Towing with Hilux

Submitted: Thursday, Jul 20, 2017 at 12:08
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I'm towing a 2 tonne caravan with a 2011 Dual cabSR5 Hilux diesel and only getting 340km per tank and power is low. My question is my oppositions do i need to update my car or will i get better economy and power if i add a Roo System.
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Reply By: Member - mechpete - Thursday, Jul 20, 2017 at 12:24

Thursday, Jul 20, 2017 at 12:24
the first thing I,d do is weigh the whole combination
you may be shocked , is the Hi Lux in good running order
mechpete
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Follow Up By: Member - warren G (VIC) - Thursday, Jul 20, 2017 at 20:19

Thursday, Jul 20, 2017 at 20:19
engine size should be a match to weight carried adding a chip regardless of all the hype will shorten engine life a factory spec engine good for say 300000lk in normal use put same engine in a drag com and get maybe 10 races with a chip your hilux should fall some where in between, a bit exaggerated go for a bigger veihcle but good luck with it anyway
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Follow Up By: Paul E6 - Saturday, Jul 22, 2017 at 22:54

Saturday, Jul 22, 2017 at 22:54
Punctuation for Pete's sake.
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Follow Up By: Member - David M (SA) - Thursday, Jul 27, 2017 at 20:27

Thursday, Jul 27, 2017 at 20:27
Stop complaining. There's a comma after between.
Dave. :)
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Reply By: RMD - Thursday, Jul 20, 2017 at 12:34

Thursday, Jul 20, 2017 at 12:34
Is it auto or manual?you didn't say.
With either, if you try and drive in too high a gear ratio it will load the engine and suck more fuel than it should for no benefit.
The airflow meter and turbo boost sensing devices may be dirty and not indicating true info to the ECU so fuel use will rise under load.
Are they clean? Is your airfilter clean? It may not be if dealer serviced.
If high km truck, are the engine valve clearances correct? Do you have oversize tyres which cause greater fuel use, especially when towing.
Are your vanbrakes adjusted properly? Dragging brakes and incorrect tyre inflation will lower economy too.
All these should be checked or corrected long before thinking of a new vehicle (nice as it may be) or a chip from 4wd shop.
The chip won't ever make brakes, driving style or poor maintenance better and will likely cause problems if all systems are not correct in the first place.
Cheers
AnswerID: 612639

Follow Up By: Member - dean f3 - Thursday, Jul 20, 2017 at 14:31

Thursday, Jul 20, 2017 at 14:31
Hi all and many thanks,Hilux max towing is 2250kg it's an auto 3lt. Weights are van 2.060 and car 2.480 total 4.540, the car is in excellent condition and has 188,000 on the clock there is also a snorkel fitted. I realized the economy will be down due to the caravan being full height, the tires are at 44 psi and breaks are not dragging. Before chip and exhaust system is fitted the mechanic will be going over fuel systems from filter to injectors, may have carbon build up in manifold maybe the problem. Went out to Birdsville for the big bash and was very disappointed with power and economy, we are intending on going down the east coast to Tasmania and would like to know if Hilux would be able to cope with the trip.Would the Roo system up grade be useful or do we need up grade in car that can tow 3tn.
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Reply By: Batt's - Thursday, Jul 20, 2017 at 13:12

Thursday, Jul 20, 2017 at 13:12
I would say that's pretty good econ considering your probably around or beyond 4.5t loaded. You say add Roo systems is that chip or exhaust or both ? Is it a full height van which will add a lot of extra wind drag compared to a pop top which are a lot more economical to tow. Also mentioned above tyre pressures that can make a big difference if their not pumped up correctly so all the tyres are wearing evenly.

You can add the chip, exhaust but I would fit a snorkel as well to help compliment the new system. If you supply cool fresh air to the engine you will get the full benefit of the exhaust extracting the spent gasses they go hand in hand. If it's turboed an intercooler up grade will also help to increase torque more than power. So all up with a reasonable power increase form setting it up correctly you will need less throttle now because the engines power and torque figures will have increased more torque is the main thing that will help when towing so that should equate to less fuel used now because you need less throttle to drive the same way but still remember your towing a heavy brick with a heavy brick.

After all that is done hopefully your gear box, drive line can handle the power gains when towing a lot of weight without damaging it.
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Follow Up By: Les - PK Ranger - Thursday, Jul 20, 2017 at 13:48

Thursday, Jul 20, 2017 at 13:48
3 very good replies so far . . . added to Batts above, if yours is an auto, I would also upgrade to a higher capacity transmission oil cooler, as these are under a heap more stress touring with a larger / heavier van, which it sounds like it could be.
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Follow Up By: Member - dean f3 - Thursday, Jul 20, 2017 at 13:57

Thursday, Jul 20, 2017 at 13:57
Hi all and many thanks,Hilux max towing is 2250kg it's an auto 3lt. Weights are van 2.060 and car 2.480 total 4.540, the car is in excellent condition and has 188,000 on the clock there is also a snorkel fitted. I realized the economy will be down due to the caravan being full height, the tires are at 44 psi and breaks are not dragging. Before chip and exhaust system is fitted the mechanic will be going over fuel systems from filter to injectors, may have carbon build up in manifold maybe the problem. Went out to Birdsville for the big bash and was very disappointed with power and economy, we are intending on going down the east coast to Tasmania and would like to know if Hilux would be able to cope with the trip.Would the Roo system up grade be useful or do we need up grade in car that can tow 3tn.
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Follow Up By: Les - PK Ranger - Thursday, Jul 20, 2017 at 14:09

Thursday, Jul 20, 2017 at 14:09
Yeah, towing what is effectively a brick is terrible, even a little gear on a roof rack is noticeable to most drivers.

Good first port of call having all those things checked by the mechanic Dean.
If he knows his stuff he might well get to the bottom of it and rectify the issue.

If there is carbon (EGR soot and PCV oil mist mix) in the manifold, it would be a really good idea to eliminate at least the oil mist with a Provent 200 catch can.

Even better, do the catch can AND though not legal, an EGR 'fix' is worth thinking about.
EGR is a filthy system, and when your lovely diesel engine MAP sensor etc gets coated, a vehicle can run poorer anyway and pollute as much or more than with NOx reduced by an EGR system.

Towing though, your vehicle would be under load a lot more, and the EGR would normally be turned off in that case, the EGR is only open when cruising with little load, downhill etc.

My EGR fix has a neat cabin mapper (fuel adjustment) and also this little LED.
It glow amber when the EGR is normally open (bad) and green when it is normally closed, it gives me a good idea just how much the EGR is on or off under what circumstances.
My EGR is blocked with a 2mm blank plate (just to be sure :)), on top of the electronic 'turned off' signal 100% of the time . . .
Google ozbushelectronics . . . he makes them for the Prado and Hilux, as well as Rangers / BT50s.

Very good economical mod, the cabin mapper model is the go, can adjust fuel up / down a little, thoguh I really don't even notice the difference, you might when towing.
I only got it for the EGR fix.
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Follow Up By: Paul E6 - Saturday, Jul 22, 2017 at 22:58

Saturday, Jul 22, 2017 at 22:58
When I had an egr blank, I would get codes under high load driving.
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Follow Up By: Les - PK Ranger - Saturday, Jul 22, 2017 at 23:56

Saturday, Jul 22, 2017 at 23:56
Many vehicles will get a CEL light come up with a EGR blank plate fitted Paul.
Some makes don't apparently.

In vehciles that do get codes come up, then and 'Insufficient EGR flow' is detected and an error code P0401 will usually come up in a short time.
Some vehicles can be sorted by drilling a small hole (usually around 10mm) in the blanking plate, so most gases are stopped, but not all.

Or better, the Ozbush Electronics module ensures no codes.
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Reply By: swampy - Thursday, Jul 20, 2017 at 16:33

Thursday, Jul 20, 2017 at 16:33
hi
Direct injection appears to wear out injectors a lot mainly due to its very very high pressures .Only a few years ago some injector companies started using industrial diamonds near the spray tip to reduce wear . Tojam 3.0ltr has had different /upgraded injectors about every 2 years to combat this .

I replaced the injectors in my early Ranger at 70,000kms /300 kms to a tank .

At least check and inspect manifold for contamination .

Have a compression test and a leak down test is a must .

Yes Toyo are gutless an exhaust and chip sounds great

Oz bush electronic take a look
AnswerID: 612642

Reply By: qldcamper - Thursday, Jul 20, 2017 at 17:48

Thursday, Jul 20, 2017 at 17:48
be wary of trying to increase the power beyond standard, these engines have a weak point being the pistons, many have suffered from cracked pistons, more power or torque equals more combustion heat and hence more stress on the piston crowns.

Get the car checked out as you intend, carbon build up in the manifold is very common in the 1kd engine, as is injector problems and the airflow sensor is prone to become fowled and cleaning is included in the dealer service schedule in the latter models and also as mentioned earlier there is a filter between the manifold and the manifold air pressure sensor that benifits from a good clean with contact cleaner from time to time.

I am also pretty sure it is mentioned in the latter handbooks that you shouldnt tow substantial loads in drive, to use 3rd, many transmissions have been damaged due to this, not from over heating but the bearings and gears in overdrive cant handle it.

If your not happy with the way it tows once you know it is running as sweet as possible standard i would opt for a larger class of vehicle rather then run the risk of modifying it to screw more power out of an already hard pushed engine.

Have a look at newhilux.net, huge amount of info there from owners and technicians sharing experiences.
AnswerID: 612643

Reply By: Member - RobnJane(VIC) - Thursday, Jul 20, 2017 at 18:14

Thursday, Jul 20, 2017 at 18:14
Hi Dean, To add to the info already supplied, I suggest a little more research or consideration be undertaken before spending what is going to be a reasonable amount of money that may or may not give you the result you seek.

Does the car perform and provide acceptable fuel economy when not towing?
How long have you been towing this set up?
What speed are you trying to maintain, on sealed and unsealed roads?
Does the car have a bullbar fitted?
And a roof rack?
Is the van an off-road, or dirt road set up, therefore likely to be higher and with more aggressive tread pattern light truck tyres?
Given the distance covered it is likely the highway biased oe tyres have been replaced by more aggressive pattern all terrains of light truck construction.
We don't know what actual economy is being achieved as we don't know how many litres constitute a tank full, ie do you use nearly all the fuel or fill again at about a quarter of a tank, etc.
Did you check fuel economy on both the sealed road section and unsealed section to see what difference there was.
To my knowledge both rolling resistance and wind resistance increase exponentially from around 90-95kmh so if trying to travel at 100kmh you can expect to use plenty of fuel for very little gain.
So given I am making a 'wag' I would start with things I control, so check consumption accurately,towing and not, don't tow above 95kmh, do not allow the 'overdrive' function in the auto to function once at higher speeds ie 80kmh and above, as was noted in an earlier reply increase your engine speed, and lower road speed.
Hopefully you can improve your results to an extent you are happy with without spending a lot of money, and if you do decide to modify the vehicle then you really should do the payback calculation to see just what that might demonstrate.
RobnJane

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Reply By: Member - dean f3 - Thursday, Jul 20, 2017 at 18:26

Thursday, Jul 20, 2017 at 18:26
Thanks to all, with all your knowledge and helpful input it's been much appreciated cheers
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Follow Up By: Dean K3 - Friday, Jul 21, 2017 at 22:07

Friday, Jul 21, 2017 at 22:07
Tad concerned about the GCM being (just over 4500) from what i can figure out with simple maths C class licence only allows maximum 4500 kg so your out of class weight wise and insurance null n void and if a smart pants lawyer or accident investigator was to check weights involved might be in bigger hole than a grave

I have a prado d4d auto so in principle the same configuration.

Have you ever has ERG system checked for blockage this may make a world of difference - have system cleaned and fit a provent or similar (oil catch can) to prevent erg being fouled

injectors are a must if you have access to a OBD2 reader try get pressure reading taken when at normal tempreture LOD is reading I believe is needed (read that on another forum) mien still new from 2008 245,000 km so far no issues touch wood

Prado auto boxes are very sensitive to gear hunts esp when towing - suggest a minimum of a torque convertor lock up kit still allows gears to change up n down just need to unlock it like disengaging a clutch when coming to a stop otherwise engine stalls
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Follow Up By: Frank P (NSW) - Saturday, Jul 22, 2017 at 13:05

Saturday, Jul 22, 2017 at 13:05
Dean,

"Tad concerned about the GCM being (just over 4500) from what i can figure out with simple maths C class licence only allows maximum 4500 kg so your out of class weight wise "

If you are quoting the following from this link

Under a C (Car) licence you can drive
"A motor vehicle (with or without a trailer), other than a motorcycle, that:
has a maximum weight of 4.5 tonne (t) gross vehicle mass (GVM)"

then I would have to say that is the most confusing and ambiguous bit of govt departmental gobbledygook I have seen for a while.

If you remove the motorcycle exception to simplify the sentence so it reads

Under a C (Car) licence you can drive
A motor vehicle (with or without a trailer) that has a maximum weight of 4.5 tonne (t) gross vehicle mass (GVM)

Does that mean you can drive a motor vehicle with a GVM of max 4.5 tonne and then attach a trailer?

Or does it mean that the motor vehicle and attached trailer must not weigh more than 4.5tonne? In which case the term "GVM" is inappropriate because by definition in ADRs that applies only to motorised vehicles. The correct term for the max combined weight of a combination is GCM for Gross Combined Mass - again defined in ADRs.

I think it means the former, and that you have interpreted it to mean the latter.

If it did not mean the former, then just about every caravanner would be "out of class" which I'm sure is not the case.

Cheers
FrankP

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Follow Up By: Batt's - Thursday, Jul 27, 2017 at 19:38

Thursday, Jul 27, 2017 at 19:38
Yes I think that would be a bit of a concern there would potentially be thousands of drivers out there with the incorrect licence for towing with a GVM max of 4.5t. That is the max weight you can drive with on a C class licence and it doesn't make any difference if your towing or not as towing your total max weight cannot go beyond 4.5t so a light truck licence may be in order for lots because if you have an accident and your insurance finds out I expect you may not be covered. The other concern would be if there is another vehicle involved the damage to them or their vehicle may not be covered by your insurance if your at fault. I may be wrong but it's worth checking up on.
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Follow Up By: Dean K3 - Friday, Jul 28, 2017 at 19:00

Friday, Jul 28, 2017 at 19:00
I had a discussion about this matter with a DOT heavy vehicle inspector (west aust) about the GVM GCM issue and 4wd towing caravans etc on another forum.

They agree its a very vague area per say there isn't a value mentioned for GCM only GVM and these two terms are totally different values.

They are of same opinion of mine needs to be less then 4500 kg all up and they will charge fine a operator of vehicle if they can obviously see its being run overweight, they will put it onto scales and check against manufacturers specifications. and advise about weight distribution etc.

They also fully support the notion (as do I) that anybody towing needs to have a special towing endorsement on their licence.

Remember the uproar of needing a recreational licence for operating a tinny/runabout for maybe once or twice a year - all about safety and competency,

Same thing applies to towing I have watched many a folk at local waste transfer station trying to reverse a trailer with a smaller hyundai I20/30 plus larger vehicles just add ibenny hill theme song and you have the idea.

I confess a 6x4 behind a prado is invisible why I go for 7x5 when towing a hire trailer !
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Follow Up By: The Bantam - Saturday, Jul 29, 2017 at 17:14

Saturday, Jul 29, 2017 at 17:14
Lets get this straight

A pesenger car licence alows you to drive a vehicle up to 4.5 tonnes WITH a trailer up to 4.5 tonnes ... nationally.

Its scary to many of us that you CAN drive a 9 tonne combination on a passenger car licence yet require a higher rated licence to drive a much safer and easier to drive vehicle over 4.5 tonnes ..... like an unmolested Coaster buss ..... from memory a coaster is 6 tonnes GVM from the factory with a 2 tonne tow rating ..... many have their coasters recomplianced as a 4.5 tonne GVM vehicle.

I don't know about the other states but the published guides in QLD (not legeslation) make this abundantly clear.

there are other similar allowances for the various heavier licences ... light, medium and heavy rigid licences allow you to tow a trailer up to 9 tonnes GVM.

now here is the fun bit ... the GVM is the mass at the wheels ...... SO you can have fifth wheel articulated trailer with an agirigate trailer mass of 5.5 tonnes and tow it on a passenger car licence because its GVM can be 4.5 tonnes with a tonne borne by the hitch on the back of a tow vehicle less than 4.5 tonnes

Likewise On a medium rigid licence one can drive a medium rigid drawn 12 tonne single axle semi-traler, because 9 tonnes is borne by the axle and 3 tonnes borne by the prime mover ...... Coca Cola are running similar rigs as we speak.

If you are going to play this towing game ... YOU MUST know your licence regs and all the terms related to load carrying and towing.

GVM
ATM
GCM

and a number of other terms a MUST KNOW things.

cheers
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Reply By: peteC - Thursday, Jul 20, 2017 at 19:25

Thursday, Jul 20, 2017 at 19:25
For you to think about. I have same but manual, towing jayco outback camper around 1300 kg loaded ( guesstamat ). I have mods now so will use figures before wheel/tyre upgrade.

Empty all types of roads 9.5l/100
Towing 11.5/100 all types of roads
Towing long distance constant Ave 110km/hr high as 12.5l/100.

With mods max I have ever got 14l/100.

Given your up around 19-20l/100 I think there is something wrong even auto and van height unless your doing some serious high speed.

Not a fan of the chips, too much stress for a little if any fuel economy and maybe extra power up the hills. If you towing the van relax and just enjoy your holiday.

As mentioned carbon build, up injectors, good going over my be all required by the right mechanic and auto trans mechanic
AnswerID: 612647

Reply By: AlbyNSW - Friday, Jul 21, 2017 at 05:52

Friday, Jul 21, 2017 at 05:52
I would clean your MAF sensor and check your injector values to make sure all is good before looking at other performance options
AnswerID: 612649

Reply By: Ron N - Friday, Jul 21, 2017 at 11:26

Friday, Jul 21, 2017 at 11:26
At 188,000kms, if the injectors haven't been replaced, they should be.
The injectors in todays common rail fuel injection systems are only good for 100,000kms before they need replacing.

It's not that the injectors are poorer quality, it's because they are running on cutting edge technology.
Injectors in older mechanical injections systems operated with 0.0025mm clearances - today they have clearances as little as 0.001mm, and even the slightest amount of wear in injection components in a CR system leads to a fall-off in performance.

A critical component in the CR injection systems is the fuel control valve which supplies the fuel at astronomical pressures to the injectors.

The fuel control valve contains a tiny (1mm diameter) ball-type check valve, which primarily controls the CR system fuel injection pressure.

If the check valve ball and seat wear (as they do after substantial kms, and after having to cope with small amounts of water and microscopic dirt), then the high pressure required to be sustained by the check valve is reduced, leading to poorer fuel atomisation and lower fuel economy.

In addition, a lack of regular valve clearance adjustments are a factor that can badly affect fuel economy and power.

I would be indulging in an engine tune up, covering the above factors (injectors, injection system and valve clearances) before I did anything else.

Cheers, Ron.
AnswerID: 612656

Follow Up By: Michael H9 - Friday, Jul 21, 2017 at 18:13

Friday, Jul 21, 2017 at 18:13
The injectors in my Landy are almost on 300k and never been touched except to be tested a few months ago at my request. They said nothing wrong. It's a modern crd.
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Follow Up By: Paul E6 - Saturday, Jul 22, 2017 at 23:03

Saturday, Jul 22, 2017 at 23:03
Agree, 100k replacement is a generalization.
May be true for non-CRD engines.
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Reply By: The Bantam - Saturday, Jul 22, 2017 at 12:30

Saturday, Jul 22, 2017 at 12:30
As has been mentioned you should be aware that you are towing very close to the capacity of the vehicle.

Second and very importantly do you know how to drive it.

If you have not driven diesels particularly heavily loaded diesels you may be "doing it wrong".

Just because you have an automatic gearbox ( and modern auto's are impressive), you should be expecting to manually control shifts.

You need to be keeping your RPM in the fairly narrow sweet spot, ALL turbo diesels have, and that is where around where the torque and power curves peak.
In most small diesels this will be around the 3000 to 3500 RPM.

If you need to keep pulling do not be afraid to run right up to the rev limiter ..... it is pretty much impossible to over rev a diesel motor ...... though there is no power advantage past the peaks in the power and torque curves.

For maximum efficiency and maximum power you need to be sitting right in the middle of the sweet spot.

Unlike petrol motors keeping the RPM down does not necessarily help fuel economy.

your modern Automatic will have an overdrive gear ..... like the 5th gear in most manuals ...... do not expect to tow in this gear except in long down hill runs.

And yes you need to be in the right gear and at the right revs well in advance ...... don't for a minute expect to be in the wrong gear and too low in the rpm and expect it to pull properely and get good fuel economy.

OH yes and pushing a turbo diesel hard low in its rev range will result in EGTs and cylinder temperatures to rise dramaticaly ...... this is what burns up turbos, cracks and burns holes in pistons and causes a lot of other internal heat related dammage.

So do not expect to just stick the transmission in "D" for drag and push the small pedal and expect anything good to happen.

Oh and yes most of these modern turbo diesels have a problem founing the inlet system due to a combination of exuaust gas recirculation and positive crank case ventilation ...... PARticularly if they are babied around town and or run hard in their low RPM ...... the systems don't flow properly and thus clean themselves.

An oil catch can in the PCV system probably should be considered.

cheers
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Follow Up By: The Bantam - Saturday, Jul 22, 2017 at 22:09

Saturday, Jul 22, 2017 at 22:09
The other thing to remember is hilux dual cabs have pretty small fuel tanks .... the single cab diesels have about 50% more capacity.
AND because diesel engines use recirculating fuel to cool in injection system the whole tank capacity is not available for burning

so ya probably got a 60 litre tank of whick 50 is litres is available and you probably refill around 45 is litres .... ya doing reasonably well to get 350 odd Km

cheers
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Follow Up By: Dean K3 - Friday, Jul 28, 2017 at 18:44

Friday, Jul 28, 2017 at 18:44
In most small diesels this will be around the 3000 to 3500 RPM.

Geezus 3000 rpm and slightly above prado is running out of puff and like the original poster we both have similar engines redline line is 4000 rpm maximum

max torque on 1kd fitted to my 08 prado is around 2000 rpm when I do a manual shift point change at 2500 (on the road) then it settle back down to 2000 rpm only if i have to give it herbs (get that gap between traffic from standing start across highway) would I use 3000 rpm or more but only in D not a lower gear
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Follow Up By: Ron N - Friday, Jul 28, 2017 at 19:54

Friday, Jul 28, 2017 at 19:54
Nothing beats low RPM's for diesel engine economy. One you start going over 2500-2750 RPM's, a lot of unburnt diesel starts going out the exhaust, because it's a slow-burning fuel.
To give you some idea, the latest Cummins truck engines are sitting on 1100RPM at 105kph, to get maximum fuel economy.

I've got a 2013 Hilux single cab with the 1KD-FTV diesel - and this engine produces its maximum torque at 1400 RPM (343NM). Mine is a manual. I don't like the engine sitting on more than 2700 RPM for long periods - but 2700 RPM is 115kmh in 5th and that's plenty fast enough for me.
I only rarely exceed 3000 RPM when doing a quick overtaking manouevre - and I then settle back to 2500-2600 RPM.

This engine is a good little performer, I get 8.5L/100km lightly loaded and rarely get worse than 10L/100km when loaded and not towing.
Towing a little over 2 tonnes usually sees the economy drop to around 14-15L/100km. The single cab has an 80 litre fuel tank, the dual cabs tank is 76 litres.

If you follow anyone towing maximum GCM with a 3.0L diesel, you can see the fuel economy they are getting, by the amount of black smoke pouring from the exhaust. It can be pretty enlightening, watching this.

Lots of black exhaust smoke is simply lots of unburnt diesel going out the tailpipe.
A diesel running properly and economically should only ever show a dark haze from the exhaust, with no visible smoke.
One needs to remember that visible exhaust smoke for 10 continuous seconds, is all that is needed for the Monarchs to give you a yellow sticker.

Cheers, Ron.
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Follow Up By: The Bantam - Saturday, Jul 29, 2017 at 14:11

Saturday, Jul 29, 2017 at 14:11
Different engines in different vehicles have a different sweet spot ........ if ya want to push the low RPM thing some of the big old diesels are on the rev limiter at 2000 rpm.

What a cummins engine is doing is irrelivent to what a 3 liter hilux is doing.

Whatever the vehicle sits on at 100Kmh in fifth gear is usually an indicator of the sweet area .....

Black smoke coming out of diesels is often an indicator of being over fueled at too lower RPM



The 1KD-FTV is a 3.0L (2982cc) straight-4 common rail D-4D diesel engine with a variable nozzle turbocharger (VNT) and Intercooler. It has 16 valves and a DOHC (double overhead camshaft) design. Bore is 96 mm and stroke is 103 mm. It generates 172.72 hp (127 kW) at 3400 rpm, and 260 lbf·ft (352 N·m) of torque at 1800-3400 rpm depending on target market and emission specifications. In some markets, outputs are 127 kW (170 hp)/410 N·m (302 lb·ft) and 140 kW (188 hp)/ 420 N·m (310 lb·ft).[citation needed] Redline of this engine is at 4200 RPM. Compression ratio is 17.9:1.

If you look at the power and torque curves in this following document you will see that at 2500rpm you are getting about 2/3 of the power available at 3500 .... you will also note that the torque and power curves fall over after 3500.

http://www.powerchipgroup.com/datasheets/1/TOY0098.pdf

Yeh you might get good fuel economy out of lightly loaded diesels at low RPM ...... but they simply will not be making enough power to do the job ....... efficiency of diesels is better at higher RPM in the sweet spot, because they are a compression operated engine and the quicker and harder the air fuel load is compressed the more efficiently it burns.

The slow burning nature of the fuel is why the torque and power curves fall over after about 3500 rpm in small engines. .... in that particular engine ( the 1kd-ftv) the torque curve never peaks ..... but it does fall over.

Compression efficiency increases with RPM till it is limited by the fuel burning speed .... thus the same power curve ( with different figures) pretty much in nearly every modern smallish diesel.

Running heavily loaded diesels at low RPM is a mistake many people adhere to .... for many people it is an emotional choice ..... they just can not concieve that running a diesel at high RPM is a good thing ......running a diesel heavily loaded at low RPM, makes smoke, burns more fuel results in higher EGTs and simply does not make the necessary power.

As for sitting on 115Kmh at 2700RPM ..... that is the vehicle sitting on the back of the power curve right where it should be ..... it probably sits at about 100Kmh in fifth it will be sitting around 2400 ....... but you should not be towing a heavy load in 5th, that is a guarantee of a short life for your gearbox.
Drop back to 4th gear and you are right up around 3000 RPM at 100Kmh.

Right back where I said.

If ya want to pull up that hill and do it easily, you'll need to be back a gear or two and be in the 3000 to 3500 RPM range or you will be trying to do it with much less than the available power. ... back at 2500 you will have 2/3 of the available power.

There is little point running over 3500 because the power drops off before the 4200 redline ... just like I said.

If your Prado is running out of puff at 3000 RPM, I'd be looking for an intake restriction, blocked up injectors, carbed up rings or some other problem ..and they get that way if you baby them ........ it should be pulling willingly all the way to 3500.

cheers
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Follow Up By: Ron N - Saturday, Jul 29, 2017 at 17:56

Saturday, Jul 29, 2017 at 17:56
The OP is not talking about a Prado, he's talking about his 2011 Hilux.

The D4-D, 1KD-FTV engine comes in numerous states of tune, according to vehicle fitment - not just "target market and emissions specifications" - and the 1KD-FTV engine in the Prado has a different state of tune to the 1KD-FTV engine in the Hilux.

The Hilux engine produces maximum torque from 1400RPM - not 1800RPM.
1800RPM is the commencement of the maximum torque for the Prado engine.

I was brought up with a very basic diesel operation principle since I started operating diesels at 16 in 1965.
If you are lugging a diesel under heavy load, that's O.K. But if you are indulging in engine lugging, whereby the engine RPM does not increase with the application of more throttle, then that style of engine lugging is extremely life-shortening to a diesel engine, and you need to reduce the load on the engine.

That mantra has been utilised by myself and everyone I have trained in the use of diesels, since 1965, and I've never destroyed a diesel engine by overloading, yet.

As regards your talk of "power", I was under the impression we were talking about Torque.
HP or Kw is what you are confusing with torque - because HP or Kw is the speed at which the work is being done.
Torque is the level of twisting force being applied to a shaft.
Torque is the measurement from which HP or Kw is calculated - because HP or Kw is the RATE at which the work is being done - and Torque is the engines ability to carry out the work.

Hilux 1KD-FTV torque curve
Cheers, Ron.
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FollowupID: 883124

Follow Up By: The Bantam - Saturday, Jul 29, 2017 at 22:52

Saturday, Jul 29, 2017 at 22:52
Read my original post again ...... read my recent post again.

I am perfectly aware of what torque and power are and their relatiuonship.

The unarguable fact remains ...... if you are trying to pull a load at 2500RPM, you have 2/3 of the power available at 3500 RPM.

The OP was concerned about the lack of power.

People all to often bang on about torque ..... it is "power" that does "work" .... it is power that moves the vehicle along the road, it is power that pulls the trailer up the hill.

If you want to get the job done, go back a gear and get the revs up and get more power. ..... and probably use less fuel doing it.

cheers




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FollowupID: 883127

Reply By: Member - graeme W (WA) - Saturday, Jul 22, 2017 at 16:13

Saturday, Jul 22, 2017 at 16:13
Hi Dean. I don't think you actually said how many litres per hundred you are using. I tow a 1900kg coromal poptop with a 2005 crd hilux. I get between 13 and 16 litres per hundred depending on wind conditions at 95klms per hour. Manual gearbox in 4th gear. Cruise control is not used if its hilly. At 90klms per hour its a bit better.I use an oiled sock in the snorkel and clean it regularly. It is amazing how much crap and dust it collects. I have done comparisons with and without the sock and there is no difference in fuel consumption , the only result without is a dirty air filter. I tested my speedo the other day and I am actually doing about 97klms per hour so I will back it off a bit. My hilux has done 250,000 klms and the injectors are original. May have been a bit lucky with fuel quality but I change filters often and oil and filter never go more than 8000klms. Often here other people with big vans and double cabs talking 19-20 litres per hundred.
cheers Graeme.
AnswerID: 612667

Follow Up By: Member - wicket - Saturday, Jul 22, 2017 at 20:00

Saturday, Jul 22, 2017 at 20:00
250k on original injectors, must be some kind of record ! Just wondering if you have a secondary fuel filter fitted and or a catch can ?
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Follow Up By: Member - Wildmax - Saturday, Jul 22, 2017 at 21:00

Saturday, Jul 22, 2017 at 21:00
I've done around 180,000km, mainly towing and lots offroad, in our 09 manual Hilux, and it's performed faultlessly.
Injectors are original, and apart from paying close attention to normal maintenance (filter changes etc) there has not been any issue.
Not the quickest beast off the mark, but driven properly it's a great vehicle.
Wildmax
2018 Hilux pulling AOR Eclipse
Black Wolf 210 tent

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Follow Up By: Member - graeme W (WA) - Saturday, Jul 22, 2017 at 21:28

Saturday, Jul 22, 2017 at 21:28
Hi Wicket. Its not fuel that wears them out its the crap in the fuel mainly water, i dont have an extra filter (will be the first thing fitted on a new one though) but i always pump a bit of fuel out into a plastic container each oil change. Any water in it and i change the filter. I will bet that lots of hilux owners have been had regarding injectors. The first crd hilux up to when they upgraded the engine (at least till then i was only concerned with mine) had a problem with the orings on the injectors. When a hilux was parked facing slightly uphill oil from the engine would leak pass the injector into the combustion chamber, when started they would blow smoke and rattle till the oil was burned off. That was what mine was doing, i rang our local dealer and by chance got the service manager who said, i bet you park uphill at night, which i did. Long story but fixed by 4 orings. They did a recall on some models it was that bad. A lot of injectors replaced as well by other service places without need.
Cheers Graeme
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Follow Up By: 9900Eagle - Sunday, Jul 23, 2017 at 05:33

Sunday, Jul 23, 2017 at 05:33
Bosch and others makers like delphi state their crd injectors are good for a Billion operations, which is the life of the vehicle, as said it is contaminates in the fuel that wear them out.
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FollowupID: 883019

Follow Up By: Ron N - Friday, Jul 28, 2017 at 20:18

Friday, Jul 28, 2017 at 20:18
I defy anyone to provide written proof from a diesel injection shop, that their 250,000km injectors are still providing "as-new" performance, by way of perfect injection spray pattern and (internal) leak-free operation.

Correct injector spray pattern is crucial to a diesel's economy. The injector spray pattern is affected by wear of the moving components, erosion of the injector spray orifice/s by tiny dirt and water particles (keeping in mind that 2 microns is the average filtering ability) - and by carbon build-up on the injector tip, caused by the burning of thousands of litres of fuel over multiple years.

The old, mechanical-style injectors had one moderate-sized orifice, and did one injection spray on each firing stroke.
Todays CR injectors have between 4 and 8, much tinier orifices, in the tip, and they carry out "pulsed injection", meaning up to 5 injection pulses in the one firing stroke.
This simply means todays CR injector is working a lot harder, and has much more potential for the tinier spray orifices to block up with carbon - and they have less allowance for erosion wear in the orifices.

Cheers, Ron.
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Follow Up By: 9900Eagle - Sunday, Jul 30, 2017 at 08:02

Sunday, Jul 30, 2017 at 08:02
Ron, see you have been talking about cummins engines elsewhere in this post. I know first hand of 3, 600hp speced CRD ISX engines that didn't have their injectors changed until just short of 800000K. They were only changed as they were coming to end of their life and not because of any problems.
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FollowupID: 883130

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