Standard tyre size, calcs are right - if you can't improve it, I would be wondering if one of the sensors is providing a bad response, like the MAFS or boost pressure sensor.
D40 chewing excessive fuel?
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K
KraftyPg
Guest
Not that it will change things much but how accurate is your odometer? I know mine is the same 9% out that the speedo is which means my kilometers per tank need to be adjusted from what the odo reads but not everyone else here has reported the same error.
Even filling at the same servo with the same pump can vary figures because temperatures and climate have a bearing on the fuel delivered, again it wont be substantial but it can make a difference and many small differences could eventually add up to a significant difference eventually.
Not saying either of these are an issue to you but realistically fuel economy in current vehicles is not an exact science especially when you are working with equipment that is not exact itself.
Even filling at the same servo with the same pump can vary figures because temperatures and climate have a bearing on the fuel delivered, again it wont be substantial but it can make a difference and many small differences could eventually add up to a significant difference eventually.
Not saying either of these are an issue to you but realistically fuel economy in current vehicles is not an exact science especially when you are working with equipment that is not exact itself.
Ive done another test today. After resetting the ECU last night i filled up this morning, drove up the Hume Fwy and back to servo to fill again. 193.3 km on clock, 40km getting to and from Fwy and the rest at speed limit, 110km/h and on the weigh bridge at 2660kg. Yes ,i know dropping the speed will help but it was a test without changing too much. 24.34l to fill back up which should be 12.59l/100km. A bit better but not enough for my liking.
My spedo is out the same 9% but the odometer and trip meter is accurate (figure that one out ). Have checked them against GPS.
How do i check the sensor thingys?
How much does the roof rack change things?
Sorry if i sound like i'm a tight wad, but i'm not worried about cost it's more the distance i want to be able to travel.
Anyway, thanks for all your help so far i really appreciate it.
My spedo is out the same 9% but the odometer and trip meter is accurate (figure that one out ). Have checked them against GPS.
How do i check the sensor thingys?
How much does the roof rack change things?
Sorry if i sound like i'm a tight wad, but i'm not worried about cost it's more the distance i want to be able to travel.
Anyway, thanks for all your help so far i really appreciate it.
K
KraftyPg
Guest
There is no set figure that a roof rack will change but like a suspension lift or bigger tyres it could have an effect, especially if you tie an elephant to it.
Don't put much faith in an ECU reset being your savior either. The ECU is apparently an ever learning system so if you reset the ECU today back to factory settings but continue to drive the way you have previous it wont take long for the ECU to sense your habits and adjust accordingly. There is some chance that through changes over time the ECU may have changed its settings to use more fuel and resetting it can make a difference but realistically while it watches and learns from the way the driver operates expecting the reset to fix many issues is not realistic.
As you are driving a 2.6 tonne wind break getting 12.6LPH at 110kph I really don't see anything else that could bring down your economy than speed. It's a 5 year old engine which at best was quoted in the 11's on a test bed when it was new, I think you're doing quiet well at 12.6
Don't put much faith in an ECU reset being your savior either. The ECU is apparently an ever learning system so if you reset the ECU today back to factory settings but continue to drive the way you have previous it wont take long for the ECU to sense your habits and adjust accordingly. There is some chance that through changes over time the ECU may have changed its settings to use more fuel and resetting it can make a difference but realistically while it watches and learns from the way the driver operates expecting the reset to fix many issues is not realistic.
As you are driving a 2.6 tonne wind break getting 12.6LPH at 110kph I really don't see anything else that could bring down your economy than speed. It's a 5 year old engine which at best was quoted in the 11's on a test bed when it was new, I think you're doing quiet well at 12.6
K
KraftyPg
Guest
Just don't come back here complaining that your economy increases after the lift 
At the end of the day there is no right or wrong figure, we all drive different and we all have different set ups despite the badges being the same and those difference no matter how small can make big differences in economy figures.
At the end of the day there is no right or wrong figure, we all drive different and we all have different set ups despite the badges being the same and those difference no matter how small can make big differences in economy figures.
Haha guys, absolutely right in my experience too. 12.5-odd LPHK for a 110km/h cruise is about on the money. Do the same trip but limit yourself to 95km/h and see the difference.
Just on the speedo/odometer issue. The ECU is reading the rotations from all 4 ABS sensors and translates that into both distance travelled (total number of revolutions multiplied by the wheel's circumference) and the speed (distance per unit time). The ECU is quite accurate and the odometer is not very far off the mark on standard tyres.
The speedo is a different kettle of fish. If you query the ECU digitally (Scangauge, Torque, ECUTalk etc) you'll be surprised how accurate (on standard tyres) the ECU knows the vehicle speed. The problem actually exists in the needle. The ECU knows that for a certain speed, a certain amount of voltage has to be applied to the coil that moves the needle. That's where the inaccuracy reveals itself. I've noticed that my speedo can fluctuate as I'm driving - at one minute 60km/h (actual) is shown by the needle as 62-63km/h. The next minute, the needle is nudging 70km/h and my satellite system is still saying 60km/h!
Just on the speedo/odometer issue. The ECU is reading the rotations from all 4 ABS sensors and translates that into both distance travelled (total number of revolutions multiplied by the wheel's circumference) and the speed (distance per unit time). The ECU is quite accurate and the odometer is not very far off the mark on standard tyres.
The speedo is a different kettle of fish. If you query the ECU digitally (Scangauge, Torque, ECUTalk etc) you'll be surprised how accurate (on standard tyres) the ECU knows the vehicle speed. The problem actually exists in the needle. The ECU knows that for a certain speed, a certain amount of voltage has to be applied to the coil that moves the needle. That's where the inaccuracy reveals itself. I've noticed that my speedo can fluctuate as I'm driving - at one minute 60km/h (actual) is shown by the needle as 62-63km/h. The next minute, the needle is nudging 70km/h and my satellite system is still saying 60km/h!
joe2006
Member
Re speedo inaccuracy. It has me buggered. The speedo is different to my gps which is different to my Ultragauge. Surely one should be correct, but which one? (that's not really a question).
K
KraftyPg
Guest
I'm not sure I want to query my ECU digitally!
My odo and speedo are still out equally but the SG reads the same as a GPS.
Joe what sort of differences are you talking about? Does the ultraguage have an adjustment on it to allow for some error, I can't remember if SG has the error adjustment for all categories but I know it has for fuel and I seem to remember something about a speed correction adjustment but as mine never needed it I didn't have to look into it.
My odo and speedo are still out equally but the SG reads the same as a GPS.
Joe what sort of differences are you talking about? Does the ultraguage have an adjustment on it to allow for some error, I can't remember if SG has the error adjustment for all categories but I know it has for fuel and I seem to remember something about a speed correction adjustment but as mine never needed it I didn't have to look into it.
joe2006
Member
You can calabrate distance (presumably this will fix the speed error?) but I have to find a road with distance markers. Not sure it is worth the effort as the fuel consumption figures are what I am after and providing all the other inaccuracies result in reasonably correct consumption figures, I will be happy.
The difference between the Ultragauge & GPS is only 1kph at around 60 but can be up to 3kph at around 100.
When I replace the tyres with something a little taller, the figures will change anyway so I might worry about it then.
It is very interesting to watch the effect the right foot has on the instantaneous fuel figures and averages. Needless to say the boost & /or fuel rail figures can be monitored for the same end result. The actual numbers mean less than the direction they are heading.
The difference between the Ultragauge & GPS is only 1kph at around 60 but can be up to 3kph at around 100.
When I replace the tyres with something a little taller, the figures will change anyway so I might worry about it then.
It is very interesting to watch the effect the right foot has on the instantaneous fuel figures and averages. Needless to say the boost & /or fuel rail figures can be monitored for the same end result. The actual numbers mean less than the direction they are heading.
K
KraftyPg
Guest
Calibrating the distance probably will fix the speed error.
I don't know about the Ultragauge but I assume it works similar to the scangauge given that it would get it's info from the same source. SG reads the fuel usage from the ECU and therefore any distance error would not actually effect your LPH. It will effect you distance to empty or figures based on distance but not the amount of fuel the ECU knows is being pumped into each cylinder.
You ought to see the effect the right foot has on instance fuel figures when you stuff up and forget to change the tank size to 80 litres from it's factory set 15. I could easily get 300LPH readings at 95kph!
I don't know about the Ultragauge but I assume it works similar to the scangauge given that it would get it's info from the same source. SG reads the fuel usage from the ECU and therefore any distance error would not actually effect your LPH. It will effect you distance to empty or figures based on distance but not the amount of fuel the ECU knows is being pumped into each cylinder.
You ought to see the effect the right foot has on instance fuel figures when you stuff up and forget to change the tank size to 80 litres from it's factory set 15. I could easily get 300LPH readings at 95kph!
joe2006
Member
These types of gauges are great if your monitoring your fuel use and can effectively teach you to drive economically. Sometimes you don't even realise what you are doing can have a negative effect.
Even going up an incline need not have an impact on consumption if you are prepared to take a hit on speed. Didn't realise that until the other day.
Just hope it's not a matter of becoming obsessed.
Even going up an incline need not have an impact on consumption if you are prepared to take a hit on speed. Didn't realise that until the other day.
Just hope it's not a matter of becoming obsessed.
K
KraftyPg
Guest
That's exactly right joe and it's why when people say "I'm an economical driver" it's no real indication of anything, but thankfully the number of people getting offended when it's pointed out to them that their idea of economical is different to others is getting less.
I don't obsess about my economy but the one thing I have noticed with the Nav over my other cars is that I can constantly return better than average (this site's average for 09 auto's) because I spent a few months watching the SG and letting it teach me. Now days my driving habits have changed to the point that I don't need to constantly watch the SG because I can feel what the car is doing. However that's not to say I don't still make the same foot movements as others from time to time, I'm just more aware of them than some people.
I don't obsess about my economy but the one thing I have noticed with the Nav over my other cars is that I can constantly return better than average (this site's average for 09 auto's) because I spent a few months watching the SG and letting it teach me. Now days my driving habits have changed to the point that I don't need to constantly watch the SG because I can feel what the car is doing. However that's not to say I don't still make the same foot movements as others from time to time, I'm just more aware of them than some people.
K
KraftyPg
Guest
You can buy them from Ample Outdoors, but they only have a shop in either NSW or QLD.
There might be someone else in Aus that sells them from a store front but I don't remember who it was I saw advertising them.
Succumb to the power of thy gadget!!
There might be someone else in Aus that sells them from a store front but I don't remember who it was I saw advertising them.
Succumb to the power of thy gadget!!
