After installing a new after-cat...
After installing a new after-cat exhaust and upgrading our Xterra's computer chip, our Dyno showed a gain of approximately 14 hp and a slight increase in torque, all at a cost of about $46 per horsepower.
Ever since we added an ARB Bully Bar to its nose and a TJM snorkel to its A-pillar last month, our Project Xterra has been turning heads anywhere we take it. Codgers stare, old ladies glare and guys cruising Fords and Chevys can't get enough. Clearly, no one's ever seen an Xterra quite like this one. Stopping at a red light, a guy in a Suburban gave us the old thumbs up and then joked, "Is that that new Chevy?" Nope, it's just the Four Wheeler Xterra.
Our X has been lifted and fit with a new set of shoes, JKS antiroll-bar disconnects, a Warn winch and IPF off-road rally lights to go along with its new height and wheels. We also installed RS 9000 shocks, a steering stabilizer and an idler-arm brace.
Now it's time to squeeze some extra power out of the X's systems. To begin, we visited our friends at Kilby Enterprises, where owner Brad Kilby helped us install a high-output 180-amp alternator from MG Industries. According to its manufacturer, the Mean Green alternator offers 300 percent more power than our stock unit. Then we went to Gibson Exhaust where we turned one of its after-cat systems for a naturally aspirated 3.3L Xterra into an after-cat for our supercharged version. It required some inventiveness on the part of our installer, but still the install took less than an hour and a half-standard time, according to Gibson.
Once we got our new exhaust on, we cruised down the highway to Jet Performance Chip in Huntington Beach, where we recalibrated the SUV's ECU, then slapped the Xterra onto a dyno. The dyno run proved that between the freer-flowing exhaust and the changes to the computer's codes, we'd coaxed an additional 14 horses out of the Xterra's engine. One downside to this: Because we've tinkered with the ignition system's advance curve, we now run 91-octane gas for maximum performance-all of Jet's tuning is designed and calibrated for 91-octane fuel.
Our upgrades took about 90 minutes per item. Nothing took five minutes.