Problem with towing - Mit Challenger

[old Jack]

Thanks Ent, yes MM do over state towing capacity but I suspect they are not the only manufacturer.

SA towing regulations are;
Trailer braking regulations:
• Trailers must be fitted with brakes if the GTM exceeds 750 kg.
• Over-Ride/Over-Run brakes are acceptable up to a GTM of 2 tonnes.
• Where the GTM exceeds 2 tonnes the braking system must be fitted with a breakaway system that causes the brakes to be applied if the trailer becomes disconnected from the towing vehicle.

Yes, I have been a naughty OJ but speeds in the suburbs were only up to 60kph and I left lots of braking room and no signs of being under braked. Trailer was rated to 2,000kg and had over-ride hydraulic brakes that worked really well and the load sharing rocker style leaf springs hardly dropped with the load. Higher speeds up to 80kph were done for only about 5kms uphill then I was going up a steeper hill so no chance of being under braked due to load. Trailer tub was only 2.4 metres long + 1.8 metre draw bar and lower than 900mm high so the centre of gravity was low and the moment (leverage that could be applied to the rear of the car) was very low and no wind forces were involved. A calculated illegal risk that would have voided my insurance, I know. Promise I won't do it again.

cheers OJ.

[Ent]

Ha ha, sorry was not having a go. Just was hoping that you had checked out an electronic braking system. In my dreams I am toying with a caravan holiday but past a tonne with my safety first mindset I would fit the best braking system I could find.

The biggest issue with towing with a manual is reversing up a slope as DooSo struggles doing this with no load. Watching the low range 2wd modifications with interest. Was tempted to try what you did to see how DooSo would handle the task.

Generally once DooSo is past 2000 rpm I find enough power and torque. With a sensible down weight I think my rear suspension could cope but again watching load equalisation hitch threads to get some idea of the best way of doing things.

Apart from unbraked trailers (lets not argue that 1.5 tonne is safe as I know it is not) with other vehicles I have done no serious towing. So reading with interest people's experiences.

[robdavo]

Just a question on clarification of driving in "manual" or "sports" mode in the auto.
The auto can be switched into manual by either shifting the selector across to the manual position, and then changing up/down using the gear selector lever, OR the paddle shifters.
Alternately, you can leave the gear lever in the Auto position, and just use the paddles.
I think that the main difference in whether in "manual" mode, or "auto" mode and using paddle shift, is that the box will revert to full auto when you stop if, I think, using just the paddles; that is, with gear selector still in auto.
Does the term "sports" mode also mean selecting "manual" by either one of these methods, or a specific method?
Apart from this, is there any difference towing wise (or gear holding for instance) between the two methods of manual selection?
Mostly when towing, I let the auto look after itself, and generally find this to be satisfactory. I only select manual mode via the paddles for either prolonged uphill / downhill, or steeper grades where I consider a loger gear necessary to maintain speed etc. So far I have not noticed any change in dash guage temperature increases, nor limp mode activity in using full auto. Also fuel economy is still acceptable, and even using cruise control seems to provide better economy than not using it. As posted on other threads, my average fuel consumption over a 6000km trip recently (approx 5000km towing) from Melb to S.Aust Yorke Peninsula via Coorong, and back through the hills to Mt Remarkable etc, gave an average of 13L/100Km, which I am more than happy with.
I have also noticed that the box will still act in an auto fashion (change down gears, not sure about upshift ) when effectively manual has been selected by the paddles.
Any worthwhile comments appreciated

[s1rx]

OJ,

Why not use a jaycar digital pulse adjuster & hand controller, load resistor to the correct resistance to the solenoid( 20ohm or thereabouts? Alloy wound type with heatsink type looking at the WA website) & toggle switch for the dcc solenoid control on the tranny?

The only painful part would be programming. As i can see looking at the wholesale auto kit thats all it is except they have duty maps dedicated to the given solenoid for that transmission type.
The only real advantage to doing this is how much you can really tweak the system to your requirements.

Or just buy the wholesale autos kit might be the answer for an extra $250 odd and save a lot of the grief?



Just had a jaycar voltage modifier kit arrive a few weeks back which i intend to manipulate the map sensor voltages with & attemp to get around the cel issues i have. I have to clamp down the sensor voltage so much(cel on extended full throttle pulls otherwise) which takes away a sizeable % of the injector duration on the factory mapping. I then need to dial my steinbeaur right up to compensate which i dont like. So hopefully with a bit of (or a lot of ) voltage manipulation across a wider range Im able to generate a more stable and similar voltage map back to the ecu to fool it!

Note: It will prob take many weeks to achieve this goal & in hindsight perhaps it would have been easier to flash the ecu knowing all the finicky adjustments id like made to the fuel & boost mapping... why do we get ourselves in these predicaments to save a few bucks or maybe in my case because i dont trust to many self proclaimed tuners and like the ability to adjust parameters & not be locked into 1 option only!

[old Jack]

Hi sr1x,

Yes I have looked at buying a TC lockup over ride from Wholesale Automatics or even building on myself, but either of these require manual operation and only go part way to solving the autos programming issues.

Similarly I have also looked at modifying sensor signals to "fool" the AT ECU into doing things but I need to both increase and decrease signal strengths on each sensor so this very difficult to do.

Far better solution is I have a spare AT ECU and I get the desired "switch points" changed to solve the poor programming. I want to modify the up and downshift points and also TC dampener control solenoid at various throttle settings, engine rpm and vehicle speeds.

cheers, OJ.

[02-SR5]

Apparently a ECUTek is the way to go. They programme both engine and gear box. A dude on FB reckons he has 500nm now with this tune. Costs about $1500. Same price as a DP chip.

[s1rx]

Yes the ecuteks are good. A full wire in ecu is even better!

That is easily acheived.I would be easily over 500nm and probably into the mid 550nm range. If i turned the dial up to 26psi plus 600s could be netted. The great thing about the 4d56t is how well matched the IHI turbo is to the engine. You really have to drive a well tuned car to appreciate it.

I have tweaked quite a few diesels over the last 12 months for mates including a variety of chips and setups on different CRD cars. It isnt hard to get some nice gains from cars but quite essential to do it correctly too.

Ive worked out 2 methods now to increase boost pressure which covers any CRD (even the elec controlled turbo setups)+ when combined with a inj timing chip nets gains equal too or better then $2000 flashed ecus for less then half the price by using good 2nd hand units or retain current chips installed if correct type. These mods blow no smoke so run correct fuel ratio, reduce egts, coolant temps give more power & are reliable power + dont strain the injection system like some tuners maps ir chips..
We make sure EGTs are always noted & monitored by the owner + check air intake temps in case a intercooler upgrade is necessary using my budget scan tool lol.

The only pain is ecu fault codes which i get around via the map/maf clamps or in my case the voltage modifier is the next step to see how it goes but wont be setting those up for people as its a pita!

[old Jack]

Apparently a ECUTek is the way to go. They programme both engine and gear box. A dude on FB reckons he has 500nm now with this tune. Costs about $1500. Same price as a DP chip.

I have checked ECUTek's website and they do not list an AT ECU reprogram.

cheers, OJ.

[s1rx]

Hi sr1x,

Yes I have looked at buying a TC lockup over ride from Wholesale Automatics or even building on myself, but either of these require manual operation and only go part way to solving the autos programming issues.

Similarly I have also looked at modifying sensor signals to "fool" the AT ECU into doing things but I need to both increase and decrease signal strengths on each sensor so this very difficult to do.

Far better solution is I have a spare AT ECU and I get the desired "switch points" changed to solve the poor programming. I want to modify the up and downshift points and also TC dampener control solenoid at various throttle settings, engine rpm and vehicle speeds.

cheers, OJ.

For sure OJ. This is the best way to tackle the shortfalls, however, due to the rareness of the vehicle, the cost & the R&D time involved to supply customers a proven/reliable product; really the chances of a business taking it on seems highly unlikely.

The software & equipment outlay isnt worth taking it on yourself & with the release of the new challenger just around the corner, as suspected, any software updates ftom MMA have been almost certainly flushed down the toilet.
Its probably easier to do a whole engine/trans ecu transplant from a nt pajero if you want a better driveline package and auto operation or perhaps pinching it from a wrecked new release triton? Although then you still have a ageing chassis & interior design with a empty back pocket to boot.

Currently we are looking at camper trailers to purchase. Looking at the package we will be loaded to approx 1600kg+ with the boat rack + gear; no doubt when we hit the sandy trails in a hot QLD day, the auto is going to play up like a 2nd hand lawnmower!! It will be a WA lockout, tube & fin alloy secondary cooler upgrade for us if in fact we decide to keep the challenger for this purpose.
Prob sooner trade on something like a petrol v8 cruiser or v8 patrol.