Suspension
An Explorer Pro Comp 3" suspension system was used on "Project ZJ" for close to a year. This system worked well for daily driving, and tackled moderate four-wheel drive trails with ease, but we?ve reached it?s limits and it is time to move on. Over a year ago, we replaced the Pro Comp suspension with a compilation of parts provided by Off Road General Store in Laguna Hills, CA. Mark Hinkley, owner of ORGS, has been considered a specialist of Jeep?s Quadra-Coil suspension since it?s introduction. Over the years, he?s had hundreds of Grand Cherokees in his shop, and sent many happy customers home with his 4.5" suspension lift. You may remember our review of the ORGS suspension in a previous issue of Grand Cherokee UnLimited. Refer to the article at http://www.off-road.com/jeep/grand/orgs/lift.htm if you need to be refreshed.

The ORGS suspension lift consists of the following parts?

• Front Parts: Rancho coil springs, ORGS 1.5" billet coil spacers, Rancho RS9000 shock absorbers, ORGS billet bump stops, ORGS upper control arms, ORGS lower control arms, JKS upper shock mounts, JKS lower shock mounts (crush type), and JKS swaybar quick disconnects.
• Rear Parts: Rancho coil springs, Rancho RS9000 shock absorbers, ORGS lower control arms, Mopar isolator pads, and ORGS isolator pad spacers.

The ORGS package includes everything you need to lift a Grand Cherokee 4.5" over stock, but there are some issues that the installer may need to address before the installation is complete. The front driveshaft will need to be lengthened or replaced with a longer unit on most vehicles, especially late-model ZJs with a CV joint-type front driveshaft. This will prevent any driveline vibration that is often noticed when installing a suspension lift. The experts at Off Road General Store can have a driveshaft custom built for your Jeep, or in some cases, you can have a reputable shop lengthen your existing driveshaft. However, "Project ZJ" experienced no vibration from the 4.5" lift, and the stock driveshafts were retained.

If your goal is to run 33x12.50 tires, as we did on "Project ZJ", it will be necessary to trim the rear wheelwells for proper fit. This process can be performed by an amateur, but is best left to a professional body shop for best results. For more information on trimming the rear wheel wells, take a look at section below, written by another ZJ owner who performed this modification.

"After the installation of my ORGS suspension lift was complete, there were still a few details that needed attention before we could mount the tires and test drive the vehicle. One of those was trimming the rear fenders to accommodate a 33" tire. With no previous experience using cut-off tools, I decided to have a professional body shop do the work. Only one of the three body shops I contacted would even consider the job. Since this was definitely an uncommon job, they told me that I needed to let them know exactly what I wanted done, which wasn't a problem. We started off by removing the plastic fascia piece behind the rear door. I told them to continue the rounded wheelwell look over about an inch and then make a new curve much closer to the door. To provide a clean and OEM look, I decided to leave a small amount of sheet metal, about a quarter of an inch in width, from below the top of the fascia on the door, down to the bottom of the door. They then trimmed the rocker panel to match the trimmed fender. Since all this cutting left some serious holes, they filled them with a black self-expanding silicon. It blends right into the black wheel well and ensures that water won't get where it doesn't belong." --- CJ Lagos

Some companies with extreme suspension systems for the Grand Cherokee utilize articulating control arms, however, Mark prefers to use a solid one piece control arm for vehicles that will be used as a daily driver. While articulating control arms often place less stress on the sub-frame and allow for easier suspension travel, the solid arms tend to be quieter on the road and provide better handling characteristics. For those looking for better off-road performance, ORGS offers an optional articulating control arm made by Currie Enterprises. These arms employ a polyurethane-encased ball joint at each end of the arm, which allows the axle to rotate with greater ease when keeping all four wheels on the ground is mandatory. It?s important to lubricate the polyurethane bushings used in the control arms on a regular basis. The use of greaseable bolts and/or zerk fittings with the arms will make this job much easier. I failed to lubricate the bushings in the solid control arms used on "Project ZJ", and over time, they began to transmit road noise into the cabin.

Mark Hinkley, owner of Off Road General Store, has perfected his 4.5" Grand Cherokee lift. Long-travel Rancho RS9000 shocks were used to allow extreme suspension travel, and Rancho springs at each corner suspend the vehicle.

Ride quality is a major factor for Grand Cherokee owners when considering a suspension lift, and has been monitored closely over the past year. Severe angles at the control arms, track bars, and steering components will lead to poor driving characteristics. Generally speaking, these angles are directly related to the amount of lift added to a vehicle?s suspension. Despite the rather extreme amount of lift gained with the ORGS suspension, ride quality and handling characteristics are only slightly affected, and the vehicle remains to be well-mannered on the road. While the vehicle isn?t as responsive to driver input as it was in stock form, it still handles surprisingly well. Adjustable Rancho shocks allow the driver to tailor the vehicle?s ride quality by simply turning a knob located on the shock absorber?s body.

Tires/Wheels
The 4.5" suspension lift, combined with the newly-trimmed rear wheelwells, allowed us to mount a much larger tire on the Jeep. Our goal was to mount the largest tire that would fit, while still allowing full suspension travel. A 33x12.50 BFGoodrich Mud Terrain tire was chosen for it?s excellent reputation and proven durability. The M/T?s tread pattern works extremely well for most types of terrain, and it?s three-ply sidewall is stronger than most competitors?, while still providing a comfortable ride. To provide extra grip on icy roads, we had the tires siped by Discount Tire. The additional grooves created by the siping process increase traction, reduce noise, and improve mileage.

When installing a 33" tire on the Grand Cherokee, it is imperative that a wheel is used with the correct amount of backspacing. Backspacing is the distance from the mounting flange of the wheel to the inner bead. Using a wheel with too much, or too little backspacing will result in excessive rubbing within the wheelwells. A wheel with the correct amount of backspacing will allow the tires to move freely during suspension travel with minimal, if any, rubbing. For our application, a 15x8 wheel with 4.5" of backspacing seems to be the best choice. When searching for a wheel with these specifications, we found that it is a fairly uncommon choice. However, a call to Centerline Wheels paid off, as they offer a complete line of billet wheels with the specifications we were looking for.

Mounting 33" tires on a Grand Cherokee isn?t as easy as it sounds. The larger diameter tire will make a noticeable difference in the vehicle?s performance, unless the axles are re-geared at the same time. Owners of V-8 models with a 3.73 axle ratio may find that performance is still adequate, but if your ZJ has the I-6 engine and 3.55 ring and pinion gears, expect some loss in acceleration. Likewise, the stock Grand Cherokee brakes will take longer to bring the vehicle to a halt. Another issue that needs to be addressed if the Jeep will be used for heavy four wheeling is the strength of the factory axles. The larger, heavier tires will create more stress on the axles, which may in turn lead to component failure in some cases. Carelessness and an inexperienced driver will only intensify the problem.

Body Armor
In the third stage of "Project ZJ", we covered the topic of rocker panel protection with the installation of Off Road General Store "Super Nerfs". As with the suspension lift, we?ve had the opportunity to thoroughly test these units and offer a long-term update on their performance. Simply put, the "Super Nerfs" have proven to be one of the greatest assets installed on "Project ZJ" to date. They have never failed to protect the rocker panels from damage, regardless of the situation And despite the amount of abuse they?ve seen, the nerfs have yet to show any signs of bending or breakage. Their dual tube design provides protection for the bottom of the rocker panels as well as the sides. On several occasions, I?ve actually used the upper bar to "pivot" the vehicle around a rock when it was too sharp to make otherwise.

The "Super Nerfs" do an excellent job of protecting the rocker panels from damage, as you can see from the pictures. Notice the rocker panel damage obtained prior to installation.

When installed on your Grand Cherokee, the "Super Nerfs" provide a location to use a Hi-Lift jack for changing tires or vehicle recovery purposes. The Hi-Lift can be placed anywhere along the nerfs, allowing you to raise either the front or rear wheels. When placed in the middle of the nerfs, both wheels can be raised off of the ground with ease, even when the front and rear swaybars are removed from the vehicle. Ground clearance is virtually unaffected, due to the low-profile design. The "Super Nerfs" have been through rigorous testing on our project Jeep, and have held up exceptionally well. With heavy use, the bars may get scratched and scraped on occasion, but with a little sanding and some black spray paint, the "Super Nerfs" look good as new. Because they mount to the vehicle?s sub-frame and lower pinch weld, they can support much more weight than a conventional nerf bar that only mounts to the frame.

Using a Hi-Lift jack!	ORGS "Super Nerfs" in use!

Summary
A tremendous improvement in off-road performance was immediately recognized with the modifications covered in stage 6. The extra clearance provided by the ORGS 4.5" suspension lift and 33" BFG tires helped immensely on boulder-ridden trails where the axles and undercarriage used to drag. And when clearance is a problem, the Super Nerfs protect the Jeep?s rocker panels from damage. These modifications alone transformed "Project ZJ" into a mean, green, trail machine that excels on any terrain.