The JBA Cat4ward headers for...
The JBA Cat4ward headers for Jeep 4.0L I-6 engines offer a mandrel-bent, stainless steel construction and provide solid performance gains throughout the rpm range. Extra-thick flanges are in place for a secure installation without leaks. A post-installation dyno run showed significant increases in horsepower and torque.
With suspension and big tires in place on a 4x4, available horsepower and torque begin to wane. While lower axle gears will help restore some of the lost engine performance, many simply get used to the feeble power and acceleration and never regain what was lost. One easy, bolt-on method to take back the power is through the installation of a set of free-flowing headers, which will decrease exhaust backpressure and make it easier for exhaust gases to escape the cylinders more efficiently.
JBA headers are tuned to increase horsepower and torque throughout the rpm range.
The headers are constructed from heavy-duty, mandrel-bent stainless steel tubing and are available with an optional titanium ceramic or silver ceramic coating. They feature extra-thick, 1/2-inch laser-cut flanges and high-flow merge collectors, along with JBA's sealing dome technology. The JBA Cat4ward headers are 50-state smog legal, include necessary hardware, and offer a simple, bolt-on installation. JBA Cat4ward headers are available for '91-'06 Jeep Wrangler and Cherokee vehicles with the 4.0L I-6 engine. JBA also offers headers and complete exhaust systems for many other engine applications.
On the Dyno While we could...
On the Dyno
While we could have easily installed the JBA Cat4ward headers on our '00 Jeep Wrangler TJ and told you they functioned as intended, we decided to really put them to the test and perform a rear-wheel dyno to get some actual performance numbers. As tested, the Wrangler was equipped with an otherwise stock 4.0L I-6 engine. The Wrangler also uses the 32RH three-speed auto trans, NP231 transfer case, 4.56 gears in the stock axles, 35-inch tires, and a TeraFlex PRO-LCG suspension system. With the JBA Cat4ward headers in place, the dyno revealed an increase of 9.4 hp and 15 lb-ft of torque.
In addition to the JBA headers,...
In addition to the JBA headers, we'll install an AEM Brute Force Air Induction System. The kit is made in the USA and is dyno-tuned to produce maximum horsepower and torque. The 4.0L Jeep kit includes AEM's lifetime Dryflow synthetic air filter, a mandrel-bent, 6063 aluminum intake tube, a powdercoated steel heat shield, and an AEM Power Spacer.
To begin the installation,...
To begin the installation, we removed the intake manifold to reveal the stock exhaust manifolds. The exhaust manifolds are two-piece cast-iron units. Jeep used crack-prone tubular exhaust manifolds in '00-and-earlier TJs. In addition to the performance benefits, the stainless steel JBA headers are also much lighter than the factory cast-iron exhaust manifolds.
With the factory exhaust manifolds...
With the factory exhaust manifolds removed, the gasket surface was prepped for the new JBA gasket. Once the gasket was in place, the JBA headers were secured in their proper location using the factory manifold bolts.
The intake manifold was then...
The intake manifold was then bolted back up to the block above the JBA headers. The remaining fuel and electrical leads were reconnected, and the stock air intake was installed to complete the install.
The Jeep was run on a rear-wheel...
The Jeep was run on a rear-wheel dyno after installation of the JBA headers. At peak gain, the JBA headers showed an increase of 9.4 hp and 15 lb-ft of torque. Considering the tests were performed on a Jeep with 35-inch deep-lugged tires, we were more than pleased with the increases.
Though the JBA headers showed...
Though the JBA headers showed ample performance increases across the board, we took the engine a step further with the installation of an AEM intake system and open-element filter. Although the system was installed after the official dyno run, our "butt dyno" revealed a further increase in power and acceleration.