05-06 DBW Tuning & Map Share

As many of you know, stock drive by wire is very twitchy and very liberal with throttle at even low speeds. I started looking for a more linear map that would be more conservative on throttle, with hopes to improve driveability and gas mileage.

 

Cruise Control specifically is very aggressive on the LegacyGT, it throws you into the seat way too much when your simply trying to add 1mph. Oddly enough my 04 FXT has the same exact DBW map stock, but it's a lot more gradual with cruise control acceleration.

 

Stock Map:

http://legacygt.com/forums/attachment.php?attachmentid=262110&stc=1&d=1519008240

 

New map:

This one is based on NSFW's Target Throttle Plate Position Table with my own Requested Torque Table.

http://legacygt.com/forums/attachment.php?attachmentid=262111&stc=1&d=1519008240

 

With this map the car is less twitchy, and is much smoother, if you want to go faster you press the throttle in more, thus you look less like a boy street racer just daily driving. It's hard to say if it has improved my fuel economy yet though.

 

I'm still studying and logging the stock vs new map function, especially with how cruise control works. Will be posting more updates as I go long.

 

This should make your life little easier to build the table. Top line should stay the same, copy and paste the bottom line of each code section.

 

Version 1 linear map:

Requested Torque (Accelerator Pedal)

0	7.1	14.3	21.4	28.6	35.7	42.9	50	57.1	64.3	71.4	78.6	85.7	92.9	100
0	75	110	130	160	180	200	220	230	250	260	270	290	310	320

 

Target Throttle Plate Position (Requested Torque)

0	20	40	60	80	100	120	140	160	180	200	220	240	260	280	300	320
0	0.4	1.6	3.5	6.3	9.8	14.1	19.1	25	31.6	39.1	47.3	56.3	66	76.6	87.9	100

I was curious on how much throttle Cruise control gives with each map. For these map traces I started at 65mph and used cruise control (press all the way up) to increase speed to ~75mph.

 

Stock DBW Map Trace:

http://legacygt.com/forums/attachment.php?attachmentid=262112&stc=1&d=1519008371

 

Linear DBW Map v1:

http://legacygt.com/forums/attachment.php?attachmentid=262113&stc=1&d=1519008371

 

In Both cases I see cruise use up to 39% TPS (throttle body plate opening). Linear map actually ends up using TPS then even the stock map.

 

Which in my opinion is still too aggressive for just wanting to increase cruise speed. Warning, throttle control is all very subjective, I personally don't like to be thrown into the back seat from too much torque with Cruise Control, I have manual throttle pedal override for that.

Nice. I might experiment with these over the weekend "Twitchy" is definitely a good word to describe the low load throttle response.

Nice let me know how it turns out for you, I've been playing with other maps too and keep on going back to that one, it's the most natural feeling one so far.

I wanted to see how much throttle is needed to maintain the car at 70mph. As per this trace, around 10% TPS.

http://legacygt.com/forums/attachment.php?attachmentid=262114&stc=1&d=1519008479

 

Next I wanted to see if the car actually needed 10% TPS to run the car, or it was simply there because Cruise Control was being generous. I modified the 70mph columns to have much less timing (red squares). Surely enough, the car needed around 10% TPS to maintain speed at 70mph (red numbers).

 

Interstingly enough the Pedal Requested torque table shifted to accomodate the less throttle, which means that CC uses Accel Pedal Requested torque table too and fools the ECU to think the physical pedal is being depressed.

 

With this information now I know that both stock table and new table are still too liberal with trottle when accelerating with cruise control (30-39% TPS). Getting it downt to 20-30% should smooth it out. The trick is to not make the car jerky when not using cruise control in those cells.

I'm just over here like, "please fix my 2250rpm hesitation!" lol

 

 

Good work though!

I'm just over here like, "please fix my 2250rpm hesitation!" lol

 

 

Good work though!

 

What conditions do you see it under? I personally don't think I saw it on my stock map. Or maybe I'm just so used to it by now

Nice let me know how it turns out for you, I've been playing with other maps too and keep on going back to that one, it's the most natural feeling one so far.

 

Tried your "new map" in post #1 this morning. This is only based on one drive, but it does seem smoother going up my driveway in the morning. Usually during that low speed / low load drive in 1st gear it is a bit twitchy, but the new map tamed it quite a bit. Thanks!

Here is an experimental map, I was testing even less requested torque, to see how much cruise control wanted to use to accelerate. This map was smooth for Cruise control acceleration, but was not good for any other kind of driving, just not enough throttle.

 

If you compare it to version 1 map, you will see that max TPS used was down to 31.6% version 39.1%, and Max Accel pedal angle is at 50%. This made me wonder if ECU had a limit on how much Accelerator Pedal it would use.

http://legacygt.com/forums/attachment.php?attachmentid=262116&stc=1&d=1519008754

 

 

I also wanted to see which map cruise control actually used, it's commonly thought that it uses Target Throttle Plate Position table, which I believe is inncorect. From my experience so far, it seems like the ECU just emulates accelerator pedal voltage when you press up on cruise control switch.

 

In this map I forced 100tq max on most columns, which made it very tricky to drive to the interstate (either you WOT or you dont move).

http://legacygt.com/forums/attachment.php?attachmentid=262117&stc=1&d=1519008754

 

Talking about a boring acceleration, it took about a minute to get from 65-70, and another 5 to get to 75mph... As you can see the ECU was not restricted to 50% pedal, it went much further trying to get more throttle in the engine.

 

With this in mind, ECU uses the minimum amount of accelerator pedal angle needed to accelerate while in cruise control, it just so happens that OEM map is so jumpy that it ends up feeding much more throttle then it actually needs. The next task will be figuring out how to make a non twitchy cruise control map while maintaining good city drivability.

I think there is a common issue with a stumble/hesitation at light load acceleration just above 2k rpm... Nothing serious but annoying. I've heard explanations from fuel lines to o2 sensor to DBW maps. Ughh.

 

Good work though, I might have to try out your v1 map soon.

I think there is a common issue with a stumble/hesitation at light load acceleration just above 2k rpm... Nothing serious but annoying. I've heard explanations from fuel lines to o2 sensor to DBW maps. Ughh.

 

Good work though, I might have to try out your v1 map soon.

 

This should make your life little easier to build the table. Top line should stay the same, copy and paste the bottom line of each code section.

 

Version 1 linear map:

Requested Torque (Accelerator Pedal)

0	7.1	14.3	21.4	28.6	35.7	42.9	50	57.1	64.3	71.4	78.6	85.7	92.9	100
0	75	110	130	160	180	200	220	230	250	260	270	290	310	320

 

Target Throttle Plate Position (Requested Torque)

0	20	40	60	80	100	120	140	160	180	200	220	240	260	280	300	320
0	0.4	1.6	3.5	6.3	9.8	14.1	19.1	25	31.6	39.1	47.3	56.3	66	76.6	87.9	100

Quick question.

 

Is it safe to just copy / paste the tables above on a non-stock car? Just want to make sure changing those tables won't have any negative consequence.

 

Thanks.

Quick question.

 

Is it safe to just copy / paste the tables above on a non-stock car? Just want to make sure changing those tables won't have any negative consequence.

 

Thanks.

 

Yup should be just fine. The reason it would be just fine is, your timing and fuel tables are based on incoming air (grams per second). The only thing that this could affect is tables that are based on TPS, but I haven't really seen any of them.

Thanks for the quick response.

 

Last question. Is there some easy way to copy/paste your tables or do I have to type each field in?

OOOH I got it, NVM re-read your posts, let it digest, I got it!

I know exactly what you mean and have posted about it before. If you have 100whp or more over and above stock, the throttle angle change to return you to target speed is going to be enough to glue you and your passengers to the seats. I don't mind so much, but if I have people in the car I do not hit 'resume' if I am 20kph or more below the set speed unless I want to hear them complaining.

It would probably be better if the cruise control tables could be defined. There must be a table that bumps requested torque up by x amount for y amount of 'accel' button pushing, or for using 'resume' at speed x amount below target speed set y.

From my testing it seems like ECU sees it as you pressing the pedal. The longer you hold it the more throttle it gives. With my very dumbed down tables, since I had to hold the CC accel for like a minute it would reach the equivalent of pressing the gas pedal to 70%, while stock table goes to 35% to accelerate to the same speed (75mph).

 

What your saying makes a lot of sense, with more power the stock throttle happy DBW table needs to be remapped. Give the linear table a shot, it should be a little more graceful, if it's still too much you can reduce the requested torque.

I'm wondering this:

 

I have an auto, by messing with these tables do you think I would be able to trick the TCU into shifting at different times.

 

Example: lower the actual throttle opening with more pedal input resulting in the transmission shifting harder with more line pressure.

 

Did that make any sense?

 

I'd like to trick the TCU into adding line pressure for my 1-2 and even the 2-3 shift when I am not accelerating hard.

You can change shift behavior by modifying RT values at different pedal positions, yes. Basically, more RT will cause shifts to occur at higher rpm and with more line pressure. If Calculated Torque tables have been defined for your ECU (or even exist), you can also increase the CT values for particular load and rpm cells to increase line pressure there.

In for reviews of this style of throttle mapping from anyone who has tried it... I still need to give it a go, just wondering if it's worth it (sorry russian lol)

I should make myself a table where the throttle is cut to about ~20% where it should be, then make it super aggressive at the rpm of my PT6266's full spool and EWG opening. Have a friend test drive it. He'd be like, "Dude, why's your car so slow?" Hits 4000 rpms, wastegate opens. "HOLY SH**!!! Vtec kicked it yo!"

Just an update, I've switched back to factory map for myself. With not seeing any real fuel economy gains and having 0 WGDC in low throttle levels factory DBW map was a little more drivable.

 

I think I will make a linear map similar to the factory map (so that keeping the throttle at one angle doesn't keep vary the TPS) Once I go higher power will probably tune down the DBW table again.