2008 Honda Civic Si Pros: The latest Civic Si is powered by Honda's K20Z3, a motor nearly identical to the 200hp K20Z1 and K20A2 of the stateside RSX Type S and Euro-spec Civic Type R. The 'Z3's 11.0:1 compression bottomend and high-flowing head give it a fat, juicy 197hp powerband right from the factory, making the '06-and newer-Si an efficient, powerful commuter in stock trim, and a genuine force to be reckoned with when modified
Notes: After fitting our Si with an intake, header/high-flow cat combo, and after-cat exhaust for the May issue's Power Pages, we were left wanting more power. The 12 top-end ponies and the nearly 20 lb-ft of mid-range torque we picked up made a noticeable difference in the Civics' performance, but based on what some tuners were producing from the K with just a little work, we felt confident there was more power to be made, without getting too crazy.
Dyno 1: Baseline
2008 Honda Civic Si: Part Two Peak HP: 184.3 / Peak TQ: 129.8
Hondata ECU Reflash Pros: Installation is a cinch, turnaround time was fast, and the reflash delivered what it promised-a huge jump in mid-range power and torque; as much as 27 whp and 21 lb-ft of torque! Not to mention it completely flies under the cop radar and can be reflashed back to stock if need be.
Cons: The fact that there is turnaround time at all...but that's just because we're impatient.
Parts: Besides stock ECU, none
Notes As we pointed out in our previous installment of Power Pages with the Si, ECU tuning is absolutely critical in maximizing the benefits of certain upgrades done to newer, OBD 2 cars. The secret to Hondata's reflash lies in slight cam and ignition timing changes, leaner air/fuel ratios, and in their creation of a "VTEC window" which allows VTEC to engage at the most efficient time for a given throttle position between 4,500 rpm and 5,800 rpm-right where the K20Z3's stock tune lacks power.
Horsepower Gain * 2,500 to 3,500 HP range: -1.5 to 2 * 3,500 to 5,500 HP range: -6 to 27 * 5,500 to redline HP range: 1 to 22
Torque Gain * 2,000 to 3,500 TQ range: -2 to 2 * 3,500 to 5,500 TQ range: -6 to 19.1
Pulstar Pulse Plugs Pros: Changing spark plugs for more power? Yeah, that's our kind of mod! Installation took 10 minutes (because we're slow), and power gains were realized across the board, most noticeably in the top end.
Notes: We have to admit, we were a little skeptical about these things when we first saw them-another spark plug gimmick promising to make power? Please...but, when we actually read up on how they work, and saw that some reputable tuners were making power with them, we had to try. The consistent, across-the-board power gains the plugs made were a result of improved combustion, meaning not only more power, but better fuel efficiency too; a win-win for the street car. And considering the efficiency of the K-series' ignition system to begin with, we'd expect even bigger gains from installing them in older, larger engines
Dyno 3: Pulstar Pulse Plugs * 5,500 to redline TQ range: 1 to 21
Peak HP: 188.2 Peak TQ: 140.9
Horsepower Gain * 2,500 to 3,500 HP range: 0.9 to 1.1 * 3,500 to 5,500 HP range: 0 to 1 * 5,500 to redline HP range: 3.1 to 2.8
Torque Gain * 2,500 to 3,500 TQ range: -0.7 to 1.1 * 3,500 to 5,500 TQ range: 0 to 1.3 * 5,500 to redline TQ range: 0.5 to 3
NonStopTuning (NST) Lightweight Pulley Set Pros: Reducing rotational mass is always a reliable way to gain a few ponies on nearly any engine. NST's lightweight pulleys saved 4.2 pounds compared to the OEM ones, and do not under drive the alternator-meaning no dead batteries or dimming lights from an under-active alternator. The NST pulleys are CNC-machined from 6061 T6 aluminum billets, balanced to tighter-than-OE tolerances, and available in anodized red or black finishes.
Notes One of the great debates raging on inside Internet forums and debated over bench racing bouts, is whether or not lightened pulleys can harm an engine. The theory goes that lightweight pulleys aren't balanced to specific engines' harmonics the way their OEM counterparts are, and using them can increase torsional vibration that causes premature bearing failure. But, Honda K-series engines are balanced internally, and do not use balanced pulleys from the factory. And today's newer engines are constructed with tighter tolerances than those that were around back when this rumor got started. Bottom line is: If your engine has been properly maintained, using high-quality, balanced, lightweight pulleys like NST's will not harm it
Horsepower Gain * 2,000 to 3,500 HP range: 0.6 to 2.1 * 3,500 to 5,500 HP range: 0.7 to 2.9 * 5,500 to redline HP range: 2.1 to 4.5
Torque Gain * 2,000 to 3,500 TQ range: 0.7 to 3.1 * 3,500 to 5,500 TQ range: 1 to 2.6 * 5,500 to redline TQ range: 2.6 to 6.1
Conclusion After two installments of Power Pages and the addition of six basic bolt-on parts, our Civic Si has become a rolling billboard for the ways in which aftermarket modification can improve upon OE engineering. Bolt-on aspiration parts added in the previous installment allowed our Si's K20Z3 to breathe easier, increasing efficiency and making more power, while maintaining street legality. Hondata's ECU reflash optimized those power adders, along with Honda's own VTEC system, to eliminate the serious mid-range power lag K-series engines suffer from the factory. Adding Pulstar Pulse Plugs maximized the process of combustion already present in our K20, while even more free power was found by replacing the K20's heavy cast pulleys with lightweight billet aluminum NST replacements. Also impressive is that as power grew, demand for additional fuel didn't. Modifications completed to this point only served to increase our K20Z3's efficiency-meaning we'll see increased reliability and fuel efficiency from our new Si, alongside more power. ...As long as we can keep from driving it with a lead foot!