Gearshift Maps

[NiftySVX]

Yeah this needs to happen. bump!

[nsm484]

I am amazed at what people have done, and taking time just to learn and to later on modify the SVX. Bumpers to this, and subscribed as well

[longassname]

Phil,

In response to requests from the Australian side of the globe to port my tcu maps over to the JDM tcu's I did. I think you'll probably prefer to run these maps and let throttle application engage power mode instead of forcing it with the button. Let me know what you think. Here are the plots.

[longassname]

Here's the actual hex for the ECUtune JDM shift maps:

94 JDM norm D 1-2
kph m % throttle
0F 00 80
1E 33 C0
3C 19 F0
53 00 F0
FF 00 FF

94 JDM norm D 2-1
kph m % throttle
0F 00 80
0F 00 C0
2D 19 F0
FF 00 FF

94 JDM pow D 1-2
kph m throttle
14 00 80
23 20 A0
2F 15 B0
40 3C F0
53 00 F0
FF 00 FF

94 JDM pow D 2-1
kph m % throttle
0F 00 80
0F 00 C0
2D 19 F0
FF 00 FF

94 JDM normal D 2-3
kph m % throttle
18 00 80
3C 15 B0
5A 22 F0
95 00 F0
FF 00 FF

94 JDM pow D 2-3
kph m % throttle
18 00 80
3C 0c 9C
50 0C AC
79 1A F0
95 00 F0
FF 00 FF

[b3lha]

Originally Posted by longassname

Phil,
In response to requests from the Australian side of the globe to port my tcu maps over to the JDM tcu's I did. I think you'll probably prefer to run these maps and let throttle application engage power mode instead of forcing it with the button. Let me know what you think. Here are the plots.

Thanks Michael,

My test car was in an minor accident and it's parked up waiting for parts. I will definitely give this a try when I get it fixed. Hopefully soon.

Do you mean Australia or New Zealand? I didn't think there were any JDM cars in Australia. A JDM ROM doesn't work with an Aussie Gearbox because of the VSS2 difference.

I've been trying to get a dump of an Aussie TCU. I suspect it's the same as the UK model. I burned a couple of modified roms for somebody in Aus with the UK rom as a base but I haven't had any feedback yet.

[longassname]

Ya, Harvey was just telling me that it's the UK not the JDM that matches Australian TCU's. I'll do that one now. Sorry to hear your car is banged up.

Originally Posted by b3lha

Thanks Michael,

My test car was in an minor accident and it's parked up waiting for parts. I will definitely give this a try when I get it fixed. Hopefully soon.

Do you mean Australia or New Zealand? I didn't think there were any JDM cars in Australia. A JDM ROM doesn't work with an Aussie Gearbox because of the VSS2 difference.

I've been trying to get a dump of an Aussie TCU. I suspect it's the same as the UK model. I burned a couple of modified roms for somebody in Aus with the UK rom as a base but I haven't had any feedback yet.

[longassname]

I just looked at the uk maps and my us maps will port over to it without modifcation so I'll have it done tonight. I'll post them too.

[b3lha]

I just saw that thread.

Assuming the UK rom will work with an Aussie box, you can pull the 705622 rom from my website. Either the original or my modified version.

For the modified version, I changed the program logic so that "Econ" mode isn't used. The TCU will select Normal if the Econ switch is on and Power if it is off.

I coded that before I figured out how the shift maps work. If I was doing it again, I would just replace the economy maps with your sporty maps and leave everything else stock.

[longassname]

the uk tcu drives in normal mode and switches to power mode under fast, heavy throttle acceleration right? That's what my maps are good for. The original US maps "sucked eggs" and made the tcu's automatic calculation of power mode vs normal mode a liability. My maps make it work like a thing of beauty.

Originally Posted by b3lha

I just saw that thread.

Assuming the UK rom will work with an Aussie box, you can pull the 705622 rom from my website. Either the original or my modified version.

For the modified version, I changed the program logic so that "Econ" mode isn't used. The TCU will select Normal if the Econ switch is on and Power if it is off.

I coded that before I figured out how the shift maps work. If I was doing it again, I would just replace the economy maps with your sporty maps and leave everything else stock.

[longassname]

was more work than i thought but here we go...

[longassname]

and here's the hex for the ECUtune UK shift maps

92 Uk norm D 1-2
kph m % throttle
11 00 80
1E 33 B0
3C 19 F0
57 00 F0
FF 00 FF

92 Uk norm D 2-1
kph m % throttle
0F 00 80
0F 00 C0
2D 19 F0
FF 00 FF

92 Uk pow D 1-2
kph m throttle
12 00 80
2F 16 B0
42 35 F0
57 00 F0
FF 00 FF

92 Uk pow D 2-1
kph m % throttle
0F 00 80
2D 19 F0
FF 00 FF

92 Uk norm 2-3
kph m % throttle
1E 00 80
46 13 BC
5A 1B F0
7A 00 F0
9C 00 F0
FF 00 FF

92 Uk pow 2-3
kph m % throttle
28 00 80
51 0C AC
7E 18 F0
9C 00 F0
FF 00 FF

[b3lha]

Something we haven't discussed so far is how the TCU chooses whether to use Normal mode or Power mode. When you step on the gas, the TCU has to decide whether to stay in Normal mode or switch to Power mode. when you back off a little, it has to decide whether to keep power mode on, or go back to normal mode. I researched this a while ago but never properly documented it. It seems like something that might be fun to modify. By fiddling with this we can make the car more eager to engage power mode on kickdown, or make it keep power mode longer after easing off.

We start off with 4 variables: P, V, O & K.

P (0x00C1). This is the Power mode Timer.

V (0x0018). This is the Vehicle speed in km/h.

O (0x004C). This is the Throttle Opening, a number between 0 and 7. But it's not a linear relationship. The table at location C83C maps Throttle Position% to Throttle Opening. The throttle opening value is used in lots of places in the TCU code, so it probably wouldn't be a good idea to mess with this table.

0000C830   .. .. .. .. .. .. .. .. .. .. .. .. 00 10 16 20
0000C840   30 40 50 60 FF .. .. .. .. .. .. .. .. .. .. ..

The numbers in the table relate to the TPS voltage, 00=0v and FF=5v.

TPS Voltage     Throttle Percent  Throttle opening
0.00 to 0.30    0% to   5%        0
0.31 to 0.42    6% to   8%        1
0.43 to 0.62    9% to  12%        2
0.63 to 0.93   13% to  18%        3
0.94 to 1.24   19% to  24%        4
1.25 to 1.56   25% to  30%        5
1.57 to 1.87   31% to  37%        6
1.88 to 5.00   38% to 100%        7

K (0x0048). This is the Kickdown speed. The rate of increase of throttle. How fast you step on the pedal.

Now we start to look at the logic. When deciding which shift mode to use, the TCU first calculates a variable B:

B is the speed band it is worked out from a table at location C84D.

0000C840   .. .. .. .. .. .. .. .. .. .. .. .. .. 1E 3C 5A

Speed (km/h)  Band
 0 to 29      0
30 to 59      1
60 to 89      2
90+           3

Now the TCU checks whether it is already in power mode. If not, it calculates an index I = (B*4)+(O/2). The Index is used to lookup a table at C850. This table provides a threshold value T. The Kickdown speed is compared to the Threshold. If K > T then the TCU switches to Power mode.

0000C850   96 96 6E 6E 78 78 5A 5A 6E 6E 50 50 64 64 50 50

Speed Band 0, throttle opening 0 - 1, threshold=96
Speed Band 0, throttle opening 2 - 3, threshold=96
Speed Band 0, throttle opening 4 - 5, threshold=6E
Speed Band 0, throttle opening 6 - 7, threshold=6E

Speed Band 1, throttle opening 0 - 1, threshold=78
Speed Band 1, throttle opening 2 - 3, threshold=78
Speed Band 1, throttle opening 4 - 5, threshold=5A
Speed Band 1, throttle opening 6 - 7, threshold=5A

Speed Band 2, throttle opening 0 - 1, threshold=6E
Speed Band 2, throttle opening 2 - 3, threshold=6E
Speed Band 2, throttle opening 4 - 5, threshold=50
Speed Band 2, throttle opening 6 - 7, threshold=50

Speed Band 3, throttle opening 0 - 1, threshold=64
Speed Band 3, throttle opening 2 - 3, threshold=64
Speed Band 3, throttle opening 4 - 5, threshold=50
Speed Band 3, throttle opening 6 - 7, threshold=50

Looking at the table, it is clear that Subaru have not taken full advantage of the flexability available. They have defined the thresholds in pairs. Within each speed band, they have simply pecified a low throttle threshold and a high throttle threshold. The borderline between low and high throttle being 19%.

If you've followed me so far then you will realise that at low speed and throttle, it takes a faster kick to engage power mode. At higher speeds, and with more throttle, a slower kick will do it.

So that is how power mode gets engaged. Now we'll deal with how it gets disengaged.

After calculating B, if the TCU is already in power mode, it uses B to lookup a table at C860. There are 4 entries in the table, two bytes each.

0000C860   02 4B 02 4B 03 32 04 19 .. .. .. .. .. .. .. ..

The first byte of each entry is a threshold A. The throttle opening O is compared against the threshold. If O > A then the second byte gets written to the powermode timer P. The timer counts down and when it gets to zero, the TCU switches back to Normal mode. But while it is counting down, the TCU is continually re-evaluating this condition and resetting the counter. Only when O < A is the counter allowed to timeout.

To explain a bit better, if B=0, then A will be 2 and the timer will be set to 4B. Provided the throttle opening remains greater than 12%, the TCU will keep resetting the timer to 4B and power mode will stay on. Once the throttle opening falls below 12%, the timer will tick down to zero and the TCU will switch back to Normal mode. The values 4B, 32 and 19 represent 3, 2 and 1 seconds respectively. At low speed, power mode will stay on for 3 seconds after you lift off. At higher speed it will be 2 seconds or 1 second if you are doing more than 90km/h.

[longassname]

Very nice. This would be a great way for anyone who wants to start playing with their TCU to start, especially a US owner. You could get at many of the same problems I went after with the shift maps by making the tcu go into power mode instead and this adjustment is much simpler to make. I use the power mode 2 to 1 map (or it's mathmatical equivalent in some instances)for the normal mode 2 to 1 map. This is one of the bigest changes I made and pretty much the same thing could be accomplished by making it very easy to get into power mode at low speed.

[b3lha]

I was just talking to Ron (Needforspeed) about TCU maps and he came up with a fantastic new idea for a mod. No TCU reprogramming necessary.

As I documented earlier, the USDM TCU has some extra shift modes that are controlled by the atmospheric pressure sensor. At low altitude, it uses Normal Mode, at medium altitude it uses LowPres1 mode, at high altitude it uses LowPres2 mode and at very high altitude it uses Power mode.

These modes increase in aggressiveness from Normal, through LowPres1 and LowPres2 to Power.

The sensor resides in the ECU and the signal is carried to the TCU by a wire. The idea is to cut this wire and install a potentiometer or a resistor ladder with a 4 position knob. This would allow the driver to control the aggressiveness of the shifting at 4 different levels. Like a 4 position power mode switch.

The only possible problem I see with this is that the atmospheric pressure signal is also used in the line pressure calculation. I haven't looked into the specifics yet, but presumably it means harder shifts in the high altitude modes. It may turn out to be another advantage of this mod rather than a problem.

[SuberNatural]

I would be very interested in exploring the new option you have mentioned