Power Pages: Mitsubishi Eclipse

In the Eclipse session, our Diamond Star got a double injection of horsepower and torque with the addition of an intake, exhaust, and header, the three most common bolt-on power adders. Our final numbers were impressive, with horsepower at 117.2 hp and torque at 121.6 lb-ft. More importantly, the power and torque were present not only at the peak points, but almost consistently delivered throughout the powerband. Examining the previous power graphs with a magnifying glass and a fine-toothed comb showed increases as high as 10-12 hp at some points, especially in the lower rpm regions. This is especially helpful for all the drag and stoplight racers who want that extra push off the line, and even more helpful in a "daily-driving" situation, where rpm stay relatively low.

Performance Components
The last installment for the 420A motor saw the addition of basic performance bolt-ons--an intake system, an exhaust system, and a header. Our net gain was more evident in torque than peak horsepower, with torque output jumping from 112.9 lb-ft to 121.6 lb-ft. Peak horsepower went from 113.0 hp to 117.2 hp. While this doesn't sound like a whole hell of a lot, the true tale lies in overlaying the graphs. The entire powerband shifted up in this range with peak gains often higher than the maximum peak horsepower. See our previous issue for more on these tests.

This issue, we are testing how well the engine takes to fine-tuning as we add adjustable cam gears. The addition of the gears should "clean up" the power curves and extract more horsepower hidden within the engine and its components. Adjusting the camshaft timing parameters to match the performance components that are already installed boosts the motor's efficiency and helps to unleash more power and torque. Finally, we will add the mother lode of all bolt-on power adders--the nitrous oxide system--to see just how high we can fly.

Our adjustable cam gears come from AEM. The gears are machined from 6061 T-6 billet aluminum material for maximum strength. The markings and graphics are laser-etched and painted in white for easy visibility when tuning the vehicle. The gears are precision machined to match factory teeth; this eliminates premature wearing of the belts and the gears themselves. With the appropriate tuning instruments, the cam timing can be dialed in to open and close the valves at the exact times and for the exact duration needed to maximize the efficiency of the motor.

Since the number-one complaint of Eclipse RS owners is the lack of a turbocharger, we decided to test an alternate form of whip-ass--the throttle-in-a-bottle, 10 lb of laughing gas, nitrous oxide. We didn't want any to be able to say, "Don't worry about that car--it's a non-turbo model." Nitrous Express' universal single fogger kit is just the solution we were looking for. The kit comes complete with everything needed to make our Eclipse truly shine: bottle, jets, lines, solenoids, and the company's patented Shark nozzle, which atomizes the fuel and nitrous more efficiently. The bottle in the stage one EFI kit holds 10 lb of laughing gas, enough to get you through a day at the races or an evening of fun-filled excitement. A system power switch and full throttle switch are included to make sure the nitrous is on when you need it. Stainless steel braided lines and anodized fittings ensure the integrity of the nitrous system.

Before we start trying to make more power, however, we want to make sure that everything is running the way it's supposed to, especially after all the hard driving down between the original dyno session and the new one. So, a basic tune-up will be first on the list--changing the oil with Royal Purple's engine lubricant and making sure the spark plugs are fresh and can handle the increased demands of the nitrous system. For this task we chose NGK's BKR7E's plugs.

Dyno Testing
We trekked our way up to Dynamic Autosports in Irvine, Calif., after making a date with Eddie Kim, Dynamic's proprietor and Big Man On Campus. He set us up with some fresh oil and some new spark plugs and sent us over to Aries "DynoBoy" Dizon, tuner extraordinaire. We added some fresh Royal Purple motor oil and a set of NGK BKR7ES spark plugs, and then bolted the car to the dyno. Surprisingly, our horsepower and torque figures increased to 119.0 and 122.7, respectively. This is a good increase from our previous 117.2 hp and 121.6 lb-ft numbers. It just goes to show you a tuned-up motor is a happy motor, and a happy motor is a powerful motor. So, get your ass off the couch and give your car something to smile about.

Now back to the good stuff. The installation of the cam gears on the 420A motor requires quite a bit of effort, and time was not on our side because of the high demand on the Dynamic Autosports' dyno. Therefore, the cam gears and the nitrous kit were previously installed by Pann Auto Performance in San Diego, Calif., who did a bang-up job on installing the bolt-on goodies with precision craftsmanship. The sprockets were installed to zero degrees advance/retard, so this did not alter the baseline settings a bit. Dynamic's Mr. Dizon did alter the settings, and after a few hours of tuning and re-tuning on the Dynojet, he ended up with 126.0 hp and 127.9 lb-ft of torque.

Adjusting the camshaft timing resulted in a shift of the entire powerband from 2600 rpm to redline. The biggest horsepower increases began at 4000 rpm and gradually grew until redline, with the largest peaks seeing about 9 hp. Additionally, low end torque jumped up almost 6 lb-ft and then started to taper off towards the high end, with a 4 lb-ft increase still realized at the 7200 rpm redline. The end result: more usable horsepower throughout the entire range of engine's capacity.

The next thing on our list was the Nitrous Express single fogger kit. We could expect that when jetted for 50 hp, the kit would produce approximately 40 more hp at the wheels (with a 15 percent drivetrain loss figured in). The NX kit delivered, and the final horsepower on the bottle jumped to 163.0 hp, while torque registered a devastating 165.4 lb-ft. Again, examining the graphs and the spark plugs closely after the nitrous pulls revealed that the motor was in perfect health and ready for more. Larger jets were available for testing, but due to time constraints we didn't have the opportunity to put them in.

Conclusion
The 420A in the Mitsubishi Eclipse is a competent motor. Although not necessarily tuned for performance from the factory, the addition of basic bolt-on parts can help unleash the horsepower and torque in this 2.0L motivator. Exploiting the motor's strength, its relatively high torque numbers, seems to be the key to getting the Eclipse where it wants to go faster and quicker. So, if you drive of one of these machines, add some bolt-on goodies, stir in some laughing gas, and shake well for a delicious performance meal.