Brian enjoys how power still comes in early and now climbs all the way to redline. Considering a stock ’08 STI produces approximately 250 horsepower on the same dyno, Brian’s Subaru now produces nearly 100 horsepower more than when he drove it off the dealer lot. Strapped down to a Dynojet AWD dynamometer, the STI produced 346 horsepower and 320 lb-ft torque at the wheels. The technicians manipulated the fuel and ignition tables of the HKS F-CON V Pro and set the boost to 20 psi on the HKS EVC boost controller. The STI was brought to SP Engineering to dial in the installed boost, fuel and ignition components. This ensures every ignition cycle burns the combustion mixture properly and no fuel or power is lost to misfires. An HKS Twin Power DLI-II ignition amplifier increases the voltage supply to the plugs, allowing spark initiation under high-boost conditions. Once the air and fuel is compressed inside the combustion chamber, HKS M40IL spark plugs ignite the air/fuel mixture. When the charge air reaches the intake ports, Power Enterprise 850 cc/min injectors atomize premium pump gas into the airstream. Rejecting this heat increases the density of the charge air allowing for better power production and also reduces the chance of engine- destroying detonation. To combat this, an HKS R-type front-mount intercooler mounted inline between the compressor outlet and throttle body rejects the charge air heat. As the intake air is pressurized at the compressor, it’s temperature increases. While some choose to leave the race applications compressor inlet exposed, lack of intake filtration wouldn’t be an option for daily driving. On the cool side, ambient air is filtered by an HKS Racing Suction Reloaded kit before being drawn into the compressor.

An HKS GT II 60mm wastegate regulates the exhaust gasses flowing through the turbine, helping to control boost.

Hks turbo