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  #11  
Old 27-02-20
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Originally Posted by penski View Post
I have a lockup kit fitted and would have to agree with you. I thought it was just me. I have set mine conservatively so it doesn't stay locked too low in the rev range but find the engine load and fuel consumption are always higher when towing 2.2t in 5th at 100kph than when i drive with the lockup kit off and shifting to 4th when needed as in the past. It always locks in 4th regardless as confirmed by the RPM. Mine will also stay locked in 5th too when a touch over 100kph in good conditions. I have towed over 10,000 km's now with the kit fitted and trying many different scenarios. Engine load is usually 15% to 20% higher cruising in 5th than 4th.
Hi Penski,

What TC lockup kit do you have fitted?

OJ.
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  #12  
Old 27-02-20
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My 2c: engine load & fuel consumption are related, but there's only a direct correlation in the same gear.

As I understand it, Gen 4 DiD engine load as reported by OBD2 can be thought of as injector duty cycle - how much fuel the injectors are injecting each time, as a percentage of some maximum possible.

So, in any given gear, higher engine load equals higher fuel consumption. But some are also discussing engine load differences in different gears. In 4th gear, at higher revs, the engine may be injecting 20% less fuel than 5th gear in each cycle, but it might also be injecting 30% more often.

On torque pro, I found a fuel flow gauge that reports fuel consumption in litres per hour - only useful when comparing different gears at the same speed, but more useful for fuel consumption comparisons between gears than engine load.

Literally, YMMV.
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  #13  
Old 27-02-20
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Originally Posted by old Jack View Post
Hi Penski,

What TC lockup kit do you have fitted?

OJ.
The MM4X4 as others have fitted here. The kit works exactly as advertised so no issue there. The point I am making is that one of the reasons for getting it for me at least was the ability to cruise along at the speed limit in 5th gear with the TC locked up and getting a fuel economy benefit and cool running transmission. The reality is that fuel consumption remains better for me when towing by using 4th gear which stays locked most of the time without the kit except on a long hill. 5th rarely stays locked without the kit activated when towing. I also fitted an Ultraguage at the same time and would have been just as satisfied to use that to manage transmission temperatures and gear selection using the sports shift. To me the Pajero also operates more smoothly in day to day driving with the kit turned off. Again, mine is set conservatively so maybe I'm not getting the full benefit but I found the defaults far too harsh in normal use.
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  #14  
Old 27-02-20
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Originally Posted by penski View Post
The MM4X4 as others have fitted here. The kit works exactly as advertised so no issue there. The point I am making is that one of the reasons for getting it for me at least was the ability to cruise along at the speed limit in 5th gear with the TC locked up and getting a fuel economy benefit and cool running transmission. The reality is that fuel consumption remains better for me when towing by using 4th gear which stays locked most of the time without the kit except on a long hill. 5th rarely stays locked without the kit activated when towing. I also fitted an Ultraguage at the same time and would have been just as satisfied to use that to manage transmission temperatures and gear selection using the sports shift. To me the Pajero also operates more smoothly in day to day driving with the kit turned off. Again, mine is set conservatively so maybe I'm not getting the full benefit but I found the defaults far too harsh in normal use.
Hi Penski,

Have you tried using the 5th gear lock out mode of Auto Mate?
This gives all the benifets of Auto Mate but prevents the up change to 5th gear, this function was especially designed into Auto Mate for those that tow heavy and use Drive. Auto Mate will keep your ATF temperatures under control, keep you in the correct gear for the load you are towing, and the load the road conditions are imposing and your accelerator pedal input. If you drive using the Sport Shift mode of Auto Mate then you get greater control over gear selection and the blue LED will indicate when the TC unlocks so you can change down a gear and relocate the TC. Auto Mate is reactive to changing conditions as it cannot see the road ahead, so in hilly terrain when conditions are constantly changing, if you drive in Auto Mate Sports Shift mode then you will get better fuel economy and maintain much lower ATF temps.

OJ.
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2011 PB Base White Auto, Smartbar, Cooper STMaxx LT235/85R-16,TPMS, HR TB, 3 x Bushskinz, front +40mm Dobinson , rear +50mm EHDVR Lovells, Dobinson MT struts and shockers, Peddars 5899 cone springs, Windcheater rack, GME UHF, Custom alloy drawer system inc. 30lt Engel & 2 x 30 AH LiFePo batteries + elec controls, Tailgate hi-lift/long struts, Phillips +100 LB & HB, Lightforce 20" single row driving beam LED lightbar, Scanguage II.
MM4x4 Auto Mate, Serial No 1 .
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  #15  
Old 27-02-20
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Quote:
Originally Posted by old Jack View Post
Hi Penski,

Have you tried using the 5th gear lock out mode of Auto Mate?
This gives all the benifets of Auto Mate but prevents the up change to 5th gear, this function was especially designed into Auto Mate for those that tow heavy and use Drive. Auto Mate will keep your ATF temperatures under control, keep you in the correct gear for the load you are towing, and the load the road conditions are imposing and your accelerator pedal input. If you drive using the Sport Shift mode of Auto Mate then you get greater control over gear selection and the blue LED will indicate when the TC unlocks so you can change down a gear and relocate the TC. Auto Mate is reactive to changing conditions as it cannot see the road ahead, so in hilly terrain when conditions are constantly changing, if you drive in Auto Mate Sports Shift mode then you will get better fuel economy and maintain much lower ATF temps.

OJ.
Unfortunately I only have the lockup mate kit, not the auto mate so can't try that feature. Thanks for the info though.
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  #16  
Old 27-02-20
Jasonmc73 Jasonmc73 is offline
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Quote:
Originally Posted by Keithyv View Post
Again, what has this got to do with a lockup kit?
Locking up the TC may enable you to lug along in 5th but it does not mean itís causing any issues, just enabling someone to do it.
I wasn't entering into that

Just merely agreeing to the obvious.

My comment is nothing to do with lockup kits

Towing 2.2 tonnes in 5th gear in lieu of 4th gear highly likely to use more fuel.

4th gear at lets say 90k's per hour you may very well find will use less fuel & less engine load.

Does the vehicle manufacturer in the operators handbook give any tips?

Not always but sometimes the instructions can be helpful although often we don't read them of course.
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  #17  
Old 27-02-20
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Quote:
Originally Posted by penski View Post
Unfortunately I only have the lockup mate kit, not the auto mate so can't try that feature. Thanks for the info though.
Ok, Lockup Mate operates the same as the Sports Shift mode of Auto Mate so you should be able to use this and just not change up to 5th.

OJ.
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2011 PB Base White Auto, Smartbar, Cooper STMaxx LT235/85R-16,TPMS, HR TB, 3 x Bushskinz, front +40mm Dobinson , rear +50mm EHDVR Lovells, Dobinson MT struts and shockers, Peddars 5899 cone springs, Windcheater rack, GME UHF, Custom alloy drawer system inc. 30lt Engel & 2 x 30 AH LiFePo batteries + elec controls, Tailgate hi-lift/long struts, Phillips +100 LB & HB, Lightforce 20" single row driving beam LED lightbar, Scanguage II.
MM4x4 Auto Mate, Serial No 1 .
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  #18  
Old 28-02-20
Mundy55 Mundy55 is offline
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It seems to me there's a lot of uninformed assertions being made in this thread. I am not sure what people mean by "load" on the engine. For a given speed, theoretically, the work done by the engine is independent of the gear chosen. In practice, the selected gear will determine the rpm which will determine the efficiency point of the engine. The speed and terrain (and drag of your particular tow) also determines the torque demand on the engine and the torque demand also determines the rpm for max efficiency. All of these go to determine the work the engine does and hence the fuel used.

These are complicated interactions and tradeoffs and a blanket statement that 4th uses more fuel than 5th can't be made.

But this work done by the engine is a separate issue to the efficiency of the torque converter and its operating temperature. A locked TC will always operate at a lower temperature than unlocked.

In any event, to me, the primary benefit of the lockup kit is not fuel economy but protection of the TC.
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  #19  
Old 28-02-20
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Quote:
Originally Posted by Mundy55 View Post
I am not sure what people mean by "load" on the engine.
Fair call. I presume they're watching the OBD parameter, which (for the DiD, as I posted earlier) I believe is effectively the duty cycle of the injectors.

Quote:
Originally Posted by Mundy55 View Post
For a given speed, theoretically, the work done by the engine is independent of the gear chosen.
I think this is fair to say, but not 100% accurate. Moving the mass of the vehicle (and trailer, if present) requires overcoming all the various energy-sapping drag forces, like aerodynamic drag, rolling resistance of the tyres, drive train losses. The bulk of this is independent of gear selection, and is effectively constant for any given speed. But drivetrain losses will change depending on gear, and a 1:1 4th gear should have less drivetrain loss than any of the other gears. But these gear selection losses will be very small compared to all the other losses that the engine must overcome.

Quote:
Originally Posted by Mundy55 View Post
In practice, the selected gear will determine the rpm which will determine the efficiency point of the engine. The speed and terrain (and drag of your particular tow) also determines the torque demand on the engine and the torque demand also determines the rpm for max efficiency. All of these go to determine the work the engine does and hence the fuel used.
Yes, many factors determine the amount of fuel an engine is using. Which is why monitoring some of the ECU parameters such as Engine Load and Fuel Flow really helps to understand what's going on.

Quote:
Originally Posted by Mundy55 View Post
These are complicated interactions and tradeoffs and a blanket statement that 4th uses more fuel than 5th can't be made.
Monitoring the OBD Fuel Flow parameter, unfortunately expressed in my Pajero in terms of litres per hour, can help to compare which gear is using less fuel at any given speed. I can have higher "Load" in 5th, but lower "Fuel Flow" than in 4th, because while each injection pulse in 5th might inject more fuel, each injector is injecting less often.

Quote:
Originally Posted by Mundy55 View Post
But this work done by the engine is a separate issue to the efficiency of the torque converter and its operating temperature. A locked TC will always operate at a lower temperature than unlocked.
An unlocked torque converter that is slipping and generating heat is consuming some of the engine's work output. Locking the torque converter will stop the waste of energy, but as you have noted, the engine is likely to be operating less efficiently at lower revs.

Quote:
Originally Posted by Mundy55 View Post
In any event, to me, the primary benefit of the lockup kit is not fuel economy but protection of the TC.
Fair enough.

I think the benefits of a lockup kit depend heavily on how well it is used. Used intelligently, there are significant benefits available, but an intelligent driver can obtain most of those benefits without a lockup kit. Used unintelligently, damage can be done.

MM 4x4's lockup kits have significant intelligence built in, to help protect against unintelligent use.
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NT Platinum. DiD Auto with 265/70R17 Toyo MT, Lift, Lockers, Lockup Mate, Low range reduction, LRA Aux tank, bull bar, winch, lots of touring stuff. Flappy paddles. MMCS is gone!

Project: NJ SWB. 285/75R16 ST Maxx, 2" OME suspension, 2" body lift, ARB 110, 120l tank, bullbar, scratches, no major dents. Fully engineered in SA. NW DiD & auto in place - a long way to go....

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  #20  
Old 28-02-20
markc markc is offline
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"I think the benefits of a lockup kit depend heavily on how well it is used. Used intelligently, there are significant benefits available, but an intelligent driver can obtain most of those benefits without a lockup kit. Used unintelligently, damage can be done."

Good closing statement!

To follow up on my earlier post and reading the replies let me just start with "Its a free country" we are all allowed to establish our own ideas, opinions and have free speech etc. So, on open forums where we can all benefit by everyone’s input let’s do it with respect, an open mind and contribute to the forum in a manner that the forum and pajero 4wd club intended. For myself my trade background and practical hands on experience carries a lot of weight when I assess right from wrong on an engineering basis. Trust me, a degree at university typically 99% of the time doesn't invent something new. It just brings previously discovered principles and physics into the equation to help get it right

So let’s consider what is actually happening with the engine and gearbox at given speed/load/rpm.

Firstly, at a given speed on the same road etc towing an identical load the torque needed at the diff and wheels is always the same regardless of what gear you are in or rpm the engine is doing. The required energy at the wheels must equal the load to maintain the speed. Equal and opposing forces with energy in = energy out.

2nd, the input torque to the gearbox can be different to achieve the needed torque at the output shaft = torque at the diff. I’ll use 3rd @ 1.4:1, 4th @ 1:1, and 5th @ 0.716:1 gears here to explain initially with the torque converter not considered.

In 3rd a lower engine torque and higher rpm is used as the gear box is now giving you a mechanical advantage with a 1.4 : 1 ratio. In this situation, the gear box is providing a reduction not an overdrive so the loading (gear to gear, bearings etc) inside the gearbox is actually reduced when compared to an overdrive situation. In the extreme think of 1st gear in low range, with little engine input there is a huge amount of torque at the back wheels.

In 4th gear the ratio through the gbox is 1:1, in essence the drive is running straight through the box with no reduction. Gears while turning and essentially just freewheeling in the box with almost no load on them or the associated shaft bearings. The engine needs to provide a higher torque at lower rpm than the 3rd gear example above and because of this the internal combustion forces within the engine cylinders are higher but at lower rpm and subsequent piston speeds. The only ratio reduction between the engine and the rear wheel (provided the transfer case isn’t in low range) is the diff ratio (3.692:1) so in essence you could replace the gear box with a straight through drive shaft.

In 5th gear the ratio is an over drive with 0.716 rpm from the engine giving 1 rpm from the gbox output shaft, here the overdrive gears, shaft bearings and engine combustion pressure are at their highest but with reduced engine rpm.

At lighter loads 5th gear and reduced rpm will give the best economy and low engine wear rates, but the key point here is light loads. Remember at 100kph with normal driving and not towing the engine only needs about 15% of available power to maintain speed.

While all of this is designed for with a region of safety margin as the loads go up, component life reduces and in extremes parts can fail quite quickly.

A torque converter does exactly that, it increases available torque just like adding a gear reduction by the flow and shearing of oil but with increased engine rpm. For additional info on how they work see

https://www.youtube.com/watch?v=z5G2zQ_3xTc

Admittedly the converter when unlocked adds heat to the oil and isn’t as efficient as a gear reduction but has the advantage it allows the gearbox to stay in gear, allows the engine rpm to increase to give the extra power needed without an increase in input engine torque and associated combustion pressures. It also gives as a means to not need a clutch like a manual to move off or stay stopped.

Newer gearboxes for the past 15 years have made huge leaps forward including being able to lock up when load, rpm and speed allow and match the “designed” limits of the system all nicely controlled by the transmission computer and other systems within the car that all talk to one another.

While the Pajero will lock the convertor, it will also allow it to unlock if load and conditions need it too. Forcing locking in lower gears is not as significant as the gearbox reductions are helping here but locking in 5th whilst towing is just plain bad on many levels.

Engine output torque required for the same load is increased by 30% 0.716 vs 1:1 with 5th vs 4th, then add to this you are not allowing the converter to unlock and provide another 20% reduction and internal engine loads are now up to give the needed extra 50% torque at the crankshaft. Subsequently combustion pressures needed to achieve this torque are up 50% as are loads on crank and main bearings.

All this extra torque has to be then handled by a gearbox locked in overdrive. Yes the gearbox oil maybe cooler as its not flowing through an unlocked converter but everything else inside the gearbox i.e. gears and shafts are well and truly loaded.

I often wonder why we keep looking for the magic extra piece when what we have has been well and truly engineered over 100,000’s of vehicles and millions of klms of testing at the factory and by us customers in the field. I’m sure if you had a gauge to also read combustion pressure, engine oil temperature and exhaust temperature along with your app telling you about the gearbox temperature you’d be happy to live with a torque converter doing its thing.

With normal Pajero settings and standard gearbox management and a little bit of driver finesse you can have a locked gearbox when cruising 95% of the time with the converter and down shifting helping when needed. Just do what the manual says, leave it in 4th and 4wd with 400 more rpm (approx. 2500 at 95~100kph) you will have cooler gearbox temps, almost no load on the gearbox and significantly lower engine loads. When a hill comes up or loads increase let the converter run unlocked to provide the extra torque needed and drop back to 3rd as required, the loads will be much better compare to 95~100kph locked in 5th and your car will love you for it long term. Fuel wise you may or may not even see a difference with 4th vs 5th when towing, at most it should be less than 1lt/100klm increase and you have the $700 you didn’t use to fund a lock up kit which will cover the extra fuel used in 40,000klm of towing

Apologies that this post ended up a lot longer than I 1st intended

Last edited by markc; 28-02-20 at 06:16 PM.
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