Switchgear for the traction-aid systems, such as Multi-Terrain, Crawl Control and locker,
What We'll Do
The number of ways to build an overlander, and the parts required to do it, are as numerous and varied as the types of overlanding you may prefer-desert outback, wooded mountains, snowy tundra, tropical rain forest, deep water crossings, you name it. We're still researching our possible buildup options, and canvassing potential parts suppliers for this project, but here's a brief rundown of what we already know we want to do (and not do).
Engine/transmission/transfer case:
The 4.0L V-6 is perfectly acceptable in stock form, though it generates its peak power near the top of the powerband, has a kind of "dead spot" in its torque curve between 1,500 and 2,500 rpm, and sudden-burst acceleration-such as when passing slower traffic-can be sluggish and unpredictable at times. Since we're certain to add several hundred pounds of weight to the vehicle before we're finished, we'll look into perking up the 4.0L's performance parameters via a free-flowing aftermarket air intake, a less restrictive after-cat exhaust, and possibly a tuning chip with the aim at providing a little more oomph at lower revs. To better cope with the miles of dirt and dust we'll see, we'll look to improve our rig's filtration of fuel, oil, and air.
Other stuff:
we're still mulling over the addition of a snorkel-style intake, since we don't plan to submerge our project in six-foot-deep water, and the design of most aftermarket snorkel kits could cause interference problems for the roof rack/fold-out tent system we plan to install. The stock transmission and transfer case will be left unmolested for now, though we will look into cooling and skidplating upgrades for these gearboxes, and for the fuel tank as well. One last underhood modification will be the installation of an auxiliary battery to provide extra juice for the winch, lights, compressor and other amp-sucking add-ons we plan to install; we may also choose to upgrade the alternator as well.
The 270hp 4.0L V-6 is more than adequate for the 4Runner in stock trim, but since we'll be
Suspension/axles/tires/wheels:
As it's generally not built for hardcore four-wheeling, your typical overlander doesn't run an inordinate amount of suspension lift. Our 4Runner's wheelwells easily accommodate 31.6-inch-tall tires, and could probably clear 33s by simply removing the plastic fender trim. However, we'd lose some much-needed up travel as a result, so we'll be looking to mildly lift our overlander to fit 33x12.50 tires. To achieve the modest amount of lift we'll need, we'll probably opt for one of the many aftermarket kits that are available for this truck that feature longer-than-stock, medium- to heavy-duty coil springs; longer-travel shocks are on the wish list, too.
As mentioned, our 4Runner's already equipped from the factory with a rear locker, which works well and which we're happy to retain. For the IFS front, we'd normally be satisfied with adding a limited-slip-type differential, but we're leaning instead towards installing a selectable locker since we're not going to overstress the front axle assembly with a too-massive tire size. Also, with only a four-percent overall increase in tire diameter, we probably won't need to re-gear the axles, which will save us time and (a lot of) money.
Tire and wheel brands are still being debated, though we all agree that ditching the weakish OE P265 HTS treads currently on the vehicle in favor of a set of 33x12.50 radial Mud-Terrains will be a substantial upgrade in itself. Wheels will likely be in the 17x8 size and made of aluminum instead of steel to keep weight gains at a minimum.