14MY PC "Learning Auto"

[robdavo]

OK guys. I have only done a little over 3000km in my PC auto, and I only drive it occasionally as my wife has it most days. My big concern is the adaptive auto, as I find it seems to do strange things like change down on the smallest of hills, stay in a lower gear whilst cruising down a hill, not change up on the flat until I back off the throttle a bit etc. etc.
Could these be explained because the auto is trying to adapt to 2 different style drivers, or do I just need to get used to an auto?
Also, is a reprogram of the auto possible to remove this adaptive learning, and set it to sports mode for instance?
Is there any way to have the gear indicator on the dash show what specific gear it is actually in whilst in auto (rather than show D) similarly to that shown when in manual mode. Will a scan gauge or similar do this?
Finally, does anybody have the figures for the rpm/kph gear change for a stock PC base 16" wheels. The only way I can get an idea if the auto is hanging onto a gear a bit too long, or too early is by knowing the rpm's at a particular speed.

[shadowarrior]

Even though my car officially belongs to the Mrs, I do the driving mainly. I am quite happy with the adaptive learning. My14 PC just shy of 5000kms.

90% of the time around the city or around traffic, I let it stay on D. Other times I only interfere with it's 4th and 5th gear. For example during my recent trip when I was driving from Nowra to Batemans Bay, the auto controls wanted to shift to the 5th. Rain and the sweeping turns, I felt comfortable sitting on 4th. So manually selected 4th and let it sit there. As soon as I was entering a town, I would cancel manual selection.

Through out my highway driving between Sydney to Gold Coast, I let it manually sit at 5th 100-110kmph and only shift to 4th for overtaking someone. Enter a city or 40 construction zone, I changed it to auto select.

For my daily driving around the city to and from work, I usually let the gearbox decide 1st, 2nd and 3rd. If I am entering freeways, I over ride the 4th and 5th selector again.

I have noticed the Auto mode to shift down a gear for any uphill, even if its a small crest.

If I am accelerating hard from stop, (60 zone to 80 zone to 100 zone within 1 km) I have noticed it holds the 4th longer while spooling till I let go of the accelerator for a second after I reach the 100 limit. Re applying the accelerator then shifts to 5th.

I think the owner's manual has a guide for speed and rpm range for each gear. I am guessing the adaptive system works off that. I am convinced that different driving styles affect the adaptive gear shifts though. The test drive car we had, we hated the adaptive shift. It was kind of too low. The new one took a month's driving and it now kind of shifts when I would usually shift on my manual.

[old Jack]

Hi Dave,

The auto trans in the PB/PC is at it's design torque limit and this is why the engine has been detuned mid range so torque is capped at 350Nm. The Torque Convertor has a stall ratio of 2.04:1 so it is a high slip TC, this is great off road and when starting off on a steep gradient when fully loaded but in normal driving it is like driving a car with a CVT. The AT ECU is poorly programmed and the Adaptive Learning function makes the whole drive experience worse. I find if I drive in "D" all the time the car becomes a "fuel sucking slug" due to the adaptive Learning and the AT changing up to early so the engine labours. If you drive in Sports Mode regularly the adaptive Learning tends to "reset". I am currently working on a way to "disconnect" the AL and or limiting 5th gear changes to only over 70kph rather than 50kph.

Unfortunately the shift selector does not always indicate what gear the trans is in but the highest gear you have selected so the display can be "4" and the trans is actually in 3rd and the only way to know this is by speed and rpm. The shift display will not change down until 2nd gear is automatically changed and even then the display will say "3" this will not change until you have slowed down and the trans has automatically changed to 1st and at this stage the display reads "1"

I do not think there is a way to get the shift indicator to display the actual gear the trans is in when driving in "D"

To give you an idea of when the TC is in a "no slip" condition the following applies in theory with standard diameter tyres,
2nd 40kph 2200rpm no slip, any higher rpm at this speed and the TC is slipping.
3rd 60kph 2280rpm no slip, any higher rpm at this speed and the TC is slipping.
4th 60kph 1610rpm no slip, any higher rpm at this speed and the TC is slipping.
If you find the TC slipping and "not catching up" try keeping the trans in a lower gear and delay the upshift until you are at 2500rpm and have been at those revs for at least 30 seconds after there has been no increase in speed for the 2500rpm setting.

Some further reading that may be of interest:

http://www2.pajeroclub.com.au/forum/showthread.php?t=36892

http://www2.pajeroclub.com.au/forum/showthread.php?t=35928

cheers, old Jack.

[robdavo]

Thanks Shado and OJ
This is my 4th 4wd, the other 3 being manuals, as were nearly all of my previous cars. Still coming to grips with an auto again, and do use the manual (especially the paddle shifts which I love) quite a lot, especially when off road, but also a bit like Shado uses his. Appreciate the info on the rpm/kph and the links to your previous posts OJ (had found them some time ago, but couldn't re-find before this posting), and I will restudy the detail. I assume that all reference to "sports mode" means in manual override as opposed to auto. Will keep monitoring this forum to see if you find a solution to the AT ECU program, and I will talk to MMA when I drop her in for a 7500km service prior to going away for 6 weeks towing a van, to see if they can disable the learning and "lock" the auto into effectively a standard auto mode.
Bottom line from all this seems to be that the only real way to tell what gear you are in whilst driving in auto mode is by looking at rpm and speed, and relying on the aural senses.

[momo]

If I had the money I would have installed a custom low-stall TC yonks ago.
Perhaps some tweaking can be done via the transmission ECU but no-one hacks it aftermarket like the engine ECU unfortunately.
The Challenger is my first auto and it has taken me a long time to accept the way it behaves, we wanted a manual but of course they were rare so we settled for the auto instead.
I'm pushing close to 600NM through it so at least it has held up to that. I just wish it could drive under 3000rpm, I showed videos to auto transmission specialists and they couldn't believe how it would sit on 3k from 40-110kph like a CVT.

[old Jack]

600Nm do tell more?

cheers, old Jack.

[auskenny]

600Mn sounds very interesting

[momo]

I think it was 580 from memory. Just a dyno tuned Chip-it with the fuel rail mod. I use the switch to change between custom maps so it doesn't spend much time at that power level (can someone say smokey )

[littleriver]

I think it was 580 from memory. Just a dyno tuned Chip-it with the fuel rail mod. I use the switch to change between custom maps so it doesn't spend much time at that power level (can someone say smokey )

would like to see the dyno chart print out if you have it

[momo]

Not sure I could find it in a hurry. I had posted it over at newtrition.net and what a shit fight that caused at the time. I just looked there (last visit 2011 ) and as I thought all the threads were deleted because someone got their knickers twisted over it.

[old Jack]

Dyno charts are only a useful before and after comparison and are dependant on the dyno and the operator.

The factory chart is measured at the flywheel where as a dyno is measured at the rear wheels/hub so you tend to get kW/power losses of about 30% at the rear wheels but an increase in torque due to the final drive ratio of the diff. Automatics give a more distorted graph if the measurement is taken at the rear wheels due to the torque multiplying effect of an automatic transmission's torque convertor.

Factory Chart, the green line is the auto's power curve (calculated and plotted);


MRT Dyno Chart;


MRT Dyno chart;


MRT Dyno chart;


MRT Dyno Chart;


As you can see there are 4 different MRT Dyno graphs for the 4D56 CRD engine and 4 different results.

cheers, old Jack.

[momo]

Here it is, dug it from out from some dusty place.

I agree it's not the best presented graph :

[momo]

As you can see the power plot comparison is very telling, however my understanding is that only torque is measured and power is calculated from the torque results. At least the power plots show whats happening higher in the rev range well after TC lock-up. This my first auto that I've had dynoed and I could see how hard it is to capture torque results at lower revs because that F'n TC shoots the revs up so fast.

Still a healthy % increase at 2500rpm, and with all factors considered I am calculating definately over 500Nm

Either way, I have nothing to boast about so if you said it was 386Nm I wouldn't care .

[littleriver]

very impressive dyno results

[Tone13]

I've just bought a 2012 XLS (I pick it up in 2 days, woohoo!)
Was originally looking at Pathfinders and liked the fact they had plenty of torque (450Nm) but at the same time heard that a 2.5 lt engine pushing out that much torque will likely lead to decreased engine life and reliability issues.
The Challenger came up and I decided to go for it as the reliability of the Pathfinders seems questionable and the challenger still has three years mitsubishi warranty left on it not to mention being a proper 4x4 with rear diff lock and good wheel articulation unlike the Pathfinder.
Anyway, Didn't really want an auto but that's all that is available in the XLS. I knew beforehand that the auto is de tuned to 350Nm but it's still a little disappointing so iam thinking about a Ecutek remap once I pick the car up next week.
My question is, considering that Mitsubishi feels the need to def tune the engine down to 350Nm to protect the auto box, aren't you guys pumping up the Nm over 400Nm worried about what that will do to the transmission?

Isuzu has a great reputation for their Diesel engine and they limit the torque to their 3.0lt engine to 380Nm to under stress the engine and get rock solid reliability and very long engine life.