Fun with DBW, or how I learned to stop hating the gas pedal

[KoolBRZ]

As I've built up my car with intake, exhaust, OFT, and etc. my gas pedal has gotten touchier and touchier.10% throttle hardly moved the car with stock equipment, now it lunges forward with a ripping sound of slipping rubber. That's fine, but now the A/T trans short-shifts every gear because I'm not giving it enough pedal to stay in gear longer. So it was time to research Drive-By-Wire, (DBW) to adjust the sensitivity, (scale) of my gas pedal.

There is some information on the forum here, but I don't care how it works, or what certain tables mean and how they work together. I just want to know, what do I change to make my pedal less sensitive? Hours of research later, still no answer. I'm looking for which table in RomRaider I need to change. No such luck.

So I figure Shiv probably changed the DBW tables with his tunes, so why not compare them to stock? I was careful to apply the stock definition before opening the stock tune, and the correct OFT definition before opening the OFT DBW tables. I compared them and there is only one table changed, the Requested Torque A table. Here's my first attempt, DBW1, below, with Shiv's table, and the stock table, for comparison.

End result, it works. there is less whiplash shifting manually, and better yet, it almost shifts normally in automatic mode. I'm getting better mileage also, since I can keep the throttle more steady now.

[KoolBRZ]

Questions for Kodename47 and Steve99, and other master ECU editors out there, is this table really the only one I need to change? What about "Sport" mode? Which table does that use? I'd like to have a tame setup, economy mode, and an extreme setup, sport mode. Can I do that with these DBW tables in RR, or are those modes determined elsewhere?

[Wayno]

Copy the contents of "Requested Torque B" from any MT rom and leave everything else as is if you want a more linear pedal.

[KoolBRZ]

Originally Posted by Wayno

Copy the contents of "Requested Torque B" from any MT rom and leave everything else as is if you want a more linear pedal.

That's not the problem. My car is an A/T, so a linear throttle would actually drive worse. You M/T drivers can just give it more gas to keep from stalling, but an A/T is under load any time it is in gear, so too little torque, it stalls out. An A/T car needs a really curvy throttle curve

My car is making more power than stock, but my transmission is short-shifting because the pedal position I'm using is higher because it's making more power. I wanted to keep the same accelerator curve, but reduce the power produced in the first 40% of pedal travel, so my trans would shift correctly again.

I reduced the power produced with the DBW requested torque A table, instead of pulling timing or wasting fuel, so I can still have all the power in the last 60% of the pedal travel. The first 40% is what I use most for city and highway driving. The transmission is shifting smoother now, it's easier to keep a steady speed on the highway, and I'm getting better mileage too.

[Wayno]

All your threads make other AT drivers look bad, please go away.

[KoolBRZ]

Originally Posted by Wayno

All your threads make other AT drivers look bad, please go away.

You're entitled to your opinion, wayno, but every A/T owner is going to run into the same problem when they build up the power in their cars.

[Kodename47]

I'm not 100% up on the throttle mapping tables. The sport mode may be carried over from the WRX SI Sport selector and not used, or it maybe cruise and non cruise. We don't have throttle selection so you can't set something switchable.

If I'm honest you need to know the relationship between the DBW tables to then truly understand what changes to make. Then you will be able to make educated changes, however it sounds like what you have works and that is the table I would make the changes to.

[steve99]

The dbw throttle setting is something i have not touched. I am lead to believe by those far more knolegable than myself that it a bit od a dark art adjusting those tables. As @Kodename47 says if it works for you thats good just make small changes and test the results and be prepared for some undesirable or unexpected effects.

[Toyota John]

I would really like to start looking into this. I am fairly happy with the OFT DBW tables I used for my tune but I would really like to under stand what they all do. I started looking into this last spring but ended up moving on to something else to tune. There are posts on romraider forums about this where some one tried to explain how each table worked but ended up with about the same out come as the OFT. I am guessing that most tuners don't go into much detail with this and flash a similar map to everyone else. With ecutek I can log peddle position and throttle position. So maybe this spring with the roads clean up I will start working on that. I still need to balance my injector scaling but maybe this is next.

[KoolBRZ]

Originally Posted by Toyota John

I would really like to start looking into this. I am fairly happy with the OFT DBW tables I used for my tune but I would really like to under stand what they all do. I started looking into this last spring but ended up moving on to something else to tune. There are posts on romraider forums about this where some one tried to explain how each table worked but ended up with about the same out come as the OFT. I am guessing that most tuners don't go into much detail with this and flash a similar map to everyone else. With ecutek I can log peddle position and throttle position. So maybe this spring with the roads clean up I will start working on that. I still need to balance my injector scaling but maybe this is next.

I'm not sure this would be much of a priority if you're driving a manual. I know from experience though, that the automatic does not compensate for any increase in power. As the power increases, the trans shifts at lower and lower RPM's, lugging the engine under power. The only alternative is to shift manually.

If any other automatic owner with an OFT wants to try this out, just PM me with your email, ROM ID, and preferred tune, and I'll send you the tune with my modifications added to it.

[phrosty]

I'm also short-shifting pretty bad now that it's snowing and I can't keep my foot down a little more. Been considering attempting something like this myself.

[KoolBRZ]

Originally Posted by phrosty

I'm also short-shifting pretty bad now that it's snowing and I can't keep my foot down a little more. Been considering attempting something like this myself.

This will be a lot more drive-able in the snow than your current tune. I've lowered the starting point from 152 to 120. I wonder how low I could go before it bogs down on the 1st to 2nd shift? Send me a PM and I'll email you what I've got, if you've got an OFT that is.

[KoolBRZ]

Here's a screenshot of my newest DBW map. 10% starts at 100, rather than 152. This should be a good mother-in-law, girlfriend, or valet mode. The question is, will it run too crappy to drive. I'm flashing it now. I'll give feedback later.

[Poodles]

Originally Posted by KoolBRZ

That's not the problem. My car is an A/T, so a linear throttle would actually drive worse. You M/T drivers can just give it more gas to keep from stalling, but an A/T is under load any time it is in gear, so too little torque, it stalls out. An A/T car needs a really curvy throttle curve

This isn't how an A/T works... If it's stalling, there's something VERY wrong.