2008 Honda Civic SI - Dyno 1: Baseline - Power Pages

Pros
Fujita's kit comes complete with everything needed for the install and then some. Fitment was perfect, replacement vacuum lines were cut to just the right lengths and the filter fits in the engine bay with room to spare. Initial throttle power levels jumped, as did power after the VTEC switch over point. The louder, deeper intake growl under wide-open throttle was a welcome improvement over stock, as was the tubing's bronze wrinkle-paint finish.

Cons
The new Civic's OE intake design is a complete maze compared to those of older years. we had to temporarily remove the battery, windshield fluid reservoir and several hard-to-reach clips just to pull out the airbox and upper tubing. The Civic's cramped engine bay requires short ram intake systems to position their filters toward the back of the engine bay near the header-taking in a warmerthan- desired supply of air; even worse, any cold air intake would have to position its filter element underneath the frame rail, possibly exposing it to water, dirt and other road contaminates.

Parts
Intake tube, filter element, silicone coupler, silicone tubing, clamps, all the necessary hardware, license plate frame, stickers, NOS beverage

Tools
Phillips and flat-head screwdrivers, 10mm deep socket wrench, extension, pliers

Installation Time
30 minutes

Notes
By this point, installation of the Fujita intake leveled out the powerband a little, eliminating the strange fall-off of power at the low and high extremes. Power production actually rose (to a point) over the course of several dyno pulls, just as it had after the addition of the Skunk2 exhaust-the ECu gradually adjusted to the increased airflow.

Dyno 4
Vibrant Performance SI Header With High Flow Cat
Peak HP 184.4 / Peak TQ 129.4

Horsepower Gain
* 2,000 to 3,500 hP range: -2.1 to 0
* 3,500 to 5,500 hP range: 0 to 2.1
* 5,500 to redline hP range: 0 to 9.2

Torque Gain
* 2,000 to 3,500 tQ range: -2.1 to 5.9
* 3,500 to 5,500 tQ range: -2.1 to 1.6
* 5,500 to redline tQ range: 0.1 to 6.9

Pros
Vibrant Performance adds a high-flow catalytic converter to their Race Header with this unit. Since the '06 and later OE Civic Si header has its catalyst welded-in, replacing the header means removing the cat as well. Most aftermarket manufacturers simply design headers around that fact-with no replacement cat. Vibrant offers one of the only solutions for Civic Si owners to modify their cars while maintaining some semblance of street legality. The Vibrant header/cat combo accommodates the OE O2 sensors, features longer, wider runners and full stainless steel construction. Oh, and it brought monster gains in top-end power.

Cons
Removal of the OE header set-up was a royal pain in the ass! Aside from that, nothing.

Parts
Header and cat combo

Tools
17-, 14-, 10- and 12mm sockets, swivel, wrench and extensions; breaker bar or impact wrench; 14mm open-end, 17mm brake line wrench or socket, pocket knife or razor blade, wD-40

Installation Time
One hour

Notes
Set aside plenty of time for installation. The heat shield and top row of bolts holding the header flanges onto the cylinder head have to be accessed from above the engine, meaning the windshield wipers, lower windshield "plastics" and metal gutter all have to be removed first. The lower row of flange-section bolts can be removed from below (with a swivel socked and no less than 2-feet of extension), but the section of piping housing the catalyst and connecting to the exhaust has to be removed first. Once you've detached the flange section from the head, six bolts holding the car's front cross-member to its unibody need to be loosened to give enough room for the flange section to be pulled out. Afterward, the aftermarket replacement can slide in its place-but only at a very particular angle. Then you get to do it all in reverse!

Conclusion
Testing to our '08 Civic Si reinforced the inescapable truth that increasing power in newer cars is becoming increasingly more difficult with simple bolt-on parts. The mechanical advantages of all the parts we installed were visually apparent, yet the power gains weren't as large as some we've seen on engines with far less potential than the K20. while every part we added made power, seeing the Ecu adjust to compensate for each change all but proved to us that more power could be made. Does this mean you shouldn't waste time modifying the newer platforms? No, it simply means there's more to be discovered through tuning. Look for a future installment of Power Pages, in which we'll be testing an engine management product that claims to offer as much power in one step as we've made here in three-proving the new Si isn't a platform to be overlooked.