D40 Fuel Economy

[drifter]

I get over the 700 km mark before the fuel light comes on, usually comes on between 720 -750km's thats around town/city and odd runs off with the bike on the back.

08' Stx 2.5 TD manual 6 speed

 

[Arty_74]

I'd be interested to hear from a few more ST-X V6 Auto 4x4 owners fuel usage as I really wanted a V6 when I was looking (bought a used car), the majority on the market were diesels so I thought I'd try one out.

I am a little disappointed with the figures I get around town in my Dual cab TD Auto compared to Nissans spec of about 9l/100km, I get anywhere from 12 to 14l around town but much better with lots of hway driving.

So I'm thinking I could have had all those extra kilowatts in the petrol for probably about the same fuel consumption, am I correct in saying this or does the petrol have a much higher fuel consumption rate?

Arty

 

[Old.Tony]

The petrol STX Dual Cab (V6 4.0L) is supposed to get 14.0LPHK, the diesel dual cab auto is supposed to get 10.5LPHK.

The tests are done with a stock, empty, near new vehicle driven by someone that really knows how to economise. However, as we've seen with users of this forum, those figures are really only a rough guide.

As a the weight gets added on, the fuel required to move that weight goes up. As a diesel ages, it seems to use a little less - ours started to improve at around 13,000km.

As for personal experience - my car is supposed to get around 12.2LPHK based on the extra 300-odd kg she's carrying. However, I've had 10.96LPHK. I know I'm not a perfect driver, so it's one of those vagaries. I'm generally getting 11.5s, which is still better than the 12.2 I am supposed to get - so I'm happy.

You could try the reset procedure on yours, to see if that helps. Check out this post in these forums for the D40 ECU Reset Procedure.

I have done this, there were no bad side-effects.

 

[ants_oz]

Actually, the tests are performed on a rolling road....a dyno....so they don't even take into account wind resistance! They are inferred figures that use an Aust standard cycle of urban transit events (that is, a set of events such as intersections, transits etc). It is all INFERRED...not actual driving on real roads.

 

[KraftyPg]

Ants is right and as it was pointed out to me years ago the tests they do are done in the manner they are so that every car is measured on an equal playing field. It would be pointless taking a Nav out in no wind and claiming 9's then the same driver taking a Lux out in high wind and getting 15's so all of those variables must be removed and the easiest way to remove the variables is simulate the same conditions for each vehicle.

The figures they put on stickers are there only to sell cars and give salesmen something talk about when convincing people to buy a car. Ask most salesmen why one car is better than another and they'll be able to quote economy figures but then get them to explain why two similar vehicles have different figures and listen to the ******** fly as they stumble for an answer.

There is no right or wrong figure, there is good bad and worse but suggesting we all should get 9's to begin with then increase that 9 by a percentage proportionate to the weight we add is not exactly right, sure more weight can increase the figures but every vehicle handles the weight differently and therefore not all increases will be the same. There is also the fact that adding 200kgs to the front will have a different effect to adding 200kgs to the back or 200kgs to the roof. You can also throw psychical size into the equation and make size and weight both come into effect, taller items that stand well above the roof line will effect wind resistance and therefore economy more than something of the same weight but fully enclosed in the tub.

I think the bottom line still comes down to treating every figure seen or told as a guide and not something you can definitely achieve or avoid.

 

[Old.Tony]

In that case, I've found the first lie that the salesman told me.

Then again, he might not know. Although, being in the industry, he should ... so I'll chalk this up as a fabrication. Not a serious one, mind you ... because if it's supposed to get 10.5 on a dyno, then being able to get 10.9 with the extra load out on the real road is a bonus.

 

[KraftyPg]

In that case, I've found the first lie that the salesman told me.

Delve a bit deeper into the memory banks, usually the lies (or extended truths) start just after they say "How can I help you?"

 

[coley350]

i think ya are all lucky getting 11s + 12s.

I got a 2009 stx diesel auto with 12k on the clock, i carry a large tool box on the back of the king cab that is near 1000kg, and get at best 17L per 100.

800km out of 145-150L

BFG at tyres, steel bull bar, winch, 150L long range tank, BOSS airbags, LPG (eco shot) More power diesel chip, Aluminium tray, duel batterys, air compressor.

Im getting the DPF pulled off next week as im sure its the cause of excessive fuel use.

Anyone else pulled the DPF off? what did you do with the sensors and 2 lines? what do the lines do? do they all have to go back in the new pipe?

 

[Old.Tony]

i think ya are all lucky getting 11s + 12s.

I got a 2009 stx diesel auto with 12k on the clock, i carry a large tool box on the back of the king cab that is near 1000kg, and get at best 17L per 100.

800km out of 145-150L

BFG at tyres, steel bull bar, winch, 150L long range tank, BOSS airbags, LPG (eco shot) More power diesel chip, Aluminium tray, duel batterys, air compressor.

Im getting the DPF pulled off next week as im sure its the cause of excessive fuel use.

Anyone else pulled the DPF off? what did you do with the sensors and 2 lines? what do the lines do? do they all have to go back in the new pipe?

Welcome to the forum, I notice this is your first post!

I would hesitate at removing the DPF. The regen cycle will use a little more fuel, but not that much. The sensors fore and aft of the DPF will trigger the ECU into "limp mode" if they differ too greatly in sensed pressure or if they're missing, so be careful with them.

For the moment, though, let's do a little math. Your King Cab is supposed to get 10.5LPHK according to Nissan's brochure. It has a tare mass of 1946Kg.

Adding another 1,000Kg increases the weight by 51.38% so the fuel consumption should rise by a similar factor (it's probably not linear, but it'll suffice as a guide for the moment). That means you should be getting 15.89LPHK.

Obviously there are other factors involved - traffic, driving style, tyres (both type and inflation level). Your ECU might be like mine, and need a reset - check this thread post for the procedure.

I also noticed that my fuel consumption started falling after about 13,000km on the clock - the diesels do seem to take a little while to "bed in" and become economical.

 

[Leprechaun]

i think ya are all lucky getting 11s + 12s.

I got a 2009 stx diesel auto with 12k on the clock, i carry a large tool box on the back of the king cab that is near 1000kg, and get at best 17L per 100.

800km out of 145-150L

BFG at tyres, steel bull bar, winch, 150L long range tank, BOSS airbags, LPG (eco shot) More power diesel chip, Aluminium tray, duel batterys, air compressor.

Im getting the DPF pulled off next week as im sure its the cause of excessive fuel use.

Anyone else pulled the DPF off? what did you do with the sensors and 2 lines? what do the lines do? do they all have to go back in the new pipe?

Seems to be a trend with King Cab owners.
I get 14's which I'm perfectly happy with my setup and driving style/conditions.

I would run your truck over a weigh bridge to see how much weight you've really put on.

 

[ants_oz]

Seems to be a trend with King Cab owners.
I get 14's which I'm perfectly happy with my setup and driving style/conditions.

I would run your truck over a weigh bridge to see how much weight you've really put on.

Ed-zachary....

Mine is a dual cab with manual trans, however with all the kit hanging off it my tare weight is actually somewhere around the 2300kg mark. Scary really.

 

[bigfluffys]

Let me know how you go, they still can't fix mine, haven't offered injectors yet.
My boat is 1.4tonne & if I take it from Sydney city to Mona Vale (don't know how far, bout an hour in traffic) i'll use nearly half a tank, must be well over 30l/100km!

Edit- After they saw the 265/75 mudddies they became less than happy to help out

Gday mate , yeah ive had injectors replaced under waranty as per the miss thay found at 2100 rpm ,just done another trip up coast now seems a little better at 16l/100 with camper on ,no boat this time,thats better by 5 or 6 l per 100 its still not great , as a mate of mine gets 12/100 with a big fricken 3t boat and a load of gear . ive done a 100k round town unloaded and got 14l/100 thats 2l/100 better than before but not great as 10/11 /100 is what most my mates get round town , im taking it back and getting them to reset the codes on computer as the service guy said that they have an intuitive learning computer and will set themselves to your driving pattern , and as alot of first few 5000km i was towing the boat with camper on ,as i have since found out they say not to tow for first 1000km , no one told me that a a drove out the door !(even though they knew the only reason i bought the thing was to put a big camper on it !! i wonder if its all screwed up by that ?? the service guy was really good , he said nissan wont touch anything related to "fuel consumption whinging" if under 20000km on clock thats why he never mentioned the excess fuel consumption when getting the authority to replace injectors he "found" a miss at 2100rpm and thats how i got them done , as the job would cost $4500 to be done normally , i think the trick is to get the service manager onside and get him to do the talking for you as without the guy i had nissan would have told me that the fuel consumption i was getting was "within the peratmeters" of the vehicle , yeah yeah ******** i say 25l/100 is **** and if thats te case i would have bought a **** OFF BIG V8 AND BURN BABY FUR SEALS STRAIGHT OUTA THE TAIL PIPES , any way the king cab is staying for a bit longer and it hope by getting the computer reset it may get better ......cheers

 

[blue boy]

bigfluffys.
is it only nissan that can reset your computer??

i'm looking at gettin a chip in the near future and thought maybe they could play around with the computers? even if you save 1 ltr every hundred km's, still adds up to a lot.

 

[Old.Tony]

bigfluffys.
is it only nissan that can reset your computer??

i'm looking at gettin a chip in the near future and thought maybe they could play around with the computers? even if you save 1 ltr every hundred km's, still adds up to a lot.

You can reset the ECU yourself by following the instructions found here.

I've done this, the vehicle was not damaged in any way, it behaved exactly as before - no noticeable coughing, spluttering or rapid left turns when driving past the local member of parliament's offices. If it's done anything, it has helped provide me a better-than-expected fuel economy - but it didn't do any harm. Nissan have seen the vehicle since and didn't draw anything to my attention, so they didn't notice.

 

[Leprechaun]

Straight after my last 2 services mine has run a little rough at idle, I'm guessing they performed the ECU reset, and it's just the ECU relearning it's idle mixture parameters. The idle cleans up after a few hours of driving.

 

[coley350]

I would hesitate at removing the DPF. The regen cycle will use a little more fuel, but not that much. The sensors fore and aft of the DPF will trigger the ECU into "limp mode" if they differ too greatly in sensed pressure or if they're missing, so be careful with them.

If i put all sensors etc back into the new 3 inch exhaust it should read as normal shouldn't it?? Just be no dif in presure pre and post dpf.?

Has anyone done this and what happened?

I see there are 3 inch exhaust systems on the likes of ebay from the turbo to the tip, with such systems do all sensors go back into the new pipe?

heres a link to one...

Nissan Navara D40 T/D Performance Exhaust - eBay Exhaust Systems, Exhausts, Car Parts, Accessories, Cars, Bikes, Boats. (end time 17-May-10 08:48:10 AEST)

they claim up to 20% better fuel and power.

what is the box right after the turbo on the d40s? is it a cat? i see this exhaust replaces that with a high flow one.

Obviously there are other factors involved - traffic, driving style, tyres (both type and inflation level). Your ECU might be like mine, and need a reset - check this thread post for the procedure..

Ill give the reset a go and be in touch!

 

[Old.Tony]

If i put all sensors etc back into the new 3 inch exhaust it should read as normal shouldn't it?? Just be no dif in presure pre and post dpf.?

Has anyone done this and what happened?

That's the general assumption. A free-flowing DPF should present the same pressures and temperatures before and after. A blocked one will not.

I see there are 3 inch exhaust systems on the likes of ebay from the turbo to the tip, with such systems do all sensors go back into the new pipe?

heres a link to one...

Nissan Navara D40 T/D Performance Exhaust - eBay Exhaust Systems, Exhausts, Car Parts, Accessories, Cars, Bikes, Boats. (end time 17-May-10 08:48:10 AEST)

they claim up to 20% better fuel and power.

While the 3" exhaust is going to provide some difference, alone I doubt it'll be 20%. You'd have to chip it as well. The 2.5" is quite a large system as it is, for a 2488cc engine.

what is the box right after the turbo on the d40s? is it a cat? i see this exhaust replaces that with a high flow one.

The manual calls it a "catalyst". My manual doesn't show a DPF at all, maybe I'm going blind.

Ill give the reset a go and be in touch!

Be good to see how you go after a couple of tanks of fuel.

 

[Pete22]

I see there are 3 inch exhaust systems on the likes of ebay from the turbo to the tip, with such systems do all sensors go back into the new pipe?

heres a link to one...

Nissan Navara D40 T/D Performance Exhaust - eBay Exhaust Systems, Exhausts, Car Parts, Accessories, Cars, Bikes, Boats. (end time 17-May-10 08:48:10 AEST)

they claim up to 20% better fuel and power.

Make sure that this is suitable for an auto 2008 and on....as I believe those previous to 2008 build did NOT come with a DPF. Could also prove problematic with any warranty claim you might have irt the ECU etc.

 

[coley350]

ok no worries. I do have a more power chip fitted, so im interested to see what 3" does for fuel + power.

Not worried about warranty, nissan wiped there hands over my ute! I got the eco shot lpg fitted and they warranty the whole vehicle for 5 years 100,000.

 

[coley350]

After reading about 200000000 posts i took the plunge and had a full 3 inch system fitted today from the turbo back, all pipe, no cat, dpf muffler.

Now, for those thinking of doing this it is THE BEST upgrade possible for power!

The thing hammers, the turbo spools up heaps faster, you can hear the turbo whistle, Very small amount of engine noise, just nice.

We will see in the comming weeks to how the fuel acconomy goes.

the flex pipe in the stock system is 2 inch inside restricting the thing, the cat chokes it up like you wouldn't believe.
Ive got LPG fitted, and runs a small amount before the turbo making it clean burning, no black smoke at all.

Also got more power diesel chip fitted.

its a totally different car.

if you are thinking of doing it, dont hesitate.

Ill be in touch with fuel figures as soon as i have some.