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We rounded up one Pommie and a Yankee fresh off the boat and treated them to a working holiday they’ll never forget. Glenn Wright sets out to see how these two fancy, foreign 4WDs handle the Australian outback in summer.
Words by Glenn Wright
Photography by Robb Cox
This torture test was more of an initiation, a typical Aussie welcome to two naïve new 4WD models. Developmental versions of the Discovery 3 had visited Australia for some testing before it was released here unlike the Grand Cherokee that knew little of the unforgiving nature and hidden dangers that outback Australia holds in store for it. Could they hack the rough and tumble world of outback touring or were they destined to remain as city slickers?
We were impressed with the Land Rover Discovery 3 and Jeep Grand Cherokee which took out the top two spots in our 2005 4WD of the Year based pretty much on their off-road ability. Off-road ability includes slow-speed, low-range conditions and is of great importance to us as off-road enthusiasts. I am a fan of electronic traction control in these conditions and the possibilities are endless with millions of R and D dollars being sunk into it.
But, there’s been plenty of campfire discussion as to the reliability of these modern, electronically dependent 4WDs and, like many of you, I am concerned about its potential to leave you stranded far from any bugger who has the knowledge or more importantly the equipment to diagnose and repair it.
Both these vehicles can out think even the most experienced off-road drivers with their advanced electronics and computerised 4WD systems. There’s more talking going on between the sensors under the vehicle than there is coming from the outback radio DJs chattering away on the stereo.
If you believe in Murphy’s Law which says that anything that can go wrong will go wrong - and anyone who’s spent enough time in the bush will have experienced this - these wagons with their countless metres of wiring and sensitive computers on board are asking for trouble.
Let’s be honest some old-school, bush-dwelling experts want these high-tech 4WDs to experience an electrically related problem so they can say, told you so and justify their technically retarded Patrol or 78 Series ’Cruiser.
To test this I wanted to simulate the worst touring conditions I could. Here’s how we put these vehicles to the test.
TRIP NOTES
This extended new vehicle comparo had everything, the most neglected outback roads we could muster, red sand, brown snakes by the dozen, blisteringly hot days and more flies than we knew could fit on one guy’s dinner plate. We waited ’till the peak of Summer and headed west of Sydney, deep into outback NSW for a week in order to put these vehicles through the ultimate torture test. I spent hours on the phone with NSW map in hand asking locals in every outback council office and pub where I could find the worst roads. They questioned my sanity until I told them I wanted to test out a Jeep and Land Rover which made them only too keen to point me towards some roads that they gleefully predicted would give these foreign 4WDs some grief. We marked out the ones that the local postie refuses to drive down near Wilcannia, the “goat track” that the publican in Mt Hope reckons you’d have to be bloody desperate to travel on and those that local grader drivers were, “yet to get around to”. Each vehicle was loaded up with 120kg of sand, and a further 200kg of luggage, including two spare wheels, plus drivers.
DESIGN AND ENGINEERING
These two vehicles are under the spotlight because of their electronic traction enhancers, great diesel engines and foreign (ie not Japanese) design and engineering principles. They differ in suspension layout, chassis construction and number of seats. Their 4WD traction systems, while both relying on electronics, vary considerably.
The Land Rover uses fully independent suspension and airbags to vary the ride height which is great negotiating difficult off-road obstacles and benefits tourers in its ability to restore the original rear ride height even when heavily laden. The Jeep’s coil springs offer a wallowy ride but don’t sag as much as I had expected when full of gear. Both vehicles keep the dust out well especially the Disco. Surprisingly the Jeep has no front mud-flaps which caused considerable stone damage to the rear doors.
The Jeep’s suspension doesn’t permit much upward travel which limits its ability to absorb bumps and the box section rear suspension arms look like a second rate high school project. The fit and finish inside the Jeep could also be improved. The Discovery is in a different league with superior build quality in every aspect.
DRINKING HABITS
In standard form, both vehicles suffer several design limitations that hinder their ability to become good touring vehicles. The specs above highlight the annoying lack of fuel capacity in both vehicles. This almost caught us out near Mt Hope when with the fuel needle near empty, we found the fuel station ceased trading years ago. This left us with barely enough diesel to get to Lake Cargelligo.
With our hearts in our mouth the Jeep coasted into the servo with 0 km to empty flashing on the dashboard. At 14.1L/100km, the Jeep’s 77L tank will give a range of only 546 km. The Disco’s 82L tank will give a range of 569 km. Unfortunately at this point in time, there isn’t a lot buyers can do to overcome this problem. Due to previous lack of demand for Grand Cherokee replacement tanks, Australia’s largest aftermarket fuel tank manufacturers Long Ranger, have no plans to design any for the current model. The Disco 3 also has its spare wheel mounted under the rear floor. Due to the design of the original Disco 3 tank, there is no room to make a larger replacement option but there is work being done as we speak to produce a rear wheel carrier to make space for an auxiliary tank to be fitted in place of the spare. On this trip the Jeep covered 2570km and used 362L returning
14.1L/100km. Staggeringly the Disco 3 travelled 2570 and used 370L consuming a similar 14.4L/100km. This fuel economy is excellent considering the speeds at which we covered these terrible gravel roads in order to place further strain on the vehicles. Without trying to, the bitumen stretch from Sydney to Bourke saw both vehicles sip only 8.2L/100km fully laden!
If you want to fit a dual battery system to your Disco 3 then there isn’t much room under the bonnet. It would involve some reshuffling under there and at this stage would be a custom job. Ditto for the Jeep but with less room under the bonnet.
RUBBER
The Jeep Limited comes out with 245/65 tyres on 17in rims and is available with factory optional Wrangler A/Ts which is a brilliant idea and give a lot more bite off-road. The downside is they’re a bit noisy on the bitumen. The TDV6 SE Disco comes standard with 18in wheels for which virtually no aftermarket off-road options are available. It is possible to fit the 17s as an option, which we did for this test, as they still clear the front brake calipers and offer a better choice of off-road rubber as well as a taller sidewall for off-road use. There is a range of off-road rubber available for 17s now ranging from mild to wild but in many cases is slightly too large in rolling diameter to be legal in some states requiring engineering approval.
Cooper tyres offer both the ST all-terrains and STT mud tyres in 17 in but require engineering approval in some states. We wanted to minimise our chances of getting punctures, which wasn’t such an issue in the Jeep with the Wranglers on it but was a concern in the Disco. Cooper tyres offered us some Discoverer ATRs which are a mild all terrain tyre with superior puncture resistance to many O.E tyres. It is not of light truck (LT) construction but is extremely quiet on-road, and offers good wet and dry bitumen grip, important for tourers, and is great on gravel roads. We ran the tyres at between 28 and 32psi depending on the conditions and speeds at which we were travelling. On gravel they offered superb straight line braking and acceleration traction and offered good bite when you turned into slippery corners. They incurred some chunking of the tread blocks, which I have experienced with most 4WD tyres, treated in similar fashion. Most importantly, after the 2500 km of abuse we dished out to them we never got one puncture.
Are these modern 4WDs better off as tourers because of their electronic inclusions or are they victims of their advanced technology? Here’s what happened.
BITUMEN MILES
Both 4WDs were at home on the bitumen. Their well insulated interiors blocked out most road and wind noise with the Jeep’s monocoque chassis and steel coil springs transmitting noticeably more road hum through to the cabin than the Disco’s semi-separate chassis and air springs.
Each vehicle was effortless to steer but the Jeep was more communicative than the Disco via the steering wheel. On unmaintained bitumen back-roads, the Jeep’s steering suffered as it hit bumps as a result of the poor shock absorber control that required slight steering adjustments to keep the Jeep on course.
At speeds of about 90km/h and over the Jeep’s massive rear diff creates an annoying whine when you let off the accelerator and coast.
Both the Mercedes-Benz 5-speed tiptronic auto in the Jeep and the ZF 6-speed sports mode auto in the Disco change gears smoothly and offer good ratios. The Disco’s extra gear drops the cruising rpm at 110km/h to 1900rpm versus the Jeep’s 2400rpm.
The view of your surroundings varied greatly between vehicles. The Jeep with its low roof and correspondingly short windows was difficult to see out of in all directions. The view from inside and the driving position, especially for drivers over 6 foot, is sacrificed in favour of the Yank’s demand for a stylish exterior and doesn’t suit touring. The driver’s head space is limited for the same reason and after long hours behind the wheel the low roof can make you feel a bit claustrophobic. In contrast, the taller Disco has more glass than a multi-storey office block and offers a superb view from all seats.
Three factors that increase your level of fatigue after driving long distances are interior cabin noise volume such as road and transmission noise, lack of engine torque and lack of cabin space. Wayne Thomas, our experienced guest driver and I, split the driving between each vehicle evenly.
The Jeep’s amazing, endless supply of torque from low revs made covering the long stretches a breeze and made you want to put pedal to the metal more often as the feeling of acceleration became moorish. The Grand Cherokee has no turbo-lag, which can’t be said for the Disco, and pulls like a train from 1800rpm to 4500rpm also outdoing the TDV6 in that respect, but its cramped interior and increased level of cabin noise due to the coarser engine note and road hum that was transmitted through the monocoque chassis detracted from this.
In comparison, the Disco still had ample torque and its whisper quiet interior and supple, long-travel airbag-suspension isolated you from the road allowing the scenery to pass by effortlessly as if watching it in a movie theatre. It accelerated more smoothly than its competitor and left you feeling more energetic after a long day’s driving. The Jeep’s soft shock absorbers can make you feel like you’re at sea but it is more predictable than the Disco and fun to drive quickly on smooth roads. Rough gravel roads paint a different picture.
ROUGH STUFF
This is what we came all this way for and offered some useful feedback regarding the suitability of each vehicle towards rough roads. The Jeep still displayed superior agility on the smoother gravel roads and was a blast to throw around. Its ABS was well sorted and its brakes were superior to the Disco’s in their bite and stopping ability. The Jeep’s centre-diff distributed torque front to rear seamlessly. Its Electronic Stability Program (ESP) system that takes over when you corner more quickly than the road conditions allow, cuts in just after you feel the vehicle begin to slide and pulls you back into line without fuss. The Disco’s Dynamic Stability Control (DSC) performs a similar role equally as effectively but is noisier in operation and more obvious. It cannot be completely de-activated in high range, whereas at the touch of a button the Jeep’s intervention system can be turned off which gives you back control of your destiny and allows for some shenannigans if you are that way inclined.
Both these systems offer a dramatic increase in safety on slippery roads and you would almost have to forget to steer in order to get into trouble.
Larger washouts and dips in the road posed problems for the Jeep especially when trying to follow the Disco. The Land Rover would glide effortlessly over sharp edged cattle grids and washouts while the Jeep had to wash off speed as it approached such obstacles.
When you hit washouts too quickly (at the same speed which the Disco had just unknowingly flown over them), the Jeep bottomed out severely in the front and the monocoque chassis transferred every bit of noise and jarring from the bump-stops through to your body. After the first such incident we inspected the front spring towers expecting to see something penetrating the bonnet which wasn’t the case. As the Jeep hit smaller dips at speed, it launched off the other side and continued to pogo up and down, due to the lack of damper control, for the next 100m which was very unnerving.
Corrugations didn’t phase the Disco, while the Jeep’s dash shook and the whole thing shuddered back and forth across the road and steered from the rear because of the useless shocks, heavy live rear axle and short rear trailing arms.
Locals we spoke to in the pubs who had travelled the same roads as we had each day were complaining about the conditions. We had driven over these roads at pretty high speeds with no idea as to what the locals were talking about. Even though the Jeep was vulnerable on these rough surfaces, it completed them largely without drama, which showed us the high levels of comfort and bump absorption that these modern 4WDs offered when compared to 4WDs of the past.
CONCERNS
On two occasions I was left wondering how I would get these two whiz-bang vehicles from where they stopped working all the way back to Sydney.
I began to question the benefit of the electronics to tourers first when on an isolated sheep station miles from anywhere, the Disco’s dash lights began to flash at me indicating that the stability and traction control systems had failed. At this same moment, as we were negotiating Spinifex bushes half way up a sand dune, the airbags all dropped the Disco flat on its belly. After plenty of looking and head scratching, what else can you do, I turned the ignition off and restarted the engine which saw the Disco lift itself up, stop flashing its lights and act as if nothing had happened.
Not five minutes later, whilst climbing a small red sand dune nearby, the Jeep’s dashboard started warning me of a transmission overtemp, just as it stopped sending drive to the wheels and refuse to change gears. I instantly thought of you, readers who may consider buying such vehicles to use in these conditions, and what options you would have to get going again. Apart from ringing Land Rover or Jeep I couldn’t come up with any then I looked down at my mobile phone and remembered that I wasn’t within coooeee of mobile reception. Good luck!
After a while I restarted the Jeep and it drove normally again. Unlike the Disco 3, while the Jeep was tested rigorously throughout the world, it was never tested in Australia before its release. Its auto transmission cannot handle low-speed sand driving in summer as it overheats the fluid and stops working until it cools down. It is designed mainly for American buyers who need 4WDs to get around town when it snows half the year in the cooler climate.
Here is Land Rover’s response when I asked why the Discovery 3’s electronics shut down.
Hi Glenn,
The Engineering Department has asked me to pass on the following information regarding AD30QO.
Upon further testing by Land Rover Australia, condition did not recur with original wheel and tyre fitment.
Possible causes;
-Historical fault code logged
-Trailer wiring connected to vehicle
-Temporary intermittent voltage supply to park/neutral switch and/or low vehicle battery voltage.
This basically says that Land Rover don’t know what caused the problem. The Disco will usually reset itself after turning the ignition off and on again. However the following day the same thing happened. When travelling along a gravel road at 100km/h the airbags dropped the Disco to minimum height and the dash flashed at me. By pulling over and restarting the ignition it drove home without recurrence.
PARTING THOUGHT
The Jeep isn’t designed for Australian conditions and it shows. While it survived a fair amount of abuse on this test, it would not tolerate this punishment for too long. As I have seen in previous models, if used off-road often enough, the Grand Cherokee will eventually crack where the front section meets the front firewall as there is very little reinforcement to support heavy landings that force the front spring towers up. On the plus side, the traction and stability control is great and the V6 turbo-diesel engine is brilliant and far superior to the TDV6. It handles nicely on well formed roads but would benefit greatly from decent shock absorbers. Its interior is very luxurious and accommodating and would be ideal for 4WD trips on weekends but don’t take it near sand or buy one with intent to tour. Its cramped interior limits passenger comfort and luggage space. If used outside the city its stars and stripes, spongy suspension and inadequate chassis construction will reduce its life expectancy considerably.
The Disco 3 is fantastic on all surfaces and gets better as the roads get rougher. It is robust and was never bothered at any speed on any road surface. Its high roofline, spacious, well appointed interior, air suspension and effective engine and gearbox combination make it a fantastic touring vehicle. Unfortunately the small fuel capacity is a negative and I am yet to be convinced as to the reliability of its electronics in remote areas.
SPECS
To make this torture test relevant, we compared two 4WDs with similar spec and pricetags.
Let’s take a look at the spec sheets side-by-side.
MODEL: 2005 LandRover Discovery 3 TDV6 SE 2005 Jeep Grand Cherokee Limited CRD
BODY: 5-DOOR 7-SEAT WAGON 5-DOOR 5-SEAT WAGON
CHASSIS: Integrated Body on Chassis Monocoque
ENGINE: TDV6 CRD 3.0
TYPE: turbo-diesel, common-rail V6 , intercooled
DISPLACEMENT: 2720cc 2987cc
COMPRESSION RATIO: 18.0:1 18.0:1
MAX POWER: 140kW@4000 160kW@4000rpm
MAX TORQUE: 440Nm@19000 510Nm@1600-2800rpm
GEARBOX: 6-Speed auto (+/-) 5-Speed auto (+/-)
rpm@110km/h: 1900 2400
4WD SYSTEM: Full-time 4WD, high and low range Terrain-Response Quadra-Drive II
SUSPENSION:Front- IFS, double wishbones, IFS, double wishbones,
airbags, coil-over dampers,
anti-roll bar anti-roll bar
Rear- Independent, multi-link Live axle, 5-link,
airbags , dampers, coil springs, dampers,
anti-roll bar anti-roll bar
SAFETY: 2xfront airbags 2xfront airbags
Front and rear curtain airbags Front and rear curtain airbags
BRAKES: 4-wheel ventilated discs 4-wheel ventilated discs
with ABS with ABS
WHEELS: Alloy 17in (opt) Alloy 17in
TYRES: Dunlop H/T Goodyear Wrangler all-terrain
255/60R18 (std) great off-road factory
235/70R17 (opt) option245/65R17
OFF-ROAD STATS:
App/Ramp-over/Dep angles: 37/28/30 34/20/27
GROUND CLEARANCES: I measured the following heights with a tape measure
SILL HEIGHT: 300 (+55) 320
LOWEST REAR COMPONENT: 180 (+55) 210
FRONT SUMPGUARD: 210 (+55) 220
CARGO VOLUME: 1260/2558L(great) 978/1909L(poor)
KERB WEIGHT: 2432kg 2169kg
GVM: 3230kg 2585kg
GCM(max mass of 4WD +trailer): 6730kg -
ROOF LOAD: - 68kg
TOWING CAPACITY: 3500kg braked 3500kg braked
750kg unbraked 750kg unbraked
PRICE (RRP): $74,950 $69,090
WARRANTY: 3yr/100,000km 3yr/100,000 |
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