Concerning economy!!!

[Pane]

G'day

After reading a few posts in other threads I think my d22 is using too much fuel.

It's a 2012 yd25 with bullbar ome 2 inch lift and the standard tub. It's about to go in for its 30,000 service. No engine or drivetrain mods. Stock tyres.

I normally carry about 150kgs in the tray with an empty 200 litre refueling tank and my toolbox. It's all country rd driving and I sit on about 110. Doing this week in week out I get 12.5 litres per hundred. If I sit on 90 for a whole tank it comes back to 12

I've just done a trip across to Albury carrying about 300 it's on the way over and completely empty on the way home. Sticking to 100 and not racing out the gears and it managed 11.8 for the whole trip of 480 Kay's.

I've tried inflating the tyres to 48 psi (over done I know but itwas an experiment) which resulted in 12.3 with my normal tool box and empty tank. The best I ever have gotten from it was a 11.5 going across to mildura empty on a still day sitting on 100.

After reading other posts I'm sure it's using too much fuel. The other thing I have noticed recently is its blowing a bit of black smoke on take off. I noticed this when I followed the Missus driving it.

What can I do about, what should I say to Nissan at its next service?? The fuel economy hasn't changed since new.

Cheers

 

[nakedape]

How are you measuring economy? Perhaps have a look about the forum for Old.Tony's preferred methods for this?

12.5 per hundred is a little steep -- but driving/ measuring techniques/ servicing (fuel and air filters) may influence that result.

 

[Old.Tony]

I could always post my preferred method in here!

Economy is one of those vague areas that gets really wishy-washy. Typically the D22s DO use less than you're experiencing so the first thing we'll do is make sure the calculations are as close as they can be. We do have to remember that fuel bowsers by law can be out by up to 3% and it'll ALWAYS be in the servo's favour - so if you pump in what appears to be 100L of diesel, you may have only put in 97L.

With that in mind, here's my method for calculating fuel economy.

Go to a bowser that you're going to use again and fill it until the bowser's first click. Pay for the fuel, come back to the car, reset the trip meter and drive off.

When you need to refill, return to the SAME bowser (the ground will be at the same angle, the pump has the same flow rate etc etc). Fill to the first click, pay for it and return to the car.

Now write the tripmeter value on the fuel receipt (I also write the total km down, and I still have almost all of my fuel receipts). Reset the trip meter again.

When you get home, divide the number of litres by the tripmeter value divided by 100. Example (from one of my own fills):

62.52L purchased, 520.1km travelled. 62.52/5.201 = 11.78506 LPHK.

Notice what I did with the distance travelled - I divided it by 100 just by moving the decimal point (this detail is for those who hate number crunching and want to understand it a little better).

Do that for a tank and see what numbers you get.

Now, for economy - the best economy is achieved when driving in top gear with the engine revving at around the point where the torque curve has finished its ascent and is starting to level out. That's the point where the most power is being produced for the least amount of fuel. Put in less fuel and you develop less power. Put in more fuel and you don't get as much power (it's not easy to explain in text, but when you see the torque curve that looks like a scythe on an angle, the peak is where the handle joins the head).

In the D40 YD25 peak torque is achieved around 2,000rpm which equates to around 95km/h on standard tyres (using a GPS to calculate speed, not the speedo). I am not sure about the D22, which has a different turbocharger and will have a different torque curve.

So in the D40s, cruising at around 95km/h produces the best economy. Find the "sweet spot" for yours!

 

[180degrees]

what brand diesel? my nav has always gotten 30-50km more on shell diesel instead of caltex vortex diesel.

also what tyres and do you have a bullbar?

265/75's for instance throw your economy out by making the trip computer report about 3-5% under what you actually did, also mud tyres chew more fuel, theres so many variables its hard to pin it on one thing.

distance measurements should really be taken with a satnav if at all possible because of this.

In the D40 YD25 peak torque is achieved around 2,000rpm which equates to around 95km/h on standard tyres (using a GPS to calculate speed, not the speedo). I am not sure about the D22, which has a different turbocharger and will have a different torque curve.

just to add to this, the D22 sits at about 2500rpm@100km/h actual so well into the meat of the power band albeit very narrow on the YD25...

 

[ST-R]

Mine is a 2010 and has done 30000 km. Only mod is EGR and usual Snorkle, Towbar, Tub liner etc. It never has used more than 10L/100 and gets near 9L/100 on occasion. I don't worry about driving at 2200rpm or any of that Schitte..Just drive it...

Your consumption is too high unless you cane it. Worth looking into.

Regards
Greg

 

[happy john]

I agree that's too high you should be getting 10 per hundred or less,as for the smoke on takeoff that is common on that model there was talk of new software to eliminate the smoke check with your dealer if you trust them.

 

[bods]

what brand diesel? my nav has always gotten 30-50km more on shell diesel instead of caltex vortex diesel.

also what tyres and do you have a bullbar?

265/75's for instance throw your economy out by making the trip computer report about 3-5% under what you actually did, also mud tyres chew more fuel, theres so many variables its hard to pin it on one thing.

distance measurements should really be taken with a satnav if at all possible because of this.


just to add to this, the D22 sits at about 2500rpm@100km/h actual so well into the meat of the power band albeit very narrow on the YD25...

not sure where you get that from, unless the yd25's have got different diff ratios to the zd30's. mine sits a tad over 2750rpm at 110 on the speedo (100 gps speed)...

mine is a 2010 and i have done around 43000km now, economy has always been pretty decent, although it does go down a bit sitting on 110 (actual speed, 120ish on the speeedo). average used to be around 8.5l/100km for me, but i don't do very long trips anymore so it's probably a bit more now. i do normally try and do a quick calculation when i fill up and it's always under 10l/100km, so as long as that's where it stays i don't mind...

 

[Pane]

Gday

Righto tony I use your exact method, so I've got that bit right. I always fill up at pump 3 in jerilderies bp servo so that parts right. I know the odometer is slightly out and the speedo is 10% out but I figure its constant so I just work off that. If I go off actual km travelled then the economy figure is worse again by about 3%. I know this cause I've measured 100ksys on the GPS and the dash says 103, speedo does however say 110 when doing 100.

So today I did another trip to Albury and back, theses are my figures
420 Kay's, 49.88 litres from the same pump at the bp. 11.87 litres per hundred. Now that was sitting on 105 nearly the whole way (towns excluded) empty tray on the way over 300kgs on the way home. Nearly exactly the same as the other day.

Like I said its always between 11.8 and 12.4 depending on how many times I've carted diesel to a job site. I did a week a while Back which was 140 Kay's a day half of which was fully loaded with fuel in my refuelling tank and some extra tools and this blew the numbers out too 12.8.

Thanks fr your input guys, my sig tells what the cars got too.

Cheers

 

[Old.Tony]

Next time, allow some extra time for the trip and don't exceed 95km/h and see what happens.

 

[Rhodie Al]

Hi guys,
Sitting at 110, speedo, I get between 9.5 and 10.5 over 550km's.
If I push to 120 or above, speedo, that figure gets totally stuffed getting upwards of 11.5 to 13 - all very dependant on how heavy the right foot is...
But as long as I'm in the 10 litre range I'm happy.

Al

 

[Pane]

G'day

I've done that tony on my weekly work trips, the best I can get sitting on 95 and not racing gears is 11.3 with the usual fuel tank and toolbox.

If I'm empty and sit on 80 only, same work trip and same pump at bp I can get down to 10.8.

I think it's too high, I've thought it was high since I bought it. I've tried all sorts of tyre pressures, driving like miss daisy. Revving out the gear changes slowly so not to create lag. I've even filled the fuel tank, carried extra drums of oil and all my tools for a week to see what that did, which actually resulted in 12.8. That surprised me actually I thought it would be higher.

Cheers

 

[bods]

I should say I pretty much only use caltex Woolworths for fuel. I've used shell for the odd tank or two but didn't find a lot of difference, although it was slightly worse economy. The caltex woolies station I go to normally has "premium" diesel only so that's what I use...

 

[Old.Tony]

Okay, so let's look at what can technically cause excessive fuel consumption.

Are your front hubs locked in or are they disengaged?

Dirty air flow sensors cause the car to underestimate the amount of air going in, making the fuel mix wrong (and you have to use more throttle to achieve the power you're after). It's like having a dirty air filter in reverse - the car is getting all the air, it's just measuring less air than it's actually getting. Happens a bit in the D40s.

There is supposed to be a software update for the ECU in the D40 KC which improves fuel economy from a 16-18LPHK down to a more D40-typical 10-12LPHK. I wonder if there's something similar for the D22 - the D40KC is a Thai build too. I don't expect your dealer will come straight out with "Yeah mate, we forgot about that *flash* there ya go, try it now = instant 9LPHK - but it'd be interesting if it came to be.

Another thing that people have had happen is the drum brakes - if you chock the front wheels, leave the car in neutral & handbrake off, jack the rear up and turn the wheels, is there a lot of resistance?

 

[Krankin]

We do have to remember that fuel bowsers by law can be out by up to 3% and it'll ALWAYS be in the servo's favour - so if you pump in what appears to be 100L of diesel, you may have only put in 97L.

Where can one find this law in writing???

I have an issue if I fill my 400ltr tank and in fact I'm only getting 388 ltr and paying for 400

 

[nakedape]

From what I remember from talks with gilbarco (bowser builders) they must be accurate and are tested regulary. So I doubt the 3% although 100% accuracy is nearly impossible.

 

[Old.Tony]

Where can one find this law in writing???

I have an issue if I fill my 400ltr tank and in fact I'm only getting 388 ltr and paying for 400

I made a mistake. It's 0.3% and you can find the regulation here.

Thanks for making me go look for it!

 

[Pane]

G'day

Hubs are always unlocked.

Thanks for your thoughts guys, I'll be on the phone this week to book it in for its 30,000 service so I'll see how I go.

Cheers

 

[nakedape]

I made a mistake. It's 0.3% and you can find the regulation here.

Thanks for making me go look for it!

Be honest now -- you were looking for it anyhow

 

[Navmania]

G'day

Hubs are always unlocked.

Thanks for your thoughts guys, I'll be on the phone this week to book it in for its 30,000 service so I'll see how I go.

Cheers

Unlock the hubs mate. The amount of drag will be putting your numbers up. Also fitting a bullbar and steel ARB rear bar and canopy to mine lost me 100k's a tank. Then by fitting a bigger exhaust I almost got it back. I measure my fuel from fuel light on then fill to first click at pump and I always get nearly exactly 64.4liters in. That's if I can get a fill within 10k's of the light coming on. It's always the same for me. Then I just note how many k's I have up when the light comes on. I know it's only rough, but its good enough to let me know if any mods I have done have had any big effect on consumption.

Cheers.

 

[bods]

^^he did say the hubs are unlocked...