Power Pages: Honda Civic Si

The Engine
The Honda D16Y engine--it's the little engine that seems to have started it all. When this motor was introduced in the Civic/CRX line-up, the little Japanese econoboxes were suddenly praised for having a sporty nature, signaling the end of the "economical = boring" equation that occupied the minds of consumers at that time. With the engine pushing a factory rated 108 hp at 6000 rpm, the engine doesn't sound too impressive now, but relative to the cars available at the start of that decade it was good enough. Coupled with the car's suspension technology and relative cost of ownership, the Civic became a highly desirable vehicle to own.

Even years after the engine was introduced, several manifestations of the motor proved their worth, including the proprietary sohc VTEC model, but the non-VTEC 1.6L engine managed to maintain its general integrity. On the number-crunching side of things, the D16 sported a 75 mm bore with a 90mm stroke, putting the final displacement at 1590cc. The 108 hp teamed up with the 100 lb-ft torque (available at 5000 rpm) and still managed to produce an efficient 28 miles per gallon (32 mpg on the freeway). Now that we have a cherry-condition Civic Si on our hands, we're going to see just how high we can make those power and torque numbers go.

Performance Components
Some of us like to race up the performance ladder, skipping steps here and there. Others, perhaps limited by budget constraints, like to take one step at a time, reaping the rewards of each part added and enjoying the satisfaction of completing a job well done. Since this generation of Civics is still a popular platform to build upon, in spite of their 14-year existence, we are taking the road most likely traveled by the beginning tuner--one step at a time.

Our first step would be to swap out the factory intake system. Chances are, the stock air filter has been replaced a few times, but even this maintenance will never net the power gain of replacing the intake system with an AEM Cold-Air unit. We don't need to let you know all the benefits of the AEM CAI--chances are, you've probably heard it all before. So, our main focus here is to upgrade the factory system with a sportier, more efficient power-adder that adds, as a side benefit, that 1.6L intake sound that can almost be described as a "throaty growl."

Our exhaust system comes to us courtesy of A'PEXi and is of the WS variety, A'PEXi's new flagship exhaust system for the performance oriented street-driven consumer. The WS is constructed of the industry standard SUS T304 stainless steel and is engineered into oval design muffler. The muffler is packed with composite sound dampening cubes placed in an optimal flow configuration that keeps the World Sport system true to its name--sporty and legal in most parts of the world. The large exhaust tip lets people on the street know that you mean business and it's highly polished for a show-quality appearance.

Powercore header from Landspeed Racing is a header that is well known to us here at the Tuner offices. In a previous Power Page, this header made an outstanding amount of power on a B-Series Honda motor. Now, with applications for D-Series Civics and many more to come in the future, this header is sure to start making even more waves in the import performance industry. The header is of a one-piece four-into-one configuration. This allows for an equal amount of length among the runners and a maximum flow rate at the collector/flange area. The header is constructed of stainless steel and is highly polished to a mirror finish.

Dyno Testing
We strapped our almost-teenaged Civic to the Dynojet at the Import Tuner Tech Center and laid down a few baseline runs. Surprisingly, the car made 95.2 hp and 81.5 lb-ft of torque. This came as a shock to us because of the car's relative old age, but it was a pleasant shock, nonetheless. At least we know that this motor is a keeper.

The first step we took was with the AEM Cold Air Intake. As you can see, the factory airbox is quite restrictive. Even though Honda had good sense enough to run a plastic venting system to obtain fresh air for the intake, it could never seemingly run as good as with a direct blast of cold air like the AEM intake provides. Indeed, our suspicions were true as the easy installation of the CAI bumped our numbers up to 97.9 hp with 89.8 lb-ft of torque. The power and torque graphs shifted up considerably, showing considerable gains in the midrange area, right where it's needed the most.

The next step was to add the A'PEX WS exhaust. Replacing the factory exhaust was a cinch thanks to the excellent engineering design of the A'PEX team. Within minutes, the car was ready to turn the rollers of the dyno again. If you follow the Power Pages religiously, you might be able to tell that we place more emphasis on where and how the power comes in, and not so much on how high the peak number turns out to be. When it comes to adding power, it just doesn't make any sense to have a sharp peak in the upper regions of the powerband while the rest of the power stays relatively the same as before the installation. It's this "power shift" that makes your car faster and, effectively, feel stronger. Looking at the graphs for the WS exhaust, you can see that they were shifted upwards slightly and in an almost uniform distribution. This means that the little Civic now has more power throughout the powerband, in spite of the slight drop at the peak point. Torque was also raised in the same general fashion.

The final step was to add the Landspeed header. We expected wonders from this thing, and it didn't disappoint us. The power curve shifted up to 104.2 hp, while torque was equally compelled to join in on the fun, registering a 1.1 gain at some points. Final torque is an impressive 92.3 lb-ft.

Conclusion
As the import performance world grows by leaps and bounds, it's very easy to get caught up in trying to find the newest, latest, thing that no one else in the world has. Doing so will only cause you to overlook the potential of some proven performers; this is exactly the case with this Civic. Even though its been on the streets for over a decade, it was still able to make power, and not just more power than stock form, but enough to keep it in contention with some of the newer (and therefore more expensive) vehicles on the market today. It just goes to show you--you can teach an old dog new tricks. Keep your eyes posted and see just how many new tricks we can turn in upcoming Civic Power Pages.