The 04 STI tested was equipped with a turbo-back exhaust system, catalytic converter, but was otherwise stock. Tuning started on the road since there are so many variables when tuning stand-alone engine management that just can’t be made while on a dyno alone. Often maps are made on the dyno and then de-tuned or altered to compensate for the difference in load and driving habits that are encounter while driving in the real world. After all a dyno is only a tuning aid but we wanted to get a feel for how exactly this map would look when placed on a dyno after tuning in the real world.
Significant gains in power and reliability were made with the Element Hydra STI. Using 93 octane pump fuel peak torque was 302.0 ft/lbs and peak power was 294.0 whp from 5500 – 5750 rpm.
Proper tuning of the AVCS system results in a very nice powerband with 300 ft/lbs of torque at 3600 rpm which is held to within 8 ft/lbs to 4600 rpm. The dip is where it was a little rich on the dyno (10.5:1 AFR) where there just wasn’t enough air flow to the intercooler. The whole run was a bit richer than we normally see in the real world with most of the map at 10.7-11:1 AFR and ignition advance a maximum of 22-23 degrees. The richest AFR was 10.5:1, at peak power AFR is 10.8:1, and at redline the AFR was 11.4:1.
Unlike stock STIs equipped with an exhaust system, boost creep was not an issue while using the Hydra EMS. Peak boost was about 17 psi, and then dropped to 13 psi by redline. The biggest limitation to power and reliability are the OEM injectors which ran static after 5500 rpm. A loss of reliable fuel control was the result so careful tuning of the ignition timing curve was required to prevent detonation. Larger injectors should be one the first upgrades to your STI.
Element Tuning Hydra STI ECM with Element STI Tuned Map
Turbo-Back Exhaust Sytem with Catalytic Converter
Tuning was performed using the aid of AutoTune which really helps in the tuning process by quickly adjusting the AFR based on a Target AFR Table. For more information on our performance computers and products please visit our products page. We’ll head back to the dyno for another test using 800 cc injectors.