2006 Ultimate Adventure - 2007 Toyota FJ Cruiser Buildup - Part 5

We also installed a set of nitrogen-charged Jounce Shocks from Light Racing. The coilovers act as both the spring and shock absorber, while the Jounce Shocks are special bumpstops with adjustable compression and rebound to protect the suspension against bottoming out, and help in controlling axle movement at high speeds. Next month we will go into greater detail of how these new products can be applied to your project.

In the rear we used the stock shock location for our coilovers. Since the coilovers must support the weight of the vehicle, we had to beef up the frame mounts. We chose to mount the shocks to our lower link arms, which required some additional reinforcement along with special bushings on the lower shock mounts to keep the links from rolling over. All of the lower links on the FJ use Currie style rebuildable Johnny Joints where all the uppers use Heim joints.

In part two of the Ultimate FJ buildup (Aug. '06), we showed you how Fab Fours took measurements to build new front and rear bumpers for our Cruiser. After they were completed Greg Higgs brought them out from Colorado to help us install them. The front bumper bolted on and was equipped with a 9.5ti winch from Warn as well as custom Hella driving and marker lights.

We used the forklift to help us heft the rear bumper into place. Though the bumper was designed to bolt on, we added other gussets and eventually fully welded the bumper into place. These bumpers are made of 3/16-inch plate and though we would ultimately need to trim them for our extra large 39-inch BFGoodrich Krawler tires, they definitely added to the burly look we were shooting for.

With a truck that will weigh more than 5,000 pounds and only a V-6 to push it around, we started looking for options to give the aluminum block 4.0 some help. Our previous experience with supercharged V-6s had us hunting for a blower, and only one version is available for this new Toyota engine. The team at Underdog Racing Development (URD) answered our call and brought their new Rotrex centrifugal supercharger kit with them. Similar to a turbocharger, the Rotrex centrifugal supercharger increases boost with rpm, but it is also extremely efficient, compact, and reliable with no internal belts or gears.

To keep our buildup on schedule we somehow conned the owners of URD to not only meet us at All Pro to look at the FJ, but also fly in their top engineer from Maryland to install the kit on a blazing hot Saturday. The entire kit was so new that having them there to install it was priceless. Though it looks complicated, they had this premier kit installed in less than two days.

The URD system also incorporates an intercooler and oil cooler. Luckily we were installing the Fab Fours front bumper the same day as the coolers and found that some custom brackets were needed to make everything fit together without interference.

Some ECU adjustment is needed to keep the fuel program happy with the increased airflow. URD's preprogrammed performance calibration unit also addresses engine timing and is plugged directly into the under-dash stock engine computer. There is also one additional fuel injector installed, also controlled by the calibration unit. In previous testing URD has achieved a 95 hp gain at the rear wheels of a two-wheel-drive truck with only 6 psi of boost. Though we didn't get a chance to dyno our FJ, we did feel that we had excellent performance from the supercharger.