MN triton - Fuel economy issues

[Mark7792]

G'day Gents,

I have just chucked on a set of 265x75R16 muddies to my auto MN triton.

The tyres have seen my fuel economy jump by a staggering 5L per 100Klm

I am now getting 15L per 100Klm instead of 10.5L per 100Klm pre tyre change.

The ute has an Xrox Bullbar and 2 inch lift. and im about to fit a winch however my current fuel usage has put that into question.

Is this normal or is there a possible issue causing my excessive fuel consumption. I am just about out of ideas as a possible fix and im hoping this is a fault that can be fixed rather then a modification reprocussion.

Thanks again

[macca002]

I have 265's MT's and an Xrox and dual battery and my economy jumped about 2lt per 100km.
I am still running the factory alloys though.

Around town seems to have soaked up the most increase, on the highway the economy jumps back down to almost factory.

Have you done a highway run to see if the economy is still poor? MT's are heavy tyres and if you are running steel rims are heavier again. This is a lot of mass to rotate, and if you are stop starting a heap I can see where the increase comes from.

Out of all the 4x4s I have owned, an increase in tyres seems to have the biggest impact on economy.

[siwren]

Hi Mate,

I have a MN Auto GLXR (is yours a GLXR?) and get 16.5L in the city. In truth this is pretty much grinding inner city traffic and never above 60kmh. When calculating it at the pump I recently got 736Km for 106L, or 14.4L per 100km. If you factor the fact that bigger tyres mean it actually went a little bit further than the odometer, it could be 14L/100km in my example.

I have 265/65/R17 All Terrains, bullbar, canopy, rack, long range tank, etc, etc. I'd suggest the muddies are worse than my all terrains for economy.

However, I've only got 2400km on the clock and it apparently should get better with more KM's. But its been bad from the very beginning where I was only getting 380-400km out of the 75 litre tank, before tyres and accessories.

It been to the dealer twice and they've uploaded new firmware twice, however I only received the latest firmware (apparently 2 weeks old and designed to resolved fuel economy issue apparently) for a few days so not enough time to determine whether its made an impact.

I'm going the be doing another 3000 km in the next week, so this should give a better idea of Hwy usage at 110kmh.

But in short I think that if you have an MN Auto and mods its not great fuel wise.

The other way I look at it: I paid $36k for the GLXR new. Thats a lot cheaper than the equivalent other brands. So the difference in price offsets the slightly higher usage and you still end up ahead in my mind. Or thats what I tell myself to feel better.

Simon

[odie602r]

5L does seem a huge increase, considering a 265 tyre isn't a massive increase in size over stock.

As someone else said, is the fuel economy differences comparing apples with apples? That is, over same roads or conditions?

I just remember early on comparing two highway runs - one before then one after a mod - that showed an increase in fuel usage, then realising some time later that one highway run was through hill terrain and the other flat roads

[Cowboy Dave]

What pressures are you running? Maybe try a bit higher/harder and see what difference it makes.

[Calblitzen]

I run 265/75R16 AT's with steel bullbar, canopy, roof racks, triple battery setup,some tools and yes it's a manual. I also do alot of city driving and normally return 10.5L/100, however since the 30k service I'm getting below 10L/100 and that is calculated at the pump and adjusted by 6% to allow for the larger tyres.

[Mark7792]

I do not do a whole lot of city driving - about 50klm a day early morning run and a rather late one home so i dont see the general start stop of the city. I havent compared it on the highway yet, ill have to give it a whirl and see. My primary concern is that i use the triton as a Towing vehicle as well and have been in the process of organising a trip up north and am now worried about the fuel usage with an extra half tonne on the rear end.

I will check the tyre pressure thisafternoon and get back to you, i havent looked at it since install.

It seems the autos cant keep up to the manuals in terms of performance.

I was considering swapping out the stock exhaust for a 3 inch and speaking with a diesel performance chip company to see if any benefit could be gained from continual modification.

[Mark7792]

Hi Mate,

I have a MN Auto GLXR (is yours a GLXR?) and get 16.5L in the city. In truth this is pretty much grinding inner city traffic and never above 60kmh. When calculating it at the pump I recently got 736Km for 106L, or 14.4L per 100km. If you factor the fact that bigger tyres mean it actually went a little bit further than the odometer, it could be 14L/100km in my example.

I have 265/65/R17 All Terrains, bullbar, canopy, rack, long range tank, etc, etc. I'd suggest the muddies are worse than my all terrains for economy.

However, I've only got 2400km on the clock and it apparently should get better with more KM's. But its been bad from the very beginning where I was only getting 380-400km out of the 75 litre tank, before tyres and accessories.

It been to the dealer twice and they've uploaded new firmware twice, however I only received the latest firmware (apparently 2 weeks old and designed to resolved fuel economy issue apparently) for a few days so not enough time to determine whether its made an impact.

I'm going the be doing another 3000 km in the next week, so this should give a better idea of Hwy usage at 110kmh.

But in short I think that if you have an MN Auto and mods its not great fuel wise.

The other way I look at it: I paid $36k for the GLXR new. Thats a lot cheaper than the equivalent other brands. So the difference in price offsets the slightly higher usage and you still end up ahead in my mind. Or thats what I tell myself to feel better.

Simon

Yes it is a GLX-R

[siwren]

It seems the autos cant keep up to the manuals in terms of performance.

I was considering swapping out the stock exhaust for a 3 inch and speaking with a diesel performance chip company to see if any benefit could be gained from continual modification.

To me the Auto seems very soft if that is a term that can be used, it almost feels like a CVT gearbox sometimes where speed increases but revs remain the same like the torque converter was catching up with the engine. I wouldn't be surprised if it sucked up power compared to similar 5 speed gearboxes.

With the new ChipIT chips becoming available, I'll be going down the mod path to get better fuel economy. Comments by others here seem to suggest it makes a decent improvement.

[hvac guy]

Change diff ratios maybe or don't run that size tire day too day

[Duck]

That sounds a bit fishy to me a 50% INCREASE for tyres No doubt the larger tyres increase it's consumption but not by 50%. Maybe give it a good highway run & do a check at the pump & if it's still shocking I would be hitting up the dealer to do some further investigation. Good luck

[dan_4818]

I average about 400kms from normally around 68-70 litres. Canopy lift muddies and draw system with camp gear in (doesn't leave the car). An chip it chip aswell.
Doesn't matter if its highway or town driving. Get better mileage town driving. As soon as I go over 90km an hour that's when it really starts to chew the juice

[AussieTriton]

WOW! That kind of fuel usage sucks. I have a brand new 2013 MN Dual cab manual, and although it only has 1100 km on it, my first tankful netted me 760 km for 70 litres. I/m almost half way through the second tankful and looks like I'm on target for another 700+ km. I don't baby it, but I don't drag race around either, I just stay within the speed limits and drive sensibly. I dont have a lift (don't really want one yet), no MT's, bullbar, canopy, etc. I will be going to Hankook's AT-M in 255 whatevers to enhance traction offroad, and looking for an appropriate bullbar.
Might I suggest you dump the roof rack, and empty out any gear you dont need to be carrying everyday? Roofracks are bad for wind resistance and can cost you several MPG's, along with extra weight you haul around. Just my $0.02.

[har05l]

WOW! That kind of fuel usage sucks. I have a brand new 2013 MN Dual cab manual, and although it only has 1100 km on it, my first tankful netted me 760 km for 70 litres. I/m almost half way through the second tankful and looks like I'm on target for another 700+ km. I don't baby it, but I don't drag race around either, I just stay within the speed limits and drive sensibly. I dont have a lift (don't really want one yet), no MT's, bullbar, canopy, etc. I will be going to Hankook's AT-M in 255 whatevers to enhance traction offroad, and looking for an appropriate bullbar.
Might I suggest you dump the roof rack, and empty out any gear you dont need to be carrying everyday? Roofracks are bad for wind resistance and can cost you several MPG's, along with extra weight you haul around. Just my $0.02.

Just about everyone will get these figures from new, I know I did

What people need to understand is once you change the tyre diameter and add a few mods they'll go out the window. I manage 550ish now and just fill the thing up again

[Mudme]

All I have planned for mine is 265's a winch bar and winch and a suspension lift, I can't see it changing the fuel Econ too much

[AussieTriton]

WOW! That kind of fuel usage sucks. I have a brand new 2013 MN Dual cab manual, and although it only has 1100 km on it, my first tankful netted me 760 km for 70 litres. I/m almost half way through the second tankful and looks like I'm on target for another 700+ km. I don't baby it, but I don't drag race around either, I just stay within the speed limits and drive sensibly. I dont have a lift (don't really want one yet), no MT's, bullbar, canopy, etc. I will be going to Hankook's AT-M in 255 whatevers to enhance traction offroad, and looking for an appropriate bullbar.
Might I suggest you dump the roof rack, and empty out any gear you dont need to be carrying everyday? Roofracks are bad for wind resistance and can cost you several MPG's, along with extra weight you haul around. Just my $0.02.

Just about everyone will get these figures from new, I know I did

What people need to understand is once you change the tyre diameter and add a few mods they'll go out the window. I manage 550ish now and just fill the thing up again

Thats why I'm sticking to the 255 dia, its very close to original and wont hurt my economy too much. I dont plan on adding too much additional weight with accessories, either, I'll lose the weight carrying capacity.

[Dingo Dog]

Hi
Just did my first set of fuel figures today. 2013 MN stock. 781 km for 63.3 litres. That works out to 12.33 km per litre or 8.1 litres per 100km. Mixture of city/country about 80/20 atm.
1700 km on the clock.
I'm happy with that so far but small mods to come in future , I am going to watch what happens as each mod goes on over the next 6 months.

[AussieTriton]

Hi
I'm happy with that so far but small mods to come in future , I am going to watch what happens as each mod goes on over the next 6 months.

Thats basicly what I'm going to do. My mileage is all stop/start city only, havent had a chance to do any highway mileage yet but I will.

[triton08]

ok I guys I drive 2008 ml with LR tank 225's and canopy bullbar dual battery roof racks with ladder camping and tools and supplies for work throughout the NT and we have speed limit of 130 on open roads any way sitting on 120k/hr I get 10l per 100km and that is about average also the vehicle has 65000 on the odometer.
70% of driving is on heavy corrugated country dirt roads .

[macca002]

Do you have a snorkel? Maybe this is the problem?
http://www2.pajeroclub.com.au/forum/sho ... hp?t=15278

I have a snorkel though and get about 10lt/100 on the highway so I do not know if the above is true or not - just a suggestion

[hvac guy]

I've tried both ways on mine and found high fuel use with it backwards
Have herd of this issue with non turbo cars but.

[wrightyo_17]

I am getting around 15.5ltrs per 100 with cruise control on at 110kms.. iv got steel bulbar side bars, rear bar, canopy and roof racks, 265/75/16 mickey atzs on 16/8 steel rims... is this a bit high?? as iv only done 35,000kms???

[Orl247]

Have you got an exhaust made about 3l per a hundred difference to my economy but I have just put 245/70 17 km2s on and it put the speedo to dead accurate and the read out has gone up about 2 to 3l per hundred about to take it on a highway run next week and see what it's like

[siwren]

Mark, are you going off the trip computer or doing a manual calculation?

So I managed to take my truck on a long run up to Brisbane and back. Averaged 11L/100Km on the way up (Pacific Hwy) and 10.8L/100Km on the way (NE Hwy). If you factor in the bigger tyres this goes to 10.6 up and 10.5 down. This was doing the speed limit at all times and keeping up the speed going up hills.

However the above numbers are calculated via fuel/distance traveled. The trip computer showed 13.1 for the trip up and 12.8 for the trip down. So the trip computer has no idea.

So it looks like the latest firmware has made a difference in all aspects too, and I'm happy with the above numbers given the additions and rack acting like a giant wing. With the bigger tank a can get nearly 1100 hwy km's.
Will monitor the fuel usage around town with the new firmware.

[Pom10]

Hi I have just returned From a trip to darwin and back nearly 12k round trip approx ,1k of dirty road fuly loaded no room left to put any thing else in the truck,
And averaged around 9.7 per 100 k running 265 ,75 ,16 (hancook s ATMs ) these tyres preformed very well and with no problems,
3 adult 2 kids ,Canopy iron man bulbar second battery ,snorkle
worst fuel was 12.65 per 100 k ( this was when I dropped the pressure on very bad corragations and mud and dirt
Best fuel was when my son was driving (on his L plates sitting on around 80to 90 ks which averaged around 8,8 k per 100 ks) on the hwy
Was very surprised on who good the fuel economy was for the trip ( only hiccup was I filled up in mount isa with petrol,luckily never started the truck and the racq came and saved the day (emptied the tank and on the way by lunch time )
Chees
Pom10