Honda Civic HatchBack - Power Pages

The EngineIn our last Power Page installment for this Civic we discovered that the motor, despite being in its teenage years, was still more than willing to make more horsepower; baseline numbers checked in at 95.2 hp and torque readings came up with 81.5 lb-ft. After the installation of The Big Three (intake, exhaust, and header) the car was putting out a respectable 104.2 hp with a corresponding torque number of 92.3 lb-ft. The power and torque curves both rose throughout the entire rpm range and this translates into one thing: a faster car. Remember, horsepower gains don't amount to much if they're limited to that last 500 rpm right before you hit redline; the desired effect would be to have a smooth power curve that is, as a whole, relatively higher than the original baseline and subsequent graphs.

Performance ComponentsThis time around, we are trying a combination of both the "brute force" and "finesse" methods of adding power. Brute force additions require, basically, swapping out whole engine components to higher capacity, higher flowing, units-intake, exhaust, header, etc. The finesse method requires the advanced knowledge of a competent engine tuner that can precisely tune the new power-adders to extract the maximum amount of horsepower in the broadest range of power.

On the brute force side, we have the Landspeed high-flow catalytic converter. Many people don't realize that, in spite of changing out the intake, header, and exhaust systems to units that are larger in diameter (and therefore capable of flowing higher volumes and velocities of air) there still remains a weak link in the chain of events-the catalytic converter. Often we find ourselves constricting the airflow to a 1.50-in. or 1.75-in. diameter within the stock cat which, incidentally, usually also contains air catching vanes or "ledges" that slow down and restrict the air flow. For street-driven applications, Landspeed's highly polished stainless steel catalytic converter is the way to go. With an internal diameter that balks at the stock cat, the Landspeed unit is sure to keep the exhaust flow on the move.

With an internal combustion engine, adding more air necessitates adding more fuel to burn, and this is where the dynamic-duo known as the AEM fuel rail and fuel pressure regulator come in. With both of these parts, you can expect the fuel system to send higher volumes of fuel to equate your added air volume and, theoretically, help you add more power. The AEM fuel system components come in several colors to complement your engine bay and are precision CNC machined to ensure an exacting fit. And, since there is such a thing as too much fuel, the AEM regulator is continuously adjustable to allow fine tuning of your air/fuel stoichiometry.

The final and most prolific tuning element in this month's Power Page equation is the AEM adjustable cam gear. This gear allows you to adjust the point when your valves open and close (as dictated by your camshaft) in order to maximize the intake and exhaust flow in your combustion chamber. Using the easy-to-read degree markings and a reliable horsepower testing unit, you can adjust the timing of your camshaft and lock it in place to insure you have maximum power underfoot at all times. Plus, the availability of several finishes ensures that your underhood components are aesthetically pleasing.

Dyno TestingNow we go back to the Import Tuner Tech Center, where we re-dynoed at 103.1 hp and 92.1 lb-ft of torque after our initial runs. Bolting on the catalytic converter was a cinch, as it should have been, and we got to work laying down some dyno runs. With the restrictive catalytic converter out of the way and the new and improved Landspeed cat in place, we managed to shift the upper and midrange regions of the graph in the upwards direction to the tune of about 3-4 hp. This graph is a perfect example of why simply evaluating peak numbers isn't good enough to determine the effectiveness of a specific part. Both horsepower and torque didn't see an increase at the peak point, but there was a good power increase nearly everywhere else in the powerband. Obviously, the high-flow cat is flowing high. Next up to bat was the AEM fuel rail and fuel pressure regulator combination. Replacing these components in the engine bay took a little bit longer than the usual "bolt and go" formula, since we were working with pressurized fuel lines and small gaskets. After about an hour we checked for leaks and found none, so we made our way back on to the rollers. Using a fuel pressure gauge, we calibrated the AEM adjustable regulator to stock specs and began our tuning, steadily increasing fuel pressure in minor increments until power began to drop. We eventually found the adequate fuel pressure when peak horsepower went to 105.7 hp and torque maxed out at 94.6 lb-ft. Again, overlaying the graphs showed us an increase in power throughout the powerband, especially in the upper regions, and this reflected with the 1.5 peak power increase and 2.3 lb-ft peak torque gain.

The last step in our brute-finesse combination was to install the adjustable cam gear. Since this is a single cam motor, the installation was relatively simple and it was easy to deduce (from experience) that we would have to advance the cam timing to make more power. Fiddling around with the sprocket netted us a smoothing of the powerband, and wherever the power dipped was brought up to par. Again, torque and horsepower both showed beneficial increases by advancing the timing of the camshaft to open the valves earlier, a logical step from adding copious amounts of intake air. Peak numbers, for those that still want to know, clocked in with a 1.9 gain in horsepower and a gain of 3.4 lb-ft of torque.

ConclusionAs we even out the benefits of adding more power by giving the car a little bit of fine-tuning to go with it, we can see that the little Civic sohc engine still has room to breath. Those of you that are interested in getting more power out of your existing Civic (or looking to buy an inexpensive starter vehicle) should be convinced that the this car has been, and still is, a potent performer in the automotive upgrade arena. By pulling a Clint Eastwood and spending a few dollars more, we were able to beat up and fine tune our little rolling rollerskate to more respectable levels of power. And that, folks, is what it's all about.