2.7lt TDV6 fuel economy change

[AnD3rew]

Hi all

I used to get fuel economy as reported on the dash of high 9's on highway cycle and low 10's getting up it around town.

Since I did my build up, rhino short rack, Foxwing, front ARB bar with winch, RWC and long ranger tank, safari snorkel, I can't get it under 11.7 even on highway cycle.

I expected it to go up a bit but that seems quite a lot. What are Ther people with similar set ups getting?

Do you think I might be confusing the computer by topping up from my LR tank while driving or is something else wrong?

[coolum]

Sounds like you have punched an even bigger hole in the 'air' and you may have to pay for it.

bullbar turbulence may save you from a roo but not the bowser.

not trying to be a smarty .. but when I drive my W/E'er sports car (at speed) with the rear view mirrors folded in, its so much quieter, that i figure the noise is doing something.

I shudder when I see Patrols with big lift, monster tyres, Bullbar, Snorkel, Monster rack with a tinnie and a 23' caravan (= gallons per mile).. and I think the stock V8 D3 drinks a bit ??

Don't know about low speed though? maybe thats where the extra wieght kicks in ?

again not trying to get offside here .. I love all the info the Aulro site has, its a special forum and there's so much to be learn't browsing the threads..

...sorry if this (comment) is not considered constructiive

Coolum

[101RRS]

You don't think all that extra drag and weight will not have an impact on fuel economy. I would say the changes you have experienced are to be expected.

Garry

[Disco4SE]

Maybe purchase an ecu upgrade to compensate for the extra weight.
You will be surprised how much extra weight you have added. Has to have a fair impact on your fuel economy.

Cheers, Craig

[AGRO]

I have similar "touring" build, less the awning. I seem to always get around 10l/100km out on the big road. But I only cruise at 100km/hr. Fuel consumption is about 12l/100km when travelling at 110km/hr.

[AnD3rew]

If you read my original post I said I expected it to go up, and I am not complaining I am very happy with my mods and am using them for what they were intended for so if a couple of liters per 100 is the price I can live with it.

My question is just to try and see if this is the normal to be expected or if there might be another problem.

Thanks Agro, that's helpful to know.

[AnD3rew]

Maybe purchase an ecu upgrade to compensate for the extra weight.
You will be surprised how much extra weight you have added. Has to have a fair impact on your fuel economy.

Cheers, Craig

Not surprised at the weight, I know pretty much exactly how much it is. I am wary of ECU upgrades, I know lots have done it but I never quite trust that it wont accelerate the end of turbo's and the onset of other issues. I am still very happy with the power so would only consider it for the economy.

[Tombie]

I just don't understand how 10l/100 ever became the magic number :)

12 isn't a lot...

As for your kit...

Take the fox wing and rack off during normal use. No need to have it out in the elements for no reason and will remove the drag issue.

The rest, should see you down around 10.5-11l

Snorkels can use a bit more than without.

[scarry]

I am flat out getting much less than 11's with two roof rails,and nothing else.
So i would say what you are getting is to be expected.

If you are going by the dash read out you may be in for a surprise as it is usually optimistic by around 10% at least.

Calculating the actual l/100k's is the only way to get a true reading.

[Graeme]

Snorkels can use a bit more than without.The D3/4 snorkel blocks a lot of airflow from the windscreen judging by the wind noise it creates.

[AnD3rew]

I just don't understand how 10l/100 ever became the magic number :)

12 isn't a lot...

As for your kit...

Take the fox wing and rack off during normal use. No need to have it out in the elements for no reason and will remove the drag issue.

The rest, should see you down around 10.5-11l

Snorkels can use a bit more than without.

Will take the Foxwing off, but with the cargo barrier in it is handy to have the rack on for longer stuff from Bunnings:p

Also don't really have anywhere to store the rack and its a pain to take it on and off.

I wasn't surprised it went up, just didn't expect it to be quite that much but as I said not really worried as long as that's all it is.

[WhiteD3]

Not surprised by those numbers. With a clean roof I get 10.x around town and 8 on the hwy. 2 bars and a Rhino basket on the roof adds 1 to 1.5 onto this.

[Disco4SE]

Not surprised at the weight, I know pretty much exactly how much it is. I am wary of ECU upgrades, I know lots have done it but I never quite trust that it wont accelerate the end of turbo's and the onset of other issues. I am still very happy with the power so would only consider it for the economy.
Providing that you have it done by a reputable source, there wont be any problems.
I had my D3 2.7 done by Ritters Landrover in Melbourne. Was very happy.
Even saw this on the dash at one stage....
https://www.aulro.com/afvb/images/imported/2013/04/901.jpg

Cheers, Craig

[TerryO]

The numbers you quote Andrew are about right with those mods, as Tombie says take the stuff off the roof and it will be better.

I recently took the STT's off and refitted the AT3's with roughly the same rolling circumference and the economy improved around 1.5 litres per hundred.

[discojools]

Andrew,
Might be worth making sure your intercooler hose hasn't perished. This can cause increased consumption and a slight lack of performance. Happened to me with my previous D3 and I blamed it on the extra stuff I had added.
Since adding a bar, snorkel and winch to my D4 2.7 consumption doesn't seem to have changed..about 8.4 displayed (which is in reality about 9) at 110 kph.
I am sure it will suffer when I mount my new Rhino platform rack and roof tent. Be interesting to see by how much.

[101RRS]

https://www.aulro.com/afvb/images/imported/2013/04/901.jpg

Cheers, Craig

I have seen those numbers as well - very satisfying.

Of more interest of me in this pic though is how to do get the time to display in the top left corner?? Mine only displays (when selected) on the bottom display which then replaces the fuel consumption figures etc.

Cheers

Garry

[sheerluck]

I have seen those numbers as well - very satisfying.

Of more interest of me in this pic though is how to do get the time to display in the top left corner?? Mine only displays (when selected) on the bottom display which then replaces the fuel consumption figures etc.

Cheers

Garry

I believe your friendly local Faultmate owner can do that, though it depends on your model year and software version.

(Source - reading a lot of posts on Disco3)

[AnD3rew]

Providing that you have it done by a reputable source, there wont be any problems.
I had my D3 2.7 done by Ritters Landrover in Melbourne. Was very happy.
Even saw this on the dash at one stage....
http://www.aulro.com/afvb/members/disco4se-albums-my+disco+4-picture4317-004-2.jpg

Cheers, Craig

That is a nice set of figures

[Disco4SE]

Of more interest of me in this pic though is how to do get the time to display in the top left corner?? Mine only displays (when selected) on the bottom display which then replaces the fuel consumption figures etc.
It was like that when I bought it Garry. Bought it as a demo.

Cheers, Craig

[101RRS]

Thanks - that is not standard and as mentioned must have been turned on at some stage.

Garry

[AnD3rew]

My time displays there and did from new, I haven't added it.

[101RRS]

D3 or D4??

[AnD3rew]

Mines D3

[jonesy63]

Time on the dash was a feature of the MY07-on D3. I had it on my MY07 D3.

[101RRS]

Not on my 07MY RRS.

Garry

[jonesy63]

I also lost that feature - when I changed to aftermarket stereo.

[101RRS]

That is a different issue as you loose the time irrespective where it is displayed on the command display.

[TerryO]

Not on my 07MY RRS.

Garry


Just further proof that even a old D3 is a superior vehicle to a RRS ...:angel:

[PeterOZ]

and $50k cheaper!!! :D

FWIW my clock is in the top LHS of the display too MY08 D3 TDV6 ....

6km/100 mmmm I wish! I was considering an ECU upgrade, forget who through but it wa one where you plugged the gadget into the ECU port, it downloaded the current mapping and it was sent off for tweaking then came back and again plug the gadget in and it uploaded.

I did not go ahead as like others I am concerned at how it might affect the long term life of the engine and especially the turbo.

[DiscoWeb]

Andrew,

I have a 2.7 tdv6 D3 with about 90,000 on the clock.

I have a bar and winch as well as a set of steel sliders but not RWC/ long rant tank, snorkel or awning. However I always take the roof racks when not in use (mostly to fit into work parking).

Since I fitted the bar and winch the fuel consumption has gone up by around 0.5 - 1.0l/100km from say 8.5/9.0 to 9.0 /9.5l for highway touring. Maybe a bit more of an increase for around town 9.5/100 to 11.00/100.

So an increase to 11l/100km with some extra gear fitted sounds about right, particularly when you carriy stuff on the roof. I notice about 0.5l/100km increase whenever I put bikes on the roof for a holiday.

For day to day, strip as much off, take out any recovery gear you only need off road and keep the weight down and the profile clean.

In terms of cruising speed I generally sit around 5km above the posted limited when travelling so prefer to punch it through than sit back to conserve fuel.

Vehicle will do that all day but does push up consumption, if you really worried about it travelling around 80 -90km seems to be about the most efficient speed but I can not do that !!!

George

[TerryO]

On a slightly different topic I have noticed when towing our van that at around 80 kph the fuel consumption is dramatically better than towing at 110 kph.

How much better? By as much as 5 - 7 litres per hundred kilometres depending on the road surface and wind etc.

[Tombie]

<snip>

I have a bar and winch as well as a set of steel sliders but not RWC/ long rant tank, snorkel or awning.

<snip>

George

My long *rant* device sits inside the cabin :) Doesn't affect the wind drag...

[PeterOZ]

On a slightly different topic I have noticed when towing our van that at around 80 kph the fuel consumption is dramatically better than towing at 110 kph.

How much better? By as much as 5 - 7 litres per hundred kilometres depending on the road surface and wind etc.


stands to reason, do some basic physics velocity / force calculations.

The vehicle is operating within a fluid, air and hence fluid dynanmics come into play, as in aircraft the Reynolds number becomes critical in determing the effect of the fluid on drag.i.e moving through that fluid.

Fd=1/2.pv^2.Cd.A that is just for the drag force, then use that in the power equation to obtain various velocities.

so air drag in this case increase with the square of velocity.

But . . .

Power required to overcome this drag or Fd is given by;

Pd=Fd.V=1/2.Pv^3.A.Cd

Hence the power required to push the vehicle and overcome the drag of the air fluid increases as the cube of the velocity.

As an example if the D3 cruises on a highway at 80 km/h it might require say only 7.5 kW to overcome air drag (Cd), but the D3 at 160 km/h in this example requires 60 kW of power.

Doubling speed the drag (force) quadruples as in the formula. Exerting four times the force over a fixed distance produces four times as much work.
(Sound familiar from high school physics? :o).

At twice the speed the work (resulting in displacement over a fixed distance) gets done twice as fast. Now know that power is the rate of doing work, so four times the work done in half the time requires eight times the power. We have not factored in the rolling resistance in relation to the drag force in this either . . .

Bottom line you pay at the bowser for all your goodies and your right foot. :cool:

sorry guys geek in me having fun.

[Tombie]

On a risk vs saving basis though...

Flowing at 100km/h means minimal interaction with large road users and minimizing of risk.

Driving at 80km/h to save a few $$$ could (and has) cost people a lot more!

Add in fatigue, driver frustration and impatience and you have all the makings of a disaster.


I often get on this soapbox, but have witnessed so many close calls, and a few that ended up fatal that this is just not a good scenario.

[jon3950]

My long *rant* device sits inside the cabin :) Doesn't affect the wind drag...

I've kept the same one I had fitted to my first Disco. Still going strong, always been easy to fit to each new Disco and besides, you don't get much for them second hand.

[AnD3rew]

I've kept the same one I had fitted to my first Disco. Still going strong, always been easy to fit to each new Disco and besides, you don't get much for them second hand.

:Rolling:

Agreed, I have had the same one fitted to 3 Disco's as well as 2 Suzukis' 1 Pajero, 3 commodores and 2 Falcons. Still going strong, a bit worn around the edges but all functions still operable.

[jon3950]

My only complaint is it seems to be getting noisier with age.

[scarry]

I've kept the same one I had fitted to my first Disco. Still going strong, always been easy to fit to each new Disco and besides, you don't get much for them second hand.

And i have the issue where it is hard to extract it from the drivers seat.....

I have to drive the ****box van all week,then comes the weekend and i am relegated to the passengers seat:(:p

[Steve223]

With all my moods I'm around the 13l mark on average, drover the second D3 one week without a remap and what a change it makes for me remap or ecu upgrade is a necessity as it makes such a big difference

[PeterOZ]

sounds familiar, had a fair bit of work done to mine and now SWMBO likes driving it, well she always did! Now I am mainly driving the Lancer to work :eek::censored:

Landrover dear, not lancer .....

think I need to buy her that little convertible she has her heart set on then I will get the D3 back again lol!! :cool: