel and ignition management system.

Powerdyne is currently producing a centrifugal blower kit for the D16-powered Honda Civic. A Powerdyne supercharger is very similar to the Vortech except the step-up drive is achieved via a belt instead of gears. The belt provides quieter operation than the gear drive in Vortech superchargers, which have a distinctive whine. Powerdyne claims an increase of about 80 hp to the wheels at 8 psi with its Civic kit.

ProCharger has kits for the 350Z, G35, FX35, Civic Si and Integra. One major advantage to the ProCharger kits is they come available with large front-mount air-to-air intercoolers that allow more boost and reduced risk of detonation. ProChargers make more power than other blowers on the same engine for this reason.

ProCharger's compressor has CNC-machined blades, many of which are radial in configuration. The compressor housings don't have much of a diffuser. These details were overlooked in very early centrifugal compressor designs. Engineers have learned much about compressor design since the '50s-thinner blades, curved vanes and proper diffusers would improve the ProCharger blower's efficiency. Even so, we can't argue with Procharger's impressive power gains.

Comptech also offers a Paxton centrifugal blower kit for the S2000. The Paxton is a centrifugal supercharger like the Vortech. Although Paxton does not make any efficiency claims for its supercharger, the S2000 kit makes an impressive 340 hp on Honda's S2000. This kit is CARB approved, a tremendous advantage if you want hassle-free registration in states that have a smog check.

HKS recently introduced the Rotrex centrifugal supercharger for the Nissan 350Z and Infiniti G35. Featuring high-quality components and an exceptionally clean installation, the HKS system looks almost like an O.E. application.

The Rotrex supercharger in this kit has some unique features. Instead of the usual gear or belt-driven step-up transmission, the Rotrex blower uses fixed traction planetary rollers to step up the speed to drive the compressor wheel. Traction drive is more efficient and soaks up less power than the typical gear or belt drives used by other superchargers.

The traction drive uses technology from Nissan's toroidal-drive CVT transmissions and requires a special oil to transfer drive torque between the rollers, which are also much quieter than gear drives and belts. The HKS kit features a piggyback fuel controller operating two 525 cc/min injectors for additional fuel enrichment and has a pending CARB E.O. for 50-state legality.

Adding up the power modsSupercharged engines respond to peripheral mods like headers, exhausts and low-restriction air intakes, often to a higher degree than naturally aspirated engines. A supercharged engine will like larger header primary tubes and collectors and need a bigger diameter exhaust than a naturally aspirated engine.

Supercharged engines also respond to high-performance camshafts of nearly the same spec as a naturally aspirated motor. Adjustable cam gears will come in handy here because a supercharged engine will typically like a little less overlap to prevent boost pressure from blowing out the exhaust port. The engine will also respond to head porting and other flow-improvement strategies.

Supercharging is usually a more reliable way to make power than through stressful engine-speed increases experienced in naturally aspirated engines. Increasing cylinder pressure with forced induction at lower rpm puts a compressive stress on the rods and crank. However, high rpm puts a tensile stress on the reciprocating components much greater than the compressive load a supercharger adds.

This bit of physics allows superchargers to obtain impressive results with greater reliability and lower cost than high-horsepower, naturally aspirated engines. Of course, this assumes detonation is avoided and the car has sufficient cooling capacity for its intended use.

In short, if you are not a racer looking to make the ultimate power and are trying to get a good tractable gain from your streetcar, then a supercharger could be the answer. Roots blowers provide immediate power that remains proportional throughout the powerband. Centrifugal blowers make better peak power that is achieved gradually in relative proportion to increasing engine speed.

Another consideration is that supercharger kits are usually made by big, reputable companies and are usually very complete. They are perhaps the biggest single power adder that you can bolt on in a weekend, and they are quite often the most powerful smog-legal modifications available.