If you didn't catch our previous two issues, you missed out on an award-winning suspension upgrade for Toyota's FJ Cruiser. No matter, you can always order back issues, or check out our website (www.oramagazine.com) to get caught up. As a quick recap, we covered the origins and design of the FJ, along with how Pro Comp developed a six-inch lift that makes room for 18-inch wheels and 35-inch Mud Terrain tires.
For those who have been following along, it's time to focus on the premium setup. While stock struts can be used with spacers via the Stage I version of the lift kit, for improved performance, Pro Comp offers the Stage II, with MX2.75c Coil Over front shocks and MX6 adjustable mono-tube rear shocks.
What's so special about these dampners? As with Toyota's FJ Cruiser, its helps to take a quick look back at their history.
Pro Comp Suspensions' shocks were developed using technology learned from more than 20 years experience in off-road racing. These high-end shocks are machined, assembled and tested exclusively in-house to exact specifications and standards.
What this hard-won experience has lent to in the design of the MX2.75c coil-over is the use of a larger diameter piston with a stacked disc valve design. These components, combined with the increased fluid volume of the 2.75-inch diameter mono-tube canister, provide superior damping to deliver excellent ride and handling.
How so? In part because the thick-wall, DOM (Drawn Over Mandrel) tube has a burnished finish on the inside wear surface. Burnishing compacts the surface molecules together to create an extremely durable, low-friction surface. This process eliminates porosity normally found in honed tubes, multiplying internal seal life as much as three to four times, according to Pro Comp.
In addition, increased wall thickness maintains concentricity under heavy loads and accelerated thermal changes. This stability in high heat is important because, as students of Suspension 101 already know, shocks function by converting kinetic energy into thermal energy.
These types of stresses are why the sintered piston is made from a proprietary metal alloy and uses a one-piece, aerospace grade friction ring, impregnated with graphite and Teflon for heat and abrasion resistance. Also, the chromedsteel rod is induction-hardened to 105,000 psi, providing the required rigidity for accurate alignment of the seals, ensuring extended life without premature oil leakage. The lubricant is a race-quality oil that resists foaming and thermal breakdown.
The shocks also feature 300-psi of nitrogen stabilization, and since there's no Schrader valve, any reduction in pressure is virtually eliminated. (Again, students of Suspension 101 are aware that nitrogen makes room for the shafts yet minimizes pressure on the oil.) The Viton O-rings are doubled throughout for assured sealing.
Note, too, that the compression and rebound valving is specifically designed for the weight and suspension action of the FJ Cruiser. This custom tuning is another reason why the Pro Comp lift just feels and rides right in an off-road application.
Working in conjunction with the shocks, the springs are computer designed to the correct rate for the vehicle. They are also hot wound, shot-peened, and factory preset to ensure comfortable ride quality.
Powercoating and anodizing of all the components create a clean, durable finish. Of course, once you head off-road, they'll get covered with dirt pretty quickly, but it's good to know just what's underneath when you hit a challenging trail.
SOURCE
Pro Comp Suspension
800-776-0767
www.procompmotorsports.com
CAPTIONS
The eyelets on the MX2.75c shock is constructed from a TIG-welded alloy steel with a clear zinc finish.The eyelets employ Teflon-lined 4130 spherical bearings on both mounting ends.
(left) This closeup of the MX2.75c Coil Over on a display board shows the CNC-machined construction and the high-quality anodized finish.
(center) Note the adjustment knob on the MX6 rear monotube shocks, allowing the driver to fine-tune the ride quality depending on load and trail conditions.
(right) In addition to using precisionmachined components, assembly of the shocks requires a race-quality oil that resists foaming and thermal breakdown, along with 300-psi nitrogen stabilization.
(left) In addition to an internal hydraulic extension stop, the Pro Comp lift features an external urethane compression stop, which controls the energy at either extreme.
(center) The coils and other components are computer designed for precise ride quality.
(right) Shown here are Pro Comp's black, powder-coated Xtreme wheels. (Note: with the lift kit installed, 16- or 17-inch rims cannot be used.) They can range from eight to nine inches wide, with up to 4.75 inches of backspacing. These rims are wrapped with Pro Comp 35x12.50 Mud Terrain tires.
