After our bolt-on basics from our last article we wanted to eliminate errors caused on our own part by uploading a tune not optimized for our car. We called in the big guns at Church's Automotive Testing in Wilmington, CA. For a baseline we uploaded a stock, factory tune on our car with only the CT-Engineering intake and exhaust adding additional power. Our Si put down 210.8 hp and 158 tq on their Dynapack dyno vs. where we left off at 167hp 118 tq on Technosquare's Superflow AutoDyn 30 chassis dyno. As we did previously we also uploaded one of the base MAF tunes Hondata supplies for the AEM short runner intake. As before the car achieved the same hp but with much more power in the mid-range between 5,000-6,500 RPM.
Now the fun begins; a speed density map is used for reliability and repeatability and for tuning the high camshaft, (VTEC) is locked in at 3,000 RPM's. Tuning adjustments were done in this order:
- Low and High speed cam Fuel tables with cam angle
- Low and High speed cam Ignition tables
- VTEC setpoint
During this process we did dozens of pulls on the dyno justifying Church's recommendation of coming prepared with at least a quarter of a tank of fuel in the car. At the end of our session the results were nothing short of astonishing. Our tuned car made 4.2 hp and 3.5 tq peak power over stock but more impressive is all the power in the rev range. We saw a nice big jump in torque of about 7 tq, which every Honda needs, starting at 3,500 RPM's all the way through 6,000 RPM. There's a huge jump in torque starting at 5,000 RPM and 19 lb/ft from 5,800-6,200 rpms. The horsepower curve is nice and progressive and with all these power gains, we will not miss the VTEC kick.