Car: Honda Civic Si
Product: Vortech V5 Supercharger Kit
Boost: 10 psi
When it comes to boost, old-school thinking says superchargers are known for their low-end enhancement, while turbos get the glory at the high-end.
When talking about GMC blowers and traditional old-school "Roots" designs, this thinking is more or less correct; but it's still old school. One of the advantages of a centrifugal supercharger is its impeller design and the fact that it operates in relationship to engine speed. These factors make the centrifugal supercharger "act" like a turbo. Combine these factors and match the centrifugal unit to a high-revving engine and you have a street screamer. Vortech Engineering saw the light and matched its V5 blower to a Honda VTEC engine-not just any Honda VTEC, but the 1.6-liter Civic Si.
When Vortech developed its kit, it selected the V5 for its compact size, but there were some other technological advancements that made it the right part for the job. The compressor wheel is a G-trim unit and is capable of supporting up to 575 hp. Through the years, oiling has long been a challenge for blower manufacturers who have tried internally oiled units, no-oil units via ceramic materials and externally oiled units that use the engine oil system for lubrication.
The latter is the best and is currently the industry standard. Vortech has devised a clever way to increase the lubrication in its system. An oil drain-back valve siphons a nominal amount of boost pressure and uses the air to atomize the oil prior to entering the blower case. The oily mist created ensures all surfaces are properly lubricated.
Again, in much the same fashion as a turbo, the V5 kit includes a bypass valve. Like in a turbo system, the Maxflow bypass guards against compressor surge when the throttle is suddenly closed. As the driver jumps off the gas pedal, the throttle plate closes and boost pressure hits the plate and backs up until it re-enters the compressor where it tries to stop the compressor wheel from turning by pressuring it to spin in the opposite direction. This condition can put a strain on the unit's bearings. The bypass valve senses the pressure build-up and depressurizes the intake system by venting the boost into the atmosphere or into the intake tract before the compressor.
Intercooling is a chore often associated with turbos and one that many supercharger companies used to illustrate the complexity and cost of turbos vs. superchargers.
The power potential of intercoolers and the complexity of today's ECUs have led to a new line of thinking. Vortech incorporated its Power Cooler liquid-to-air aftercooler into the Civic Si. The Power Cooler features a self-contained cooling system, which means ice can be added or an alcohol/water combination can be run when extra cooling is essential.
The fuel system consists of a high-flow, in-line fuel pump, a Vortech FMU, a Vortech fuel pressure optimizer and upgraded fuel rail. The system uses the FMU to increase fuel pressure in accordance with a rise in boost pressure utilizing the stock injectors.
Off To The Cell
Our test vehicle was also outfitted with the typical bolt-ons-a Comptech 4-2-1 header, APEXi N1 exhaust and K&N intake. Boost checked in at 10 psi.
A stock Si from previous testing laid down 142 hp and 102 lb-ft of torque; what would the Vortech-boosted Si pump out? The testing produced one of the more aggressive power curves we have seen. The V5 was not shy about pumping out the boost as only the 7900 rpm rev-limit stopped the party. At the 7900 rpm cut-off, the blower provided its biggest increase, a whopping 132.6 hp and 88 lb-ft of torque. What floored us was the steepness of the curve and how the B16 unleashed the power and torque after the VTEC cam lobes were put into effect.
About the only critical aspect of the Vortech blower package is the installation, which includes a driveshaft to connect the blower to the drive pulley. This may be complicated contrasted to an Eaton kit, which can have the manifold and blower cast in one piece. But remember: You only have to install it once and there are 272 raging ponies waiting at the end of the rainbow.
1999 Honda Civic Si<
Vortech V5 supercharger
Liquid-to-air Vortech Power cooler
Upgraded in-line pump, ortech FMU, Vortech rail, stock injectors
Stock w/Crane coil
Comptech header, APEXi N1 cat-back exhaust
Pulley, 10 ps