Just some positive fuel figures for the ecoDiesel towing with a tune

[Mousie]

Hi Folks,

Well, just finished a 9K Tasmania Trip and after calculating by fuel receipts came in at a suspected low 14.3L/h. So Murchinson Generic Tune (not dyno) and front A/T's 45psi and Rears 55 psi from a tyre calculator this time was the only change from SA trip. Max Vehicle GVM and 6100T all up. I still cannot believe the low result as had to recheck for a lost receipt and even added a 60l for any top up errors. I can only assume we unhitched the vehicle a lot more and the SA trip was perhaps less unhitching.

Our past SA Trip of near same 9K was 15.7L/h and only difference was I had the tyres at 48 psi on the rears from my educated guess. High winds a plenty and driving like an old man when no one behind so 85-93ish outside of foot down when traffic and quality road enabled.

Now the Trip to Tassie had no real headwinds to contend with but a lot of hilly and winding blood cold and wet driving whereby your working the engine well into the upper torque band 2000+rpm with a million 25-35klm yellow advisories sharp corners. If you have been on tassie roads they like corners!. Dont start me on hills and dips either as spent most time manual gears engine braking as well.

I did burn through a litre of oil for my efforts on each trips as I know I have to top up every 4k to keep the dip stick at max and and about 250mil of this falls out via the catch can. If a poster online ever posted a low 14 ish I would be the first to call bull but stand corrected. The rear Bridgestones dropped 2.5mm for each trip as they are on max axle load of course.

To me, it seems the tranny gearing and powerband just do the job admirably without much fuel efficiency trade off and certainly make a ford ranger engine for example appear thirsty. Just posting for interest sake as we all know they are fuel efficient so will be a sad day for me when I have to find another vehicle. Just ticked over 119K so its not going anywhere yet. Also I suspected the Tune was not more thirsty but it took these two different trips to actually find out for myself.

[Jeeper6]

That is amazing result given the terrain...I have done the lap of Tasmania and can attest to the plethora of slow tight corners...plenty of hills and drops...and generally low speeds overall.

Was that Stu's $1000.00 ECU tune up? I spoke to him about getting that done on mine, just haven't done so yet. I have been thinking I should pull the ECU out of my old Jeep, and get it tuned so as to have a spare standard ECU on hand.
The tune allegedly loses much of the EGR activation as well which could only be a good thing.
I guess my average of 15.37 litres per 100k over the 25,000 K lap seems about the average when .towing a van...I estimate too I wouldn't have done much more than maybe 1200km over all unhitched. My GCM too is more like 5700kg...and I ran the Jeep rears at 40psi, fronts at 38psi...and van close to 40psi.
Though I also put some of my mpg loss down to fat mud tyres, bullbar, roof rack etc...

[drover]

They are really good figures for that sort of terrain but so many variations between set ups, what did you get then when back in real world country ??? ................

[Mousie]

Murchisons, ECU tune. Mainly did it for EGR turn off. Whilst I have been around cars for a long time, the major variance was now using a calculator for final psi from load rating etc. once changed to LT tyres on car and van (49 psi). In my case I knew the wheel weights from a free weigh in with Caravan Qld. I guess the only main point is the overall general consumption over near 20k by fuel receipts post a tuned ECU had not noticeably increased the overall consumption perhaps. Around town and general mix of highway as much as possible the onboard computer is 10.5 plus ish so figure that was just normal with car and alloy bullbar. No different to anyone else posting either tuned or not.

[drover]

Originally Posted by Mousie

Murchisons, ECU tune. Mainly did it for EGR turn off. Whilst I have been around cars for a long time, the major variance was now using a calculator for final psi from load rating etc. once changed to LT tyres on car and van (49 psi). In my case I knew the wheel weights from a free weigh in with Caravan Qld. I guess the only main point is the overall general consumption over near 20k by fuel receipts post a tuned ECU had not noticeably increased the overall consumption perhaps. Around town and general mix of highway as much as possible the onboard computer is 10.5 plus ish so figure that was just normal with car and alloy bullbar. No different to anyone else posting either tuned or not.

Most interesting, especially tyre pressures, mine I'll solo at 38 all round but towing front will go to 40 and rear 45 with the van at 47 (265 75R16) and they all end up 4-5 psi higher ............. One thing I have noticed over time is depending what grade of oil Im using seems to have a bearing on the fuel economy...
Having put my Grand over the scales when its in town mode, full tank and 2 bums on seat there is only 340kgs left till I'm at GVM, most concerning really... alloy bar, SS bash plates, tow bar, side steps, LT tyres, tool box etc account for the rest of load cap, I did some weights and measure on the gear and it surprised me how quickly it gets eaten up..............

[Mousie]

I had to remove all factory bash plates and QT told me okay to temporarily remove the 1/3 rear seat. Steel to alloy wheel and left the cargo floor behind just to get under by a few kilo. Only have alloy bull bar and tow bar but 45kg extra on air suspension unfortunately. I hardly ever connect the DC cable to van given how sensitive the alt is to overloading as well. Not sure if that has any overall effect on consumption either that we would real world notice though. What surprised me is the ball weight from the point of view of handling so I found that that a variance of 30kg on ball weight. say 240 up to 270kg is a significant difference in handling feel. i.e a 240 fees just sure footed yet at 270 you have to be extra mindful of the van working you over a tad on less forgiving roads. I guess another way of saying the 30 kilo scale is non linear here in careful factor.

[drover]

Yeah, know exactly what you mean, Ive gone to a single 120ah lithium when the 2 GELs crapped out, big saving, I have also found while I don't really need a WDH as Ive upgraded my suspension I still use it but with just a small amount of tension as it makes the whole rig more stable on not so stable roads........... Run with front water tank near full other one empty keeps load nice and handles better, my set up doesn't have any power feed to van other than a direct run to fridge, batteries all juiced by solar..............
Ive been going to get my van replated to give it another couple of hundred kgs of ATM just so I can keep in the clear, just have to get around tuit ..... have plenty of lee way with the axle and chassis rating just have to book it in and pay the monies.... If just running around town mine will go over on the front with half a tank of fuel so not much leeway on front axle weights in the diesel. bar and plates are 65kg.... In the meantime stay off the Bruce Hwy..............


It's surprising the weight difference between tyre sizes and rim weights, just changing tyres from factory can add 6 kg especially into an LT ATR.