D40 Fuel Economy

[Old.Tony]

Nah its a Thai made I think (VIN:MNT). And yeah I'll try all that after I get it serviced and see what the mechanic thinks as well. And as for the RPM I am roughly around 2000 to 3000 on take off, but ill start to aim between 2500 and 3000.

Haha sorry for the silly question but I thought the 'D' stood for drive ?

It does, but there's a trick: if you turn overdrive off, you'll be in 4th gear. In 5th, the torque converter will lock (it won't lock in any other gear in our cars, yours is the same as mine). This lock removes the rev loss in the transmission that you normally get in an automatic.

At 2000rpm you're losing too much power to slippage in the torque converter. It's a nice gentle takeoff, but the loss adds up over time. The stall speed of the TC is supposed to be somewhere in the 2700-3100rpm region (Nissan's specs). The closer your engine is to this RPM the more the TC grabs the input force.

Wholesale Automatics sell a low-stall TC (stall speed around 2400rpm) which will not only save fuel, but will provide a more positive feel and better engine braking - I don't believe they're cheap though. It'd be the kind of thing I'd consider getting if my TC gave up once my car was out of warranty.

 

[TroyMac]

It does, but there's a trick: if you turn overdrive off, you'll be in 4th gear. In 5th, the torque converter will lock (it won't lock in any other gear in our cars, yours is the same as mine). This lock removes the rev loss in the transmission that you normally get in an automatic.

At 2000rpm you're losing too much power to slippage in the torque converter. It's a nice gentle takeoff, but the loss adds up over time. The stall speed of the TC is supposed to be somewhere in the 2700-3100rpm region (Nissan's specs). The closer your engine is to this RPM the more the TC grabs the input force.

Wholesale Automatics sell a low-stall TC (stall speed around 2400rpm) which will not only save fuel, but will provide a more positive feel and better engine braking - I don't believe they're cheap though. It'd be the kind of thing I'd consider getting if my TC gave up once my car was out of warranty.

Hmm, I'll probably just leave the TC and just put my foot down a bit more haha

Thanks Tony

 

[justbruce]

My fuel economy before EGR block.
My driving is mainly country roads and a little bit of town driving. Lots of hills, and about a tonne in the trailer.
I have kept my fuel receipts and recorded the km for every fill between 2 services.
My last service was 200,000km, so it is not a new engine.
Over 10,000km I averaged 10.76L/100k
I try to fill the tank to the same level every time, (first click off, at the same pump in town).
I expected the economy to be worse immediately before the oil change and best immediately after. Not the case. The 1st tank full after both services was 11.53 and 11.34. It is as if the mechanic has taken about 2 litres each time, NO I AM NOT accusing my local mechanic of stealing dieso.
A few other things have happened during this time.
My tyres went from 255/70r16 to 265/70r16, there was no change I could notice.
Secondly, our local servo has stopped serving winter diesel. Again I didn’t notice any difference.
During the 2nd week of September, I got 9.528, and 9.53 L/100k. I was going to discount these because they are so far below my average range. Then I remembered that was night driving in sub zero temperatures at half speed through snow and fog.
I have now blocked the EGR and installed an oil catch can. Can anybody guess how much difference this will make…

 

[Old.Tony]

Your local mechanic may not be stealing diesel, but he's running the engine at some point and our diesels use around 2 litres per hour to idle.

Your catch can may not provide any efficiency gains, but blocking the EGR should - more often than not the EGR gains aren't noticeable, but if your driving style is consistent they are measurable. A few people have reported a noticeable change in their power/spool times - I think it depends on the person themselves.

 

[justbruce]

I'm not concerned about my diesel being taken. Our mechanic is extremely reputable and reliable. I don't begrudge him taking our sump oil and using it in his workshop heater either.

My biggest surprise was the fuel economy in cold weather. Yes, I was driving a lot slower, but it was 4wd in 3rd - 4th gear.
I was not expecting freezing cold air to give an extra 80 km per tank.

 

[Old.Tony]

It's not a huge surprise. Intercooler efficiency will rise considerably and with the denser air, it'd be like adding a few psi to your boost levels.

 

[queenie]

First post here......Owner of a 2012 D40 auto... currently getting around 14l/100 km which I'm not too happy about because I think I should get better. mon-Fri is around town with some weekends out and about .... ute has 52313 on the clock... bull bar and tow bar installed. ..

 

[Old.Tony]

Welcome to the forum.

First thing to check is the accuracy of the measurements and that basically comes down to tyre size. If you're using larger tyres your odometer won't read as many km and your apparent fuel consumption will rise (it does because of the larger tyres, but not as much as you'd think). On standard tyres your ODO is quite accurate.

Next, the in-dash display of LPHK isn't always accurate so relying on bowser litres and tripmeter km is the most accurate alternative.

There's a way to deal with the tyre size issue. Find out the standard tyre size for your car, then find out what percentage your current tyres vary from that. Multiply the indicated km by that amount, then do your economy calcs.

Example: 2010 D40, stock tyres = 255/70R16. Car currently has 265/75R16 tyres. Original rolling circumference = 2398mm, current tyres = 2610mm = 5% larger. Indicated km for 72L of fuel = 510, providing an apparent economy of 72/5.1=14.1LPHK. Calculated km is then 510*1.05 = 535km so actual economy is 72/5.3=13.5LPHK.

It's not a lot of variation but I did choose a tyre that was fairly close in size. If you've got 285/70 tyres your variation is 16% so calculated km would be 510*1.16=591km and economy becomes 72/5.9=12.2LPHK. And for a large tyre, that'd be pretty good, since the larger the tyre, the harder it is for the engine to turn it over (lever from axle midpoint to road surface).

 

[maxmalone]

Thail built D40 with 265/75 I get abotu 13.75lt/per 100kms, that's normally with all the camping gear and setup.

It will raise a little more when the roof racks get fitted.

 

[NAV012]

2012 D40 Manuel getting around 8.9 highway 9.4 combined and 10L around town pretty happy running around on 265/65R17 Maxxis Bravo 980 At

 

[chris92]

Hey guys, ive got a 2012 dual cab ST. When i first got it brand new i was getting around 700-750km to a tank, both highway and in town driving. Now, nearly 3 yrs later, i can only manage to get around 550km for the same driving.. Ive always had a bullbar since new. Ive recently put on a 3" exhaust and egr blank, and it hasnt made it any better. Like they say and exhaust should.

 

[subz123]

Hey guys, ive got a 2012 dual cab ST. When i first got it brand new i was getting around 700-750km to a tank, both highway and in town driving. Now, nearly 3 yrs later, i can only manage to get around 550km for the same driving.. Ive always had a bullbar since new. Ive recently put on a 3" exhaust and egr blank, and it hasnt made it any better. Like they say and exhaust should.

Maybe try some liqui molly injector cleaner that helped with my fuel economy

 

[subz123]

I have an 2010 stx 140kw Im running 33's with steal bar ,canopy ,roof racks ,5inch lift. My avarage fuel consumption is 10.0l
Im doing to bout 620 to the tank.

 

[chris92]

Ive tried the Nulon diesel injector cleaner but that hasnt made much difference. I will have to give this liqui molly stuff a go.

 

[subz123]

Trust me its the best thing ever invented i used it 2 times in a row first time didnt see much difference. Secound time i filled up a half tank stronger mix thats when i noticed big difference more quieter smother and better fuel economy. Good luck

 

[chris92]

Cheers subz123 ��

 

[chris92]

Subz123, did you use the liqui moly injector cleaner or the fuel system cleaner/conditioner?

 

[subz123]

Looks like this

 

[subz123]

Repco have f0r $27 and super cheap have it for $24.5

 

[chris92]

Cheers mate