Fuel economy

[TRIGLXR]

Dragging the van I average 14.5, and always at the speed limit (never below)

[Buzzy]

Just calculated my last tank of juice.
10.88L/100
Very happy with that considering its also turning 33" tyres

[sierra]

Buzzy,

From the pics it looks like you have those tyres on the original 7'' rims. I've been looking at what would fit the 6'' steel rims and 235/75 was the biggest they would take but the same site lists 8'' to 10.5'' for those tyres you run.
If you can get away with that? then the 6'' should take the 245/70/16 which would just fit under the wheel arches[2mm] with the 8mm bigger offset the steels have instead of hanging out by 6mm with the alloys.
They list 6.5'' to 9'' for the 245/70/16 so only pushing it by 1/2''.

Did your 10.88L/100km include the x 0.9 calc. for the extra tyre diameter or was it really 9.8L/100km?

[Buzzy]

Approved rim size for 285x75x16's for the MTZ's are 7-9 inch see here Mickey Thompson MTZ's
Go to the ATZ's and it goes to 7.5 inch min

What brand/sort of tyres are you after?

That 10.88 did not include the 0.9 calc for the tyre diameter

[Buzzy]

What about 235x85x16's they will fit a 6" rim. 806mm dia
The new BFG muddies come in this size

[sierra]

This was the site I was looking at.

http://www.wheelsmaster.com/rt_specs.jsp

Maybe they design those tyres to fit the narrower rim and the market, surely there are set standards for what fits or you would like to think so?

I looked at buying those GLX-R 17'' rims and tyres last week but the 6mm outside the arch without spats and the thought that the alloys would look a bit wrong on the cab chassis put me off.
I'm not after any specific brand, just want to know what fits so I can watch for a good buy in the future.

[sierra]

What about 235x85x16's they will fit a 6" rim. 806mm dia
The new BFG muddies come in this size

I need road tyres cos it's a 4x2 and unsealed roads will be it's biggest adventure.
I saw the same model with 225/75/16 tyres on the original rims the other day and it transformed the look. 235/75 or 245/70 would satisfy my ego and the latter is more likely to come up as good s/h buy.

[daryn]

Well my economy has started going through the roof, I am using the car computer to calculate at present, but am currently doing a run and will manually calculate:

08 MY09 Auto 3.2

Trip to Brisbane return - Highway sitting on 110/115km/hr
10.0l per 100k

Around the Suburbs to work and back
Before any changes 11.0 to 12.5 l per 100k
DP Chip installed 12.5 to 13.5l per 100k - I expected this at first whilst I enjoyed the new power
Tyre's changed to 265r75/17 MT ATZ 4 Rib - 13.5l to 14.5l per 100k easy
EGR blocked currently sitting on 15.9l per 100k, and I am concentrating really hard on driving as conservatively as possible.
This drive is stop start and a short 15 minute drive if that.

When I do a longer town drive with long 80k stretches it drops down to maybe 14.5l/100k

So I will know more after I do a fill tomorrow afternoon, and Wednesday morning I am driving to Sydney and back, so lots of freeway at 110/115km/hr. I will use my head to calculate this out.

I would have hoped that the DP Chip and ERG would certainly have compensated for the 265/s, maybe its also the extra load up front with Bar and winch added too which is knocking it back.

[Buzzy]

Should be getting better than that daryn
On your next run calculate it yourself and see where you are

[snowman]

Well my economy has started going through the roof, I am using the car computer to calculate at present, but am currently doing a run and will manually calculate:
08 MY09 Auto 3.2
Trip to Brisbane return - Highway sitting on 110/115km/hr
10.0l per 100k
Around the Suburbs to work and back
Before any changes 11.0 to 12.5 l per 100k
DP Chip installed 12.5 to 13.5l per 100k - I expected this at first whilst I enjoyed the new power
Tyre's changed to 265r75/17 MT ATZ 4 Rib - 13.5l to 14.5l per 100k easy
EGR blocked currently sitting on 15.9l per 100k, and I am concentrating really hard on driving as conservatively as possible.
This drive is stop start and a short 15 minute drive if that.
When I do a longer town drive with long 80k stretches it drops down to maybe 14.5l/100k
So I will know more after I do a fill tomorrow afternoon, and Wednesday morning I am driving to Sydney and back, so lots of freeway at 110/115km/hr. I will use my head to calculate this out.
I would have hoped that the DP Chip and ERG would certainly have compensated for the 265/s, maybe its also the extra load up front with Bar and winch added too which is knocking it back.

Welcome to my world........although I think yours is worse than mine
Look…. you can’t add bars, bigger tyres, and all that stuff and expect no worse consumption. (i don’t have a chip yet or blocked EGR). However when blokes in manuals are towing CARAVANS and getting about 13's, then I'm feeling a bit peeved.

My suspect is the auto not locking in at lower RPM. Do this test - when on the freeway and you have some space get to about 2400+RPM in top gear and GENTLY push the throttle down - you will see no change in RPM via the torque converter, eventually it will downshift.
Do the same thing at 1800-2000 RPM and you will see the RPM increase (without dropping a gear) which is the engine slipping in the TC. I am not sure how the gearbox is spec’d for it to 'lock in' once it is not under load (like say a Landcruiser or many other cars do). I think the tyres just make it far worse by reducing the RPM at any given speed. CCM made me aware of this on his dyno posts saying it did not lock up until about 2400RPM which I can understand under hard acceleration but not when ‘cruising’ as all that energy is going straight to the auto oil cooler!.
I did a straight high speed trip from Canberra to Sydney one night at almost nothing under 115klms (on GPS) and my economy was excellent at 9.46 l/100!! Now it was filled at Queanbeyan and refilled immediate after the Hume/M7/M4 so it was almost exclusively 115klm + but this is with the 265/70/17 Mud Terrains, barwork, aerials, canopy etc so it can be done! Temp was a nice 10 degrees or so in early evening. On the trip down with STANADRD tyres I only got 11.0 l/100 – so I am buggered if I know!
I will say this though I also changed my oil to a Nulon 15-40 (not synthetic) and my average has dropped at least 1l/100klms. i just did a tank at 11.49klms but the one before was 12.8 l/100 so it is up and down like a yoyo
Sorry for the long post – but its important, to me

[snowman]

thought i would post this for anyone interested or who has some ideas.

ML MY09 (08 build) 3.2did auto - ARB bar, rear step, razorback, side rails and steps, MT MTZ 265/70/17, baysie plates.

[sierra]

thought i would post this for anyone interested or who has some ideas.

I've read plenty of articles where auto transmissions are modified for performance applications.
Couldn't you find a good transmission specialist that can lower the lock up point to about 1,600rpm? I've driven a Toyota Surf 4 speed auto, 3L TD which locked up at 82kph in 4th and pulled 2,000rpm at 100kph. So that's 1,640rpm at lock up.
It's a very valid point because once it's locked the economy has to be the same as the manual, maybe better because it might be geared a touch higher and economy is much better with more throttle at low revs than less throttle at high revs.

First article, 'fuel smart'.
http://autospeed.com/cms/A_111510/article.html

Assuming the above article also applies to turbo diesels?

[daryn]

So Snowman and Sierra are you saying that because of my better performing mods for making it run better the transmission is maybe making me use more fuel.

I also forgot to add that I have Unifilter and clean it every 5000k, I am about to do a oil change.

[patto]

IM in your boat snow man with my TD auto running all the gear and 265/75/17.

But i have just taken ownership of a TD manual for my company - its all standard went for a run to mudgee on the weekend and it also got no where near the consumption that some of you are getting. 590km to the tank.

[snowman]

sierra,

yes my thinking exactly. i have not made enquiries yet and anyone in the sydney area who knows a sharp auto tranny specialist please post or pm me.

the thing is, i want to know why SOME autos (yes even with the bigger tyres) ARE getting better mileage. if we were all doing it this bad there there is a design flaw. if only some of us are then i think it is build flaw (defect). you cant tell me almost 18l/100 is normal to tow a single axle trailer boat on basically the F3 freeway!

for months now i have been trying to work this out because there is 'suspicion' that there may be some flaw in the new autos and some work being done by MMAL. it may just be a software issue (?) and an easy warranty fix. again anyone with info please post here (Patto was the first to indicate some issues here)

but first i have to try and identify the possible fix, then convince the dealer to listen to me (they didn't want to know about it - big tyres bars etc.). i dont want to pay an auto specialist probably good money to fix something that is arguably a warranty issue - but i will if i have to or even can. although some people just say it is only a few litres per 100 and i worked out probably about $2000 in extra fuel over the life of the car (my ownership) it is nice to get the extra distance out of the tank and not have to fill up as often etc.
lets be honest i would probably buy the petrol which has more out of the hole grunt over the diesel if they are only getting comparable mileage figures. i have owned multiples of each and without going into full pro's and con's - bang for your buck the petrol wins, if your diesel is using equal or more fuel!

any ideas and discussion is greatly appreciated and encouraged.

[sierra]

So Snowman and Sierra are you saying that because of my better performing mods for making it run better the transmission is maybe making me use more fuel.

Only if you're using the extra performance.
Has the consumption gone up since you fitted the bull bar? Apart from the aerodynamics the airflow looks severely restricted through the radiators.
That could affect consumption by spoiling the flow of air and pressure to the cold air intake and also make the thermo couple? fan work overtime pulling the coolant temperature down to compensate for the loss of airflow through the engine bay. That would also cause higher fuel consumption with the A/C being used for the same reasons of lost efficiency through the heat exchangers.

I even redrilled my number plate and moved it up 30mm to maximise the airflow.

[sierra]

sierra,


for months now i have been trying to work this out because there is 'suspicion' that there may be some flaw in the new autos and some work being done by MMAL. it may just be a software issue (?) and an easy warranty fix. again anyone with info please post here (Patto was the first to indicate some issues here)
but first i have to try and identify the possible fix, then convince the dealer to listen to me
any ideas and discussion is greatly appreciated and encouraged.

Getting technical info frustrates me. You're right, it might be designed to lock up at 1,600rpm? in 3rd and 4th but has been faulty from new? Yes it could be in the software too. Just ask them to provide you with the answers as in what gears does it lock up in and at what rpm and/or circumstances? The Surf wont lock up until the engine temp is up for example, so it could be a fault in that area stopping it?
If they wont tell you let me know and i'll give it a go. A friend of the family is a mitsubishi service advisor, distant friend though.

[sam]

There was a thread on the Pajeroclub forum some time back about the auto Paj's and bigger tyres and the issue of the T/converter not locking in .
Our new ute has only got approx 430 Km on it atm but is doing great mileage trip comp says 8.8 and going by the fuel gauge if it's anything like the old one it's easily doing that
Also what sierra said re the bull bars is a valid point hence why I took to our first one with a couple of diff size hole saws to improve air flow.
Also once you start adding more and more weight eg; bull bar , rock sliders, rear step towbar, big wheels, canopy etc etc etc then the autos T/C will not lock up so early whereas this is not an issue for the manual and this is most likely/maybe why snowman got good economy at the higher speed in good conditions as the T/C had locked in

[patto]

Guys the auto's are a 3 speed, + over drive.. My truck however feels as if it is a 4 speed + over drive.

When pulling up a hill and over drive is on it seems as if the cars drops out of Over drive and back to drive. However you click the OD button it drops back to drive, meaning that the initial drop im feeling is the actual Torque Convertor locking up.

There is definately a problem there with the Box, but Mitsubishi are not letting on with anything.

[sierra]

Just rang up a service advisor and the 3.2 has lock up in 3rd and 4th but it's all driven by software unlike the Surf that stays locked until you give it enough that it kicks down a gear. The Triton lock up varies according to throttle and locks up at very low rpm at very light throttle and the lock up rpm point increases with increased throttle even to the point that there's no lock up when you're giving it stick but not enough for kick down.
That's what he said FWIW while it's still fresh in the memory banks.
So any chip that increases the throttle across the range would likely delay lock up too and could possibly interfere more than it should? On the positive side surely it only needs the throttle input signal to the auto to be fixed at the minimum for full lock up from low rpm until kick down or decrease that signal strength to make it hold on to lock up at higher throttle and rpm?

[patto]

So would be best to see about getting this signal tweaked abit.. Because im well over this high consumption.

[daryn]

So would be best to see about getting this signal tweaked abit.. Because im well over this high consumption.

I agree.

[Homer]

Do you know if it's the same with the V6 Sierra?

[Quinny23]

Just rang up a service advisor and the 3.2 has lock up in 3rd and 4th but it's all driven by software unlike the Surf that stays locked until you give it enough that it kicks down a gear. The Triton lock up varies according to throttle and locks up at very low rpm at very light throttle and the lock up rpm point increases with increased throttle even to the point that there's no lock up when you're giving it stick but not enough for kick down.
That's what he said FWIW while it's still fresh in the memory banks.
So any chip that increases the throttle across the range would likely delay lock up too and could possibly interfere more than it should? On the positive side surely it only needs the throttle input signal to the auto to be fixed at the minimum for full lock up from low rpm until kick down or decrease that signal strength to make it hold on to lock up at higher throttle and rpm?

I dont have the answer to this but I believe your on the right track, it may also be that the auto needs to have its ecu reflashed so as to provide lock up under more load. The reason it doesnt is to provide better response under normal conditions with normal setup. For those of us with chips, xhaust and bigger tyres, we require it to lock up earlier to use the torque rather than power. I knocked of one of the sensors on my auto in the bush awhile back and it worked well at speed as the auto would lock up really quick... problem was at 60 it would jump between a locked 3rd and 4th unless under load.

So in all likely hood it can be done... just need some propella head with access to Mitsu or Toyo software parameters to relase auto ECU upgrades.

[daryn]

So I may try mine for a week without the DP - Chip to see what happens.