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2007 Jeep JK Wrangler Engine Upgrades - Power Player

Part 6: Engine Upgrades

By Sean P. Holman, Photography by Sean P. Holman
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.
The first thing we did was strap Project 'Con Artist down to the dyno and get our baseline

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.

  • AEM's Brute Force intake is simple and includes a heatshield, an intake pipe, a Dryflow air filter and necessary mounting hardware.
    AEM's Brute Force intake is simple and includes a heatshield, an intake pipe, a Dryflow ai
  • With the stock airbox removed, we installed the AEM heatshield.
  • The AEM intake tube was then attached to the throttle body and mounted to the heatshield.
  • Next, the AEM reusable, non-oiled Dryflow filter was installed.
  • The last item to be installed was the factory intake temperature sensor into the AEM intake tube.
    The last item to be installed was the factory intake temperature sensor into the AEM intak
  • JBA's stainless steel exhaust system utilizes the JK's already free-flowing mid-pipe and replaces just the stock muffler.
    JBA's stainless steel exhaust system utilizes the JK's already free-flowing mid-pipe and r
  • Here you can see the bulky stock muffler being removed.
  • JBA prides themselves on easy-to-install exhaust systems and this one was no different. Once the factory exhaust was removed, the JBA piece was lifted into place.
    JBA prides themselves on easy-to-install exhaust systems and this one was no different. On
  • With the JBA exhaust secured, the supplied clamp was tightened, wrapping up our install.
The JBA muffler not only offers a fashionable polished tip, but the smaller muffler is less likely to make contact with trail obstacles.
The JBA muffler not only offers a fashionable polished tip, but the smaller muffler is les

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:
We dynoed the JK with the stock intake and exhaust, the AEM intake with the stock exhaust,
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
JBA + AEM HP TQ
Peak 143.5 176
Peak Gain 8.5 11
Greatest Gain 12.6 15
SOURCES
AEM
N/A
www.aempower.com
JBA Performance Exhaust
www.jbaheaders.com
JBA Performance Center
5135 Convoy St.
San Diego
CA  92111
8-88/-JBA-5570
www.jbaracing.com
By Sean P. Holman
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