Significant power increases of 150 HP or more require engine modifications and tuning. Power increases above 250 HP generally significant engine rebuilding using racing parts. In some cases involving desired increases above 250 HP, the engine is replaced altogether; however such cases are generally geared toward dedicated racing applications. While FRANJO SPEED
will take on most any job a customer wants, the majority of customers will be looking for power adders in the 150 – 250 HP range since such increases can be achieved without sacrificing drivability and normal driving fuel economy. For increases of 150 – 250 HP, enthusiasts generally have 3 choices: add superchargers, turbo chargers or nitrous oxide kits.
Very simply, superchargers (SCs) and turbochargers (turbos) are “forced induction” systems in that they force more air into the engine, which, when combined with more fuel, creates a more powerful internal combustion, ultimately translating into more power at the wheels. Superchargers use rotors or impellers attached to a belt-driven shaft to force more air into the
engine. The advantage of a belt-driven SC is that the rate at which its rotors or impellers are turning matches the engine speed, and so power boost is instantaneous, always available and matches the engine’s demand. Turbos, on the other hand, are driven by exhaust gasses rather than mechanically by engine. Turbos utilize a shaft with two impellers—one located in the exhaust stream (usually piped into the exhaust system after the exhaust manifold/header), and the other one located in the intake air stream. While effective, turbo installations are more complex than superchargers and they tend to suffer from “lag” in that power boost isn’t available until impellers “spool up” as exhaust gasses build under acceleration.
The third power adder alternative is a Nitrous Oxide system. These systems make power by injecting Nitrous Oxide into the air inlet. When introduced into the combustion chamber, heat causes the Nitrous Oxide to breaks down into oxygen and nitrogen. The added oxygen, combined with more fuel, improves combustion and therefore power. The Nitrogen has the added benefit of cooling the intake air temperature, making the air denser, also improving combustion and power. These systems consist of a bottle of Nitrous Oxide (usually located in the trunk) with tubing routed to the intake system and some electrical controls. The system injects Nitrous Oxide into the intake only under wide open throttle (WOT) for a burst of added power.
FRANJO SPEED’s consultative approach helps the enthusiast decide which is best for him based on his goals and particular application.