Patrol 3L Turbo suitability

Firstly, welcome to the group, and if you wish to disclose further details about yourselves you can go down to members tools and then edit your profile. While there you can have a look at what others have submitted about themselves. I have also sent you an e-mail direct about the membership lists. In regard to a 3.0lt Patrol, friends of ours that we went out to Birdsville and the Flinders Ranges with in June have a 3.0lt patrol towing a very heavy 16' van. (They have outboard motor, and boat trailer on van and when fully loaded are over 3 ton) They had only recently changed from 4800 petrol Patrol because it was too expensive to run, to the 3.0lt Patrol, and are very happy with the performance and even happier with the fuel economy. We were both travelling at the speed limit and it pulled up the hills OK. We were in a 7.3 Lt F250 so it is hard to compare with such a big power difference. They had to have a manual Patrol because the manual has higher towing capacities than the auto. Brian

Re the auto, I have a manual 100 series TD. I agree
there are places where I’d like an auto, mainly hill starts with a BT in
tow and hitching the in a non level situation.

I thought momentum would be an issue but I find it very
much not the case. It certainly could do with a 6th gear above 5th.



I bought the manual for the low 1st gear
on the 100 series, and still like the selection for open road driving.



If I buy another, it probably will be auto for the
towing aspect.





----------------------

Gary Harding

TriSys Engineering/III

Gary, When you see one of the group with the F250 7.3lt auto you won't worry about another Toyota, you will go for the F250. Brian

Gary et al, As you know the torqueconverter stall speed (slip) allows the engine revs to climb further into the rev range to bring the turbo on boost earlier .... a big advantage. It brings the motor closer to max torque at slower speeds (below stall rpm). This allows smaller engines to move a larger towed load off the mark or do hill starts where with a manual it might be a case of low range, if the 4WD system in the particular vehicle allows it, just to save the clutch. The main disadvantage of autos (when towing) used to be the heat generated by the toqueconverter when slipping thereby using excess fuel and shortening there service life greatly. Lock -up torqueconverters on the modern auto now almost eliminate the converter heat from slip (still around 8% slip in lock-up mode I believe). They first used lock-up in overdrive (4th) ...which could be a trap because people were towing in drive (3rd) and still generating heat. Then came lock-up in drive (3rd) and overdrive (4th) and now most modern autos can lock the converters in all but first gear. This gives a huge reduction in the heat generated and a marked improvement in fuel economy compared to the older autos. A smaller benefit has been greater engine braking. Most modern vehicles (autos) have an overheated auto temp warning light. In the case of the F250 (TCIL, trans control indicator light) it comes on at 132 deg C. As it runs synthetic trans oil this temp would be ok for short periods but I have severe doubts about the plastic parts/ electronics surviving this temp for any length of time thereby shortening trans life. I have a trans temp gauge on my F250 and use 110 c as the absolute max before I start to cool it .... not that it has ever been near this temp (because of trans cooler). The quickest way to cool an auto whilst driving is to keep the auto in as high a gear as possible, back off to lock converter and try to keep using light throttle openings. If the overtemp light comes on ....pull over place auto in neutral or park and run engine at 1100 -1300 rpm until light goes out and then another 5 min or so then proceed again. Most owners manuals should address this under the towing section ???? Regards Anthony Explore this Great Land ... Do it Easy ... Tow a Bushtracker

For what it is worth, a Discovery TD5 auto copes quite adequately towing a fully optioned 18' BT locked up in 4 th gear at 100 kph and at 2300 rpm. It has a turbo intercooled 2.5 litre common rail injection motor. With self leveling suspension and active cornering enhancement it does not require any load distribution system to equalise the load on the tow vehicle. I don't know how the Nissan 3 litre performs towing, but I have driven a manual on outback roads and have found it a more than adequate performer. Don't be put off by the motor size - common rail technology in diesels is permitting manufacturers to go with smaller capacity motors producing near negligible emissions, almost unheard of fuel econmy and power and torque to rival motors twice the size. Check the performance specs of the VW Tauareg for example - 5 litre motor with around 750 Nm of torque and the 2005 Discovery's likely 2.7 litre producing a speculated 440 Nm. Now this should stir up a really interesting discussion! Big is not always beautiful. I do recognise that the F250 truck is a great tow vehicle and if I could afford two trucks, I'd probably have one. But, what a bitch when you have to go to town and its your only.... Myles

Myles, I noticed that on the caravan forum there was a lot of talk about low ball weights on the Disco while I believe that they have a high tow capacity. What rating does yours have? With the F250 we can have 227 and 2270 without weight distribution and 350 & 3500 with it. Brian

Myles,
I'm intrigued by your comment that self-levelling suspension can equalise the tow vehicle load and eliminate the need for weight-distribution gear. I don't doubt that it can level-up the vehicle, but how does it equalise the load? From what I read in Collyn's item on stability in the Documents folder, surely you still need wd gear?

Hi All, Thanks for the quick responce. That's given me a bit to think about. As a matter of interest the 3Litre Turbo Patrol has the similar power and torque to the 4.2T give or take a couple of Nm - 354 or 360Nm both @ 2000 RPM. There is no automatic version available in the current 4.2T unfortunately. No doubt the above torque figures not in the same league as a F250 but ball park with a Disco TD5 @ 340Nm at similar RPM. Brian, Do you recall what sort of fuel economy yours friends got with the Patrol? Regards, Peter and Leigh

Myles, I'm with Kiwi a little here .... The generally accepted need for WD hitches is a movement down of more than 15mm in the rear and say 4-6mm lift in the front after applying around 10% ballweight of the towed weight to the towbar. As you know in a self levelling suspension it takes the vehicle back to level after applying the ballweight. This does NOT remove the uplift it just brings the suspension height back to normal giving you back the right camber and toe-in settings etc but does not address the possible excessive reduction in tyre contact patch. It is easily proved .... albeit somewhat time consuming .... because of the self levelling you cant measure lift at the front/rear but you can weigh the front on a weighbridge. Place the front axle on a weighbridge and record, add your 280kg-ish from BT , let vehicle self level and record weight on axle now ...I think it will be reduced somewhat. Motleys self levelling Lexus improved greatly from a WDH he might like to comment. I realise it is your vehicle and you have travelled extensively with the setup I'm just wondering how it does it so well with 280kgs on the towbar of a Disco with no WDH ? A winch and steel bullbar might counteract this somewhat are they fitted ? It the ballweight unusually low ?? Regards Anthony Explore this Great Land ... Do it Easy ... Tow a Bushtracker

Peter, We were getting about 5km/lt and Terry in the Patrol 3.0lt was getting close to 6km per litre (I think). I know it was slightly better ecconomy than us. Brian

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G’day Brian, Kiwi, Anthony and others Discos are rated a 750/3500 Kg GTM towing capacity with a maximum ball weight of 250 Kg. At the maximum, this represents around 7% of GTM. When touring our BT’s ball weight is around 210 Kg or about 7% of the slightly less than 3000 Kg loaded weight. I read with interest from the side the WD debate thread which examined the relative merits of heavier springs, air-bag assist and the various WD systems themselves. Though that debate has been had, I will offer a few additional comments for consideration. At the outset, let me say that there is no single answer to a safe towing arrangement. We all know that it is a complex interaction of physical load distribution in the tow vehicle and the trailer, separately and in combination, together with towing speed, driver experience and driving conditions just to list a few. Physical load distribution (rather than assisted distribution) is governed by recommendations by regulatory authorities and by manufacturer’s recommendations/stipulations (both tow vehicle and trailer). Different manufacturers have different stipulations with respect to towing with their vehicles. For example, LR is quite specific with its towing stipulations – maximum 250 Kg ball weight and a clear statement that “an equalising or any other form of weight distribution tow bar should NOT be used on your vehicle”. In addition there is the insurance issue. Advice from my insurer made it plain that if the manufacturer’s towing stipulations were compromised on these matters, my coverage would be likewise compromised. The previous paragraph answers nothing – it merely restates what we all already know. Kiwi, however, posed an interesting and challenging question: how does self levelling suspension distribute load? Put simply, in much the same way that a conventional WD system does it – but less efficiently. Envisage a 4WD side on. The vehicle’s weight is translated into vertical down-forces distributed through the front and rear axel assemblies. With conventional suspensions, when loading is increased over and behind the rear axel, the ratio of the down-force through the front axel to that through the rear axel decreases. In overload situations this becomes the “gee-the-steering-feels-light!” syndrome with the vehicle seeming to pivot backwards over a side to side axis through the chassis. Rear self levelling suspension (SLS) simply matches the down-force at the rear with a corresponding up-force by inflating air bags automatically to maintain a predetermined measurement between the axel and the chassis. By doing this the minimum down-force through the front axel essential to proper handling is maintained. If you like, the effect of the pivot analogy is reversed. It does not mean that the weight is actually transferred forward (though a proper engineering analysis might well establish that some really is) it is safe to say that a proper handling balance is restored to manufacturer’s satisfaction. And, hopefully, to the users satisfaction and safety too I hasten to add! When a trailer is hitched, the down-force of the tow-ball weight becomes a rear axel load with a corresponding down-force value which is handled by SLS accordingly. Remember though that the down-force at the rear axel is a function of the tow-ball weight itself and distance of tow-ball to axel centre. WD systems essentially do the same compensatory tricks as SLS but at a more efficient point near the tow-ball/hitch point itself. Though the same end result can more or less be achieved by much tinkering with spring rates and applying air-bag assists where SLS is not a option, WD bars and hitches are a definite way to go. Critical appraisal of this explanation would be respectfully received. Myles

Self -levelling suspensions do not distribute weight from ballweight downforce they only correct the height of the vehicle back to a "level " attitude. The upforce to correct the rear sag from ballweight with the SLS is done at the rear axle ...... providing no down force at the front. The front comes down by the SLS winding it down ...you still have an uplift at the front proportional to distance from the load point to the rear axle ... and from the rear axle to the front axle as a ratio. It is a simple lever with the rear axle as a pivot point and the ballweight as a downforce on the lever. WD Hitches provide the upforce at the ball/hitch area therefore providing downforce at the front by the lever action of the bars which distributing the weight along the chassis to the front. It is hard to illustrate this in text ..... Forgetting limits and towbar/chassis strength for now try this ..... If I put 2000kgs on your towbar hitch lifting the front wheels 2 inches off the ground your SLS brings the rear up .... how does it bring the front wheels back to the ground by winding down the front ...the wheels are off the ground ??? The wheels just wind further up into the wheel arch making the distance to ground even further. If I put a 2000kg WD Hitch on now and engage the chains to level the vehicle the front is back on the ground with the tyre contact patch still the same as before the 2000kg was put on ..... and the rear is back to start height because the uplift is at the downforce point of the lever. This is all a moot point anyway I suppose as Land Rover has deemed that 250kg ballweight does not affect the tyre contact patch enough to warrant aWDH and would be risky running one with the associated potential insurance problems or potential loss of safety by them (WDHitches) affecting the LR, SLS. You've certainly had no problems and travelled extensively. Your slightly lighter ballweight is a bonus. As a side note .... When I was a 20 yr old I worked in closely with a trailer experienced engineer building a racecar trailer. I still remember him saying that 5-8% ballweight of total weight of towed vehicle was the calculation depending on trailer type. My BT runs between 7-8% ballweight at 225kg and is easier on the rear suspension than 300kg at 10 %. Regards Anthony Explore this Great Land ...Do it Easy ... Tow a Bushtracker