There are two approaches to making big power; slowly adding parts over time or stepping up and transforming the engine in one fell swoop. If you want a big power jump fast, the three best methods available are turbo kits, supercharger systems or nitrous-oxide injection setups.

The SEMA Show is the stage where many manufacturers prefer to debut their latest and greatest kits. It is also a chance to read the tea leaves and get a feel for which cars will be the hottest tuning commodities in the coming months. The emerging super stars for forced-induction conversion fanatics at the 2007 SEMA show were the Dodge Charger, Ford Mustang, Chevy Corvette, Nissan 350Z and all manner of Scion—xB, xD and tC.

Turbocharging

An internal combustion engine makes power by burning fuel. The more fuel it burns, the more power it will make. However there must be ample air on hand to burn the combustion charge at the proper air/fuel ratio. Forced induction pressurizes the air, forcing more air molecules into a given volume of air, so more fuel can be added at combustion resulting in more power.

A turbocharger is an air compressor driven by exhaust gases. A big part of its efficiency is that it recycles or harnesses exhaust gases that are on their way out of the system anyway. The exhaust spins a wheel on a common shaft with the compressor wheel, which ingests air at the inlet, compresses it and blows it out the turbo nozzle and into the intake stream.

The typical turbo kit from companies like Turbonetics, GReddy Performance Products, HKS, RevHard, Cartech or HP Performance consists of an exhaust manifold with a turbo mounting flange, a turbocharger, an exhaust elbow/downpipe, air filter assembly, piping and hose connectors. Other items that may be standard or optional include an intercooler, blow-off valve, external wastegate, fuel system upgrades, ignition system upgrades and engine management electronics.

Supercharging

Like turbocharging, supercharging is a forced-induction setup that pumps more air into the engine. There are two types of superchargers: centrifugal and roots/twin-screw. The compressor section of a centrifugal blower resembles a turbo circular construction. A roots/twin-screw “blower” looks like a box with a tapered snout that secures the pulley. Inside the case are two screws that interlace as they spin, thereby compressing the air.

The biggest difference between a turbo and a supercharger is the drive system. Where turbos use exhaust pulses, a supercharger uses a belt driven off an engine pulley to spin the compressor assembly. Compared to a turbo, the advantage is less delay (or “lag”), while waiting for boost pressure to build. This is especially true of positive displacement units from the likes of Eaton, Whipple, Kenne Bell, TRD or Jackson Racing.

The typical centrifugal supercharger kit from companies like Vortech, ProCharger, Paxton or Powerdyne includes the blower, mounting bracketry, a new accessory belt, air filtration and intake piping. Other items that may be standard or optional include an intercooler, belt tensioner, fuel system upgrades, ignition system upgrades and engine management electronics.

Nitrous Oxide Injection

Nitrous setups have been called chemical superchargers, because they increase the amount of air in the combustion chamber by injecting nitrous-oxide, which is 36 percent oxygen by volume (compared to the atmosphere at 21 percent). There are two types of kits: dry manifold and wet manifold. A dry manifold system injects only nitrous oxide. Fuel enrichment is handled by the stock fuel-injection system, sometimes via an adjustable fuel pressure regulator. A wet system injects both nitrous and additional fuel.

A typical nitrous kit consists of a nitrous bottle, tubing, nozzles, flow jets, solenoids, an activation device, switches and miscellaneous wiring and fittings. Other items that may be standard or optional include gauges, bottle warmer, cooler spark plugs, remote valve opener and fuel system upgrades.