Project Pathfinder Part 4, Suspension Part 2
Now that we have the sagging springs, excess lean in the corners, bottoming out, bouncy ride and high speed oversteer of Project Pathfinder taken care of, we now turned our attention to the front suspension in our quest to tighten things up and fix the weak points of the Nissan steering system.
When attempting to align Project Pathfinder after last installments installation of parts we were frustrated because we could not seem to set the toe correctly. The toe settings would change every time we tried to check them whether we try to adjust them or not. The wife was complaining about loose and wandering steering as well. Having a friend move the steering wheel back and forth while we watch showed the Project Pathfinders steering linkage was seriously worn. The center link and idler arm had about ½” total play in them although the ball joints were tight and in good shape still. Those who off road their Pathfinder frequently know that the steering system is the weak point of the D21 and WD21 line of Pathfinders and Frontier trucks. Although the suspension is pretty beefy, the steering linkage is pretty wimpy when comparing it to what’s found under domestic half-ton trucks for example. Some hardcore off roaders have been known to break there steering linkages every few hundred feet of tough trail.
Spencer Low Racing and Calmini make super heavy duty steering linkages for Nissans but since this is not a hard core trail truck we decided that we didn’t need this radical of a system for our use, but we would like to beef up our steering somewhat, at least to improve response and for longer life. We replaced our worn out center link with a brand new genuine Nissan one solving that problem. We rebuilt our stock idler arms worn out wimpy plastic bushed idler arm with some solid bronze parts from Spencer Low Racing. These bronze parts press right in and should last an order of magnitude longer than the amazingly wimpy stock plastic parts.
We did not want our new tightened steering linkage to wear out so easily nor did we want to bend our idler arm so we reinforced it with Automotive Customizers idler arm brace. This sturdy steel brace reinforces the idler arm preventing loose steering flex and greatly strengthens the idler arm by bracing it to the frame. Automotive Customizers is perhaps the best source of Nissan truck off road parts on the net. Automotive Customizers also provided us with their steering damper.
|Steering Damper Installed|
The steering damper prevents steering shimmy and shake and takes a lot of stress off of the steering system by cushioning road shock increasing its life. The steering damper also reduces the amount of steering kickback, which can break your thumbs encountered while driving off road. Lastly the steering damper greatly reduces the loose steering feeling and wander in crosswinds and highway driving, just what we need for towing. The AC Steering damper uses a Rancho RS5000 shock modified for 50/50 damping. This provides the cushion for the steering system. A sturdy steel bracket attaches one end of the Rancho shock to the frame and another clamps onto the centerlink and secures the other end of the shock to the steering system.
|Idler Arm Brace|
|Assembled Arm Brace|
|Spencer Low Idler Arm Bushings|
To increase the amount of available wheel travel we replaced the thick Nissan top out bumper with Energy Suspensions Urethane low profile bump stop. This allowed us to raise the front suspension more, gaining wheel travel but still maintaining a good amount of droop travel so the truck would not rebound hard off of bumps. To prevent harsh bottoming we used some of AC’s poly foam bumpstops.
These bumpstops are made of soft microcellular urethane and are slightly taller than stock but progressive in stiffness. The idea is that they will gradually get stiffer as the downward travel increases so you won’t get a harsh bottoming out. In the rear we used AC’s urethane 2.5” bumpstop replacing the nearly 5” thick stock hard rubber bumpstop. This not only gave us an extra .25 inches of wheel travel but also improve articulation of the rear suspension. The AC rear bumpstops were for a D21 truck and needed to be slightly modified to fit on the back of the WD21 Pathfinder. This was a fairly simple task of welding the bumpstop plate to another one with the bolt holes farther apart. With the new bumpstops Project Pathfinder now has another 2.5 inches of rear and 1.5 inches more bump eating front wheel travel than stock without creating a tippy raised up monster truck.
To tighten up our suspension further and give improved steering response we replaced all of our mushy old rubber bushings in our suspension with hard polyurethane parts from Energy Suspension. We replaced our upper and lower control arm bushings, our tension and compression rod bushings and our front and rear sway bar bushing with hard urethane. If you did not have the budget, the tension compression rod bushings make the biggest difference for steering feel and handling of all the bushings. The bushings greatly increased steering precision and feel and reduced body roll due to the much firmer than stock sway bar bushings.
As the final step, we took Project Pathfinder to Darrin Nishimura, of West End Alignment, the best damn chassis shop in town. You probably notice that all of NPM’s project cars and personal street cars come here for work. There is a reason; Darrin is simply the best chassis guy out there. We still pay for our work with Darrin but the entire staff will agree that Darrin works miracles on your cars handling. West end set up Project Pathfinders front end to have about 1.2 degrees of negative camber with 3 degrees positive caster and zero front toe to help keep the rubber to the road without compromising tire wear. Darrin noted that Project Pathfinders tight front end made it much easier to align than the typical Nissan truck.
The transformation to Project Pathfinders handling is amazing, although not a sports car, Project Pathfinder can now probably out corner many sedans and just about any stock SUV. The wider track of the Volk wheels with the wider more highway biased Yokohama AVS tires and the greatly reduced body roll reduces the chance of the vehicle flipping greatly. Extreme cornering was tried in a controlled area by some of NPM’s experienced race driver staff and the Pathfinder showed no tendency to roll just showing a slight tendency for understeer at the limit. We don’t claim that we made the Pathfinder roll proof but it is a large improvement over stock. The ride is not harsh but firm and well damped, an improvement over the stock bouncy seasick ride.
When testing over big dips and railroad tracks we compared Project Pathfinder to a modified Chevy S10 with a complete Pro-Comp suspension 5” lift suspension package which consisted of control arms, shocks, spindles, and springs. When hitting big bumps hard, the S10 would bound off its top out bumpers step sideways and nearly go out of control. As far as regular cornering performance, forget it. Project Pathfinder would just go bloop and soak the bump up and was capable of going as fast as the test driver was brave enough for. We also compared Project Pathfinder to our team tow vehicle, a highly modified Ford F250 super duty with a custom long travel kit consisting of Pro-Comp springs, control arms and spindles with custom hoops and dual Fox long travel remote reservoir racing shocks. Unbelievablely, Project Pathfinder was better at soaking up the bumps and handling than this greatly modified truck, which seemed underdamped and floaty when pounded hard.