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Toyota 4Runner wagon in expanded size sports new powertrains
Bob Plunkett
Date Posted: 5/10/2005
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GLENEDEN BEACH, Ore. -- The steep slope on a rough trace cut across Oregon's rugged Coast Ranges presents a challenge for four-wheeling through tall timber in a new rendition of Toyota's mid-size 4Runner sport-utility wagon.
Loose dirt and chat on the trail often causes even nubby mud and snow tires like 4Runner's P265/65R17 rollers to slip and skid on a steep descent, which in turn may propel the vehicle faster than prudent to maintain steady control for safe passage down the grade.
No way that runaway momentum will occur with Toyota's new wagon, however, because it stocks sophisticated electronic controls linked to the four-wheel-drive (4WD) system as well as the anti-lock brakes (ABS) and active traction (A-TRAC) and vehicle skid control (VSC) devices.
The specific equipment, labeled Downhill Assist Control (DAC), is designed to keep the wagon's tires firmly planted on a steep grade as wheel speed sensors feed data on both wheel speed and the direction of wheel rotation to an electronic control module connected to the smart brakes and electronic throttle.
To operate the tool, simply activate a console switch marked "DAC" and set the 4WD transfer case to "L4" (four-low). Then proceed down the steep grade -- but be ready for the mechanism to groan and moan.
The DAC indicator light blinks on and off as the equipment goes to work, selectively squeezing brake calipers to retard the discs or adding engine juice via the electronic throttle.
As if by magic, the weighty wagon creeps down the hill at a virtual snail's pace while DAC equipment holds it on the steep grade. Driver's feet deliberately stay away from brake and accelerator pedals because 4Runner is designed to do all of the hill-hugging work on its own so you merely steer it down a treacherous grade.
Another mechanism called Hill-start Assist Control (HAC) functions as the opposite of DAC by preventing the wagon from rolling backward when scaling a steep slope.
The DAC and HAC devices represent only two of numerous new mechanisms controlling the redesigned 4Runner.
Toyota started from scratch when reinventing the wagon.
It's longer and broader than the previous issue with a bigger cabin and more comfortable accommodations, plus it carries stronger and larger powertrains and all of those high-tech controls like DAC and HAC and VSC.
Yet the new design remains true to 4Runner's origins tracing back to the initial version introduced in 1985: It's a truck-tough vehicle designed for serious work on dirt or pavement.
Like a truck, 4Runner is built on a body-on-frame chassis. The new ladder format has boxed rails extending for the length of the platform and nine cross members to maximize torsional rigidity.
Suspension amounts to an independent double wishbone design up front with coil springs over gas shocks and a solid axle in back set in four-link scheme also with springs on shocks.
The top model with a big engine offers optional air suspension for enhanced performance when hauling or towing hefty cargo. Linear height sensors vary the chassis height automatically depending on the weight of the load.
Also available is a sport-tuned suspension with compression chambers in shock absorbers cross-linked diagonally by a control unit. The system automatically stiffens outboard shocks when turning on rough roads to check pitch and roll of the body for tighter control.
A disc brake mounts at each wheel with electronic controls for the ABS, brake assist (BA) and electronic brake force distribution (EBD) equipment.
Unlike most trucks, however, the steering is controlled by rack and pinion with variable-gear power assistance. It reacts quickly and feels firmly weighted.
Previous versions of 4Runner carried powertrains containing four or six cylinders, but the new editions pack more muscle from a new V6 engine or a big V8.
Top version adopts the 4.7-liter V8 and full-time 4WD system found in Toyota's larger Land Cruiser and Sequoia wagons.
The V8 -- dubbed by Toyota as the iForce engine, with the "i" denoting an intelligent application -- has an iron block fitted with aluminum alloy heads and twin cams on top.
It makes 235 hp at 4800 rpm and 315 lb-ft of torque at 3400 rpm. The impressive low-end torque suits tow-haul chores, as it can tow a rig weighing up to 5000 pounds.
A new 4.0-liter V6 is also on tap, pumping 245 hp at 5200 rpm and 283 lb-ft at 3400 rpm as one of the strongest six-packs for the mid-size class of wagons.
An electronically-controlled four-speed automatic transmission goes to the V6 but a new five-speed automatic works on the V8.
Both 2WD and 4WD versions of 4Runner are offered.
For the V6 a multi-mode 4WD system with limited-slip open center differential can selectively switch between 4WD and 2WD modes. It's particularly suited for slippery or wet pavement as the system feels rooted to the road with power supplied to all wheels for consistent traction.
The V8's 4WD is a full-time system in two speeds with locking differential. In lock mode, the system splits torque evenly front to rear, with rear wheels turning in unison and front wheels swaying torque to wheel traction. This system works well for tackling trails and off-road terrain.
Three trim grades go to 4Runner as the base SR5, sport-tuned Sport and deluxe Limited. Visual cues set them apart.
SR5 shows gray metallic bumpers and cladding with black mirrors and mudguards and 16-inch steel wheels.
Sport gets a hood scoop, grille and door handles painted silver with silver roof rails, foglamps in the front fascia and six-spoke 17-inch alloy wheels.
Limited goes to monochrome with color-keyed bumpers and cladding but painted silver running boards and roof rails plus five-spoke 17-inch alloy wheels.
The spacious five-place cabin in 4Runner shows fabric seats for SR5, a sporty cloth pattern for Sport and plush leather in Limited with power controls plus internal heaters for the front bolstered buckets. A bench in back splits 60/40 and seatbacks fold flat to expand the rear cargo bay.
Options extend to a moonroof, DVD-based navigation system, a 360-watt JBL sound system with ten speakers, and both side-impact and curtain-style side air bags for any trim.
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| Vehicle Specifications: |
| 2003 TOYOTA 4RUNNER Specs |
| Description: |
5-door mid-size SUV
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| Model Options: |
5-door mid-size SUV
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| Wheelbase: |
109.8 inches
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| Overall Length: |
189.0 inches
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| Engine Size: |
DOHC 4.0-L V6
DOHC 4.7-L V8
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| Transmission: |
V6: Auto/4 ECT-i
V8: Auto/5 ECT
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| Drive: |
V6: 2WD (rear)
4WD (multi-mode)
V8: 2WD (rear)
4WD (full-time)
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| Braking: |
2WD: Power 4-disc/
ABS/BA/EBD/TRAC/VSC/
HAC
4WD: Power 4-disc/
ABS/BA/EBD/A-TRAC/VSC/
HAC/DAC
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| Airbags: |
2 (front)
+ opt. 2 (side)
+ opt. 4 (side curtain)
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| Gas Mileage: |
V6 2WD: 18/21 mpg
V6 4WD: 17/20 mpg
V8 2WD: 16/20 mpg
V8 4WD: 15/19 mpg |
| Price: |
$ 25,000 to $ 39,000 |
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