Click for Coverage
Due to the EU’s Global Data Protection Regulation, our website is currently unavailable to visitors from most European countries. We apologize for this inconvenience and encourage you to visit for the latest on new cars, car reviews and news, concept cars and auto show coverage, awards and much more.MOTORTREND.COM
  • JP Magazine
  • Dirt Sports + Off-Road
  • 4-Wheel & Off-Road
  • Four Wheeler

2007 Jeep JK Wrangler Engine Upgrades - Power Player

Posted in Project Vehicles on July 1, 2008
Share this
The first thing we did was strap Project 'Con Artist down to the dyno and get our baseline run of a brutal 135 rear-wheel horsepower and 165 lb-ft of torque.

We were one of the first to tell you how barely adequate the Jeep 3.8L OHV V-6 is in the new Wrangler JK, especially in the Unlimited. Then we had to go and throw on bumpers, a winch, a suspension, wheels, and tires, and now we might as well cede on ramp-merging contests to, well, just about anything else. Was that a Vespa that went by? With one of the heaviest configurations offered (hardtop, Unlimited), the 'Con Artist was struggling to keep us up to speed after the 35s and the lift. Even with a drop to 4.88:1 gears, our JK still wasn't happy maintaining speed on highway grades as steeper climbs required dropping down to Third gear just to keep up with traffic. With power increases on the brain, we gave AEM and JBA Performance Exhaust a call to see if we could procure some parts that would not only help out our Jeep to offset some of its feelings of heft, but also to give it a little heartier exhaust note. We brought our Jeep down to JBA's Performance Center facility in San Diego, California, for the installs and dyno runs.

PhotosView Slideshow
The JBA muffler not only offers a fashionable polished tip, but the smaller muffler is less likely to make contact with trail obstacles.

How It Works
We immediately noticed a seat-of-the-pants improvement after the installation of our intake and exhaust. The JBA muffler is barely audible at cruise, but provides a pleasing increase in sound, with a better tone, at idle and under load. There is no mistaking the AEM intake under the hood, which comes to life with a thunderous roar under wide-open throttle. Overall the Jeep is a much better daily driver and the gains were more than we expected.

We dynoed the JK with the stock intake and exhaust, the AEM intake with the stock exhaust, the JBA exhaust with the stock intake, and then both together. Here are the results:
Power Gains
AEM Intake HP TQ
Peak 138.1 170
Peak Gain 3.1 5
Greatest Gain 6.6 8
JBA Exhaust HP TQ
Peak 138.6 170
Peak Gain 3.6 5
Greatest Gain 7.6 11
Peak 143.5 176
Peak Gain 8.5 11
Greatest Gain 12.6 15


Hawthorne, CA 90250
JBA Performance Exhaust
JBA Performance Center
San Diego, CA 92111

Connect With Us

Newsletter Sign Up

Subscribe to the Magazine

Browse Articles By Vehicle

See Results