Automatic transmission behavior

[Parabellum9095]

The automatic shifting in this game is bogus. I'm driving a Pete 389 with a Cat C15 625hp/2,050ft-lbs engine and the Ultrashift 18-speed, settings are real automatic with adaptive automatic on normal. It revs a touch above 1,500rpm and skips as many gears as possible for every shift, no matter if I'm bobtail and barely touching the accelerator or 100k lbs gross weight and pedal to the floor up a hill. I'll be trying to accelerate up a hill, probably because the AI traffic slowed me down, and it will rev to 1,500, skip 2 gears and drop me near 1,000rpm lugging the engine, then a second later drop a gear and finally put me in the power.

I watched a video demonstrating an Ultrashift 18-speed that showed that it will rev over 1,500 with the pedal on the floor, but under normal driving will happily shift well before 1,500 if it doesn't need to rev all the way up, and it won't skip so many gears if you're really on the go pedal. The different adaptive automatic modes don't seem to have much effect, except that power mode makes it want to rev closer to to 2,000 before shifting.

Is there any setting or mod I could play with that will make the game version behave closer to the real thing? I believe the shift points are programmed into some file, so if someone had good settings I could just modify that file, too. Thanks.

[Trucker_71]

Bind a key to switch to sequential shifting. That way you can make it stay in a preffered gear as you climb hills etc., then switch back to real automatic when you're ready to let the truck do the shifting.

[room217au]

It is code and will never be exactly how it is in real life, I'm afraid.

[Fury6]

Shift settings for tuning automatic shifting behaviour is set in the engine definitions. The defaults for these are generally a little suspect. Taking a look at the C15-625 specifically:

	rpm_range_low_gear: (800, 1500)
	rpm_range_high_gear: (1000, 1400)
	rpm_range_power: (1550, 2100)

it seems the shift range upper value for the low gear range is a little high at 1500 and weirdly actually lower at 1400 for high gear range. This might be why your unloaded behaviour is a little strange with the upshifts. I don't use automatic shift modes myself so I can't say for sure, however tweaking those upper values might get better results here.

The power range seems to be ok though so the issue with loaded up and pedal to the floor must be entirely with the adaptive mode itself, which is hardcoded.
--

[NOTE: I'm going off memory here and it's been a long while since I last checked these definitions off the modding wiki]
The way these RPM ranges work is: The first (low) values in each set represent the downshift RPM, the second (high) values represent the upshift RPM. The 'rpm_range_low_gear' set represents the gearbox's low-range gears while the 'rpm_range_high_gear' set represents the gearbox's high-range gears.

The 'rpm_range_power' set represents the respective down/upshift RPM for when the autoshift system detects a high engine-load condition (eg. loaded up and/or hard on the accelerator).
--

This is my own engine definition that I use for my own C15-625 engine:
file: catc15_625.sii

SIINunit {
    accessory_engine_data: c15_625.f6.kenworth.w900.engine {
    	name:               "Caterpillar C-15 625 - fury6"
    	price:              53490
    	unlock:             18
    	info[]:             "625 @@hp@@ (466 @@kw@@)"
    	info[]:             "2@@dg@@050 @@lb_ft@@ (2@@dg@@779 @@nm@@)"
    	info[]:             "1@@dg@@000-1@@dg@@500 @@rpm@@"
    	icon:               "engine_cat_c15"

    	volume:             15.2
        consumption_coef:   1.0

    	torque:             2779
    	torque_curve[]:     (0,     0)
    	torque_curve[]:     (300,   0.185)
        torque_curve[]:     (500,   0.65)
    	torque_curve[]:     (1000,  1)
    	torque_curve[]:     (1500,  1)
    	torque_curve[]:     (1700,  0.94)
    	torque_curve[]:     (2100,  0.74)
    	torque_curve[]:     (2400,  0)

        secondary_torque:               -1
        secondary_torque_gear_ratio:    1.0
        secondary_torque_curve[]:       (0,     0)

        resistance_torque:      -1

        rpm_idle:               650
        rpm_limit:              2100
        rpm_limit_neutral:      3000

        rpm_range_low_gear:     (900,   1350)
        rpm_range_high_gear:    (1000,  1650)
        rpm_range_power:        (1550,   2100)
        rpm_range_engine_brake: (1350,  2100)

        engine_brake:           2.0
        engine_brake_positions: 3
        engine_brake_downshift: false

        adblue_consumption:     0
        no_adblue_power_limit:  1.0
@include "sound.sui"
        }
}

You could use this, if you wish, to add an extra C15-625 engine for tweaking those rpm ranges. I've already tweaked them a little myself but as I said above I don't actually use the automatic modes so it's been a long while since these values have been tested at all.

To use it, create a directory tree in the ATS mod directory as per:

<whatever name you like>\def\vehicle\truck\peterbilt.389\engine

then copy & paste the engine definition above to a file inside that final directory, give the file whatever name you like that doesn't conflict with any existing engine name - my suggestion would be 'catc15_625.sii' - OR - you could flat out replace the existing C15 625 engine (the SCS default one) with the filename 'catc15.sii'.

If you use the in-game console, you can edit the file on the fly by making your edits, then entering the command 'game' into the console to reload the profile and propagate the new values into the game. If you're not using the console then you'll just have to quit out to the profile manager and reload the profile manually for the changes to appear in-game (you can make the edits at any time though, even while still in-game).
--

As I noted above however, the actual adaptive shift behaviour is hardcoded into the mode, so as room217au notes things won't ever be quite as per real-life without changes from SCS's end. I can't guarantee that you'll achieve anything better than you have, but it's available in case you might want to try and Trucker-71's suggestion is a pretty effective workaround given the above.

[Parabellum9095]

Originally posted by Trucker_71:

Bind a key to switch to sequential shifting. That way you can make it stay in a preffered gear as you climb hills etc., then switch back to real automatic when you're ready to let the truck do the shifting.

I have buttons on my gamepad bound to shift hint up/down, which works mostly ok without needing an additional button for switching shift modes.

Originally posted by Fury6:

Shift settings for tuning automatic shifting behaviour is set in the engine definitions. The defaults for these are generally a little suspect. Taking a look at the C15-625 specifically:

	rpm_range_low_gear: (800, 1500)
	rpm_range_high_gear: (1000, 1400)
	rpm_range_power: (1550, 2100)

it seems the shift range upper value for the low gear range is a little high at 1500 and weirdly actually lower at 1400 for high gear range. This might be why your unloaded behaviour is a little strange with the upshifts. I don't use automatic shift modes myself so I can't say for sure, however tweaking those upper values might get better results here.

The power range seems to be ok though so the issue with loaded up and pedal to the floor must be entirely with the adaptive mode itself, which is hardcoded.
--

[NOTE: I'm going off memory here and it's been a long while since I last checked these definitions off the modding wiki]
The way these RPM ranges work is: The first (low) values in each set represent the downshift RPM, the second (high) values represent the upshift RPM. The 'rpm_range_low_gear' set represents the gearbox's low-range gears while the 'rpm_range_high_gear' set represents the gearbox's high-range gears.

The 'rpm_range_power' set represents the respective down/upshift RPM for when the autoshift system detects a high engine-load condition (eg. loaded up and/or hard on the accelerator).
--

This is my own engine definition that I use for my own C15-625 engine:
file: catc15_625.sii

SIINunit {
    accessory_engine_data: c15_625.f6.kenworth.w900.engine {
    	name:               "Caterpillar C-15 625 - fury6"
    	price:              53490
    	unlock:             18
    	info[]:             "625 @@hp@@ (466 @@kw@@)"
    	info[]:             "2@@dg@@050 @@lb_ft@@ (2@@dg@@779 @@nm@@)"
    	info[]:             "1@@dg@@000-1@@dg@@500 @@rpm@@"
    	icon:               "engine_cat_c15"

    	volume:             15.2
        consumption_coef:   1.0

    	torque:             2779
    	torque_curve[]:     (0,     0)
    	torque_curve[]:     (300,   0.185)
        torque_curve[]:     (500,   0.65)
    	torque_curve[]:     (1000,  1)
    	torque_curve[]:     (1500,  1)
    	torque_curve[]:     (1700,  0.94)
    	torque_curve[]:     (2100,  0.74)
    	torque_curve[]:     (2400,  0)

        secondary_torque:               -1
        secondary_torque_gear_ratio:    1.0
        secondary_torque_curve[]:       (0,     0)

        resistance_torque:      -1

        rpm_idle:               650
        rpm_limit:              2100
        rpm_limit_neutral:      3000

        rpm_range_low_gear:     (900,   1350)
        rpm_range_high_gear:    (1000,  1650)
        rpm_range_power:        (1550,   2100)
        rpm_range_engine_brake: (1350,  2100)

        engine_brake:           2.0
        engine_brake_positions: 3
        engine_brake_downshift: false

        adblue_consumption:     0
        no_adblue_power_limit:  1.0
@include "sound.sui"
        }
}

You could use this, if you wish, to add an extra C15-625 engine for tweaking those rpm ranges. I've already tweaked them a little myself but as I said above I don't actually use the automatic modes so it's been a long while since these values have been tested at all.

To use it, create a directory tree in the ATS mod directory as per:

<whatever name you like>\def\vehicle\truck\kenworth.w900\engine

then copy & paste the engine definition above to a file inside that final directory, give the file whatever name you like that doesn't conflict with any existing engine name - my suggestion would be 'catc15_625.sii' - OR - you could flat out replace the existing C15 625 engine (the SCS default one) with the filename 'catc15.sii'.

If you use the in-game console, you can edit the file on the fly by making your edits, then entering the command 'game' into the console to reload the profile and propagate the new values into the game. If you're not using the console then you'll just have to quit out to the profile manager and reload the profile manually for the changes to appear in-game (you can make the edits at any time though, even while still in-game).
--

As I noted above however, the actual adaptive shift behaviour is hardcoded into the mode, so as room217au notes things won't ever be quite as per real-life without changes from SCS's end. I can't guarantee that you'll achieve anything better than you have, but it's available in case you might want to try and Trucker-71's suggestion is a pretty effective workaround given the above.

I'll try editing the engine file here in a minute. Just to be clear, I would have to turn adaptive automatic OFF to have any changes I make take effect, yes?

My kingdom for a wheel and shifter. I'm only using real auto mode because I don't have one. Soon as I get one I'll be jamming gears in the ol Pete and shifting when and how I like.

[Fury6]

Originally posted by Parabellum9095:

[...] Just to be clear, I would have to turn adaptive automatic OFF to have any changes I make take effect, yes?[...]

Not necessarily. You'd have to experiment for yourself which behaviour you prefer, as I said I don't use the automatic modes so my experience with them is well and truly out-dated.

[Parabellum9095]

It took me 3 hours to figure it out, but I ripped the catc15.sii file from dlc_peterbilt_389.scs and made a mod version of the engine which changes the shift points. Specifically,

rpm_range_low_gear: (900, 1350)
rpm_range_high_gear: (1200, 1500)
rpm_range_power: (1350, 1750)

I did a quick test and it definitely works and feels better to use. There are a few notes I'd like to add though, in case this thread pops up on anyone else's radar in the future:

1) Adaptive automatic seems to act like a modifier to shift behavior. My changes work with adaptive automatic, but the 3 modes, seemingly including eco mode, always rev slightly higher than the .sii file values. Power mode revs much higher and also seems to raise the downshift values.

2) rpm_range_power only comes into effect while both towing and accelerating up hill. 100% accelerator, loaded or bobtail, on level ground has no effect. 100% accelerator bobtail uphill has no effect. It will only rev over the normal shift points for low or high range when towing uphill with high percentage of throttle applied.

Thank you very much, fury6, for helping me make my first mod. Cheers.

Edit: rpm_range_power also disengages as soon as you reach level ground. If you're revving 1,600 on the hill and reach the top, it will immediately upshift as many gears as possible regardless of throttle position.