Power and fuel improvements

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Nav22

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Hey.
Not long ago I got a 2010 dx 2.5ltr yd25 diesel nav and looking for ways for improved the fuel economy and power.
I'm currently getting about 700km for 75ltrs and curious to see if anyone has been able to get better than that?
 
Haven't got a 2.5 but still that's not too bad I wouldn't think. With a zd30 I get between 9.5-11 litres/per hundred kilometres depending on load and driving conditions. So that's about 680-780 kms per tank. Though I drive like an old man too.

The best power mod I could think of would be to drive it to a Toyota dealer and change it for a V8 landcruiser lol.
 
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It's not just driving moderately that does it. You have to use the terrain to help (gain speed downhill, maintain - at best - speed going up hill. Stopping at traffic lights beside a Hilux will NOT help your fuel economy (stopping beside a Ssangyong or Great Wall will help, because it's hard to stop laughing and get moving). Driving above about 85km/h won't help (air resistance of a brick passing through the air reaches a point where small gains in speed require large gains in fuel consumption). Using cruise control around hills doesn't help at all, because CC is reactive to speed changes and relentless in throttle usage until it's back to the set speed.

In automatics, gentle (2000-2500rpm) takeoffs are less efficient than moderate (2500-2800rpm) takeoffs, because at the slightly higher revs you're closer to the stall speed of the torque converter therefore losing less RPM to the fluid drive. Wholesale Automatics sell a low-stall-speed TC but it's only something to consider if your TC is failing.

In manuals, keeping the RPM around 1800-2000 is best, that's where torque peaks in these engines so it's the most amount of power for the least amount of fuel. Cruising around 1800rpm (manual or auto) provides the most efficient usage.

We have a 150L tank and without towing can usually get close to 1500km on long hauls. We had 4 adults plus clothing on a trip from Newcastle to Tasmania, we drove to Melbourne, drove down to Launceston and put 120.9 litres in (1118km). Normally we don't do so well (too many Hiluxes around here, I guess).
 
Haven't got a 2.5 but still that's not too bad I wouldn't think. With a zd30 I get between 9.5-11 litres/per hundred kilometres depending on load and driving conditions. So that's about 680-780 kms per tank. Though I drive like an old man too.

The best power mod I could think of would be to drive it to a Toyota dealer and change it for a V8 landcruiser lol.
Youre not wrong about that mate. But let's be honest it pretty much is. No cup holders, no electric windows. Could pretty much be a 79 series 😂
 
I average 8.8 ltrs/100ks all day everyday, loaded tray or family in the cab. However travelling at 110 sees the numbers blow out to closer to 12ltrs/100ks. And towing up near its weight limits is gets to about 20ltrs/100ks.
I've got nearly 380k of data too, one thing that does make a difference is the tires you run, I've seen as much as 100ks per tank difference between brands.
In comparison my V10 Touareg does 11/100 regardless of load or speed, and is way more comfortable. Trouble is I can fit my tool boxes in it.
Life's little dilemmas.
 
Long time since I posted here :(

I have a similar problem.

I am getting approximately 16.3L per 100 km normal driving and 19.3L per 100 km when towing my Campertrailer :mad:

It is an auto 2010 ST D40 (Thai) dual cab carrying a decent load of kit (incl a 70L auxiliary tank) - see image below - and running 265 x 75 x R16 tyres.

I originally had a chip put on it but it didn't help with fuel economy, so I had a remap done and this was the worse mistake ever :mad:.

Fuel economy around tow went up to about 19.5L per 100 km and 22.3L when towing! - I have had it returned back to it's original tune.

I know I am carrying some weight and have slightly bigger tyres but it shouldn't be this bad - my old 80 Series had better fuel economy :(

Karl

2020-08-28 Landscape - 050-Edit.jpg
 
With the extra weight and the larger tyres you are going to struggle to get fuel economy down.

Consider the wheel as a round lever, as long as the distance from the centre of the axle to the road. The axle tries to turn the lever to push the car forward, but the weight of the vehicle (and the incline you might be on) work directly against this and the longer that lever, the more these have an impact.

It's part of the reason why I went back to standard sized tyres.

Another issue that might be in the mix - larger tyres will cause your odometer to under-read. Your wheel diameter has increased by 40.5mm, and the rolling circumference 127mm larger than standard. That should introduce an error of about 5% - so for every 100km you think you've travelled, you've done 105.

Cleaning your intercooler might help - easy to do, I've done mine a few times and all up takes about an hour. Undo the grille, remove it. Undo the hose clamps on each side of the intercooler, undo the mounting bolts, remove the intercooler. Cup one hand on one opening and pour petrol in the other. Now, turn the intercooler over, allowing the fuel to run down, and remove the hand that's going up (you'll feel the pressure building up). Turn it over a few times like this, then pour out the contents. Repeat until you start seeing normal petrol colour.

Have you blocked the EGR? The valve might be a little aged now, and allowing more exhaust gas in than is needed, resulting in more fuel being used to develop the same power.
 
With the extra weight and the larger tyres you are going to struggle to get fuel economy down.

Consider the wheel as a round lever, as long as the distance from the centre of the axle to the road. The axle tries to turn the lever to push the car forward, but the weight of the vehicle (and the incline you might be on) work directly against this and the longer that lever, the more these have an impact.

It's part of the reason why I went back to standard sized tyres.

Another issue that might be in the mix - larger tyres will cause your odometer to under-read. Your wheel diameter has increased by 40.5mm, and the rolling circumference 127mm larger than standard. That should introduce an error of about 5% - so for every 100km you think you've travelled, you've done 105.

Cleaning your intercooler might help - easy to do, I've done mine a few times and all up takes about an hour. Undo the grille, remove it. Undo the hose clamps on each side of the intercooler, undo the mounting bolts, remove the intercooler. Cup one hand on one opening and pour petrol in the other. Now, turn the intercooler over, allowing the fuel to run down, and remove the hand that's going up (you'll feel the pressure building up). Turn it over a few times like this, then pour out the contents. Repeat until you start seeing normal petrol colour.

Have you blocked the EGR? The valve might be a little aged now, and allowing more exhaust gas in than is needed, resulting in more fuel being used to develop the same power.

Thanks for that.

No I haven't blocked the EGR and might look at getting the intercooler done.

I have found that my speedo actually reads correct - what ever the speedo reads is confirmed by the GPS in my dsahcam, my tablet and my mobile phone :)

Karl
 
We've had this exact discussion before :)

The odometer and speedometer are separate devices that obtain data from the same place - the ABS rings in our car. The odometer counts wheel revolutions, multiplies them by the circumference of a standard wheel (2.398m) and provides the figures for the display.

The speedo on the other hand is a dumb beast (and you can prove this directly by having a digital display of what the ECU thinks the speed is - more on this below). The speedo takes a voltage from the ECU that varies according to speed and deflects the needle (electromagnet in a magnetic field with a spring to provide resistance) to an approximation of the speed. Some vehicles are not bad at getting this right - my wife's Ignis, and my Honda Goldwing are within 1km/h of true speed. My Navara is about 10% out (reads 110km/h at an actual 100km/h).

When I ask the ECU how fast I'm going at an actual 100km/h ... surprisingly it responds with 100km/h. So the error isn't in the ECU, or the wiring, or anything other than the amount the needle deflects against the spring in the magnetic field created by the voltage sent to it. I use an Android app called "Torque" and a ELM327 Bluetooth OBD-II adapter to get the data from the ECU.
 
The speedo takes a voltage from the ECU that varies according to speed and deflects the needle (electromagnet in a magnetic field with a spring to provide resistance) to an approximation of the speed.
the older D22's did that, but with all modern cars the speedo connects via cambuss and gets fed the actual data.
the speedo is programmed to give an incorrect read out.
i understand that this can be changed on some cars so they read correctly. also note that some cars are accurate at low speeds but inaccurate at high speeds. ie they don't do a % error like they used to.

this is partly due to making sure people don't go over speed limits (and then blame the manufacture) but also it makes people drive slower at highway speeds which saves them fuel. as fuel economy is such a big deal these days its a common tactic to make the car look like its better than it really is.
 
It is an auto 2010 ST D40 (Thai) dual cab carrying a decent load of kit (incl a 70L auxiliary tank) - see image below - and running 265 x 75 x R16 tyres.
....
I have found that my speedo actually reads correct - what ever the speedo reads is confirmed by the GPS in my dsahcam, my tablet and my mobile phone :)
That's interesting. I run the same size tyres on my 2013 Thai RX and the speedo is out by 10% across the range. I had hoped the ODBII speed would be a bit more accurate but that's out by 11% across the range. I use a GPS head-up speedo for now, at least until I can find an ODBII speedo that allows for enough correction, at an acceptable price.

My DTI chip does improve fuel economy a bit, especially on the lower of its 7 settings, even while providing more power and torque. Unlike some others on the market, it's a dual channel chip, controlling both the fuel rail pressure and the turbo boost. That's probably what makes the difference.
 
the older D22's did that, but with all modern cars the speedo connects via cambuss and gets fed the actual data.
the speedo is programmed to give an incorrect read out.
i understand that this can be changed on some cars so they read correctly. also note that some cars are accurate at low speeds but inaccurate at high speeds. ie they don't do a % error like they used to.

this is partly due to making sure people don't go over speed limits (and then blame the manufacture) but also it makes people drive slower at highway speeds which saves them fuel. as fuel economy is such a big deal these days its a common tactic to make the car look like its better than it really is.

Agreed, it's also how the manufacturers ensure compliance with ADR. Simply put, the rules state:

Speedo is NEVER allowed to read less than the actual speed
Speedo is allowed to show up to 10% + 4km/h over the actual speed.

Compliance: speedo shows 114km/h when actually doing 100.

Non-compliance: speedo shows 99km/h when actually doing 100.
Non-compliance: speedo shows 115km/h when actually doing 100.
 

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