DBW Traction Control

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redcycle13
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DBW Traction Control

Postby redcycle13 » Tue Sep 04, 2018 2:25 am

I'm working on dialing in traction control on a high horsepower fox mustang with a Procharged LS7 engine. As you can imagine putting this power down on the street is difficult. I've started by implementing a generic timing correction that starts pulling timing as wheel slip is encountered with the intention of keeping the car from cutting cylinders. It seems that I am either not pulling enough timing (but I am already pulling quite a lot), or this is just not an effective way to keep the car from reaching the cylinder cut threshold. So I have been toying around with the idea of limiting the throttle body opening percentage based on wheel slip. I was hoping someone had used this strategy effectively, and could provide some input on whether the DBW is fast enough to catch accelerating wheel slip. In other words if I started closing the throttle body at 6% wheel slip along with already pulling timing if that might be enough to keep the cylinder cut from happening at 12% wheel slip. I know every car will be different based on amount of traction available, and the power your trying to harness, but some thoughts on the subject would be nice.

I have seen on a supra forum where this was being used, but it didn't provide much detail.

Mobne_s13
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Re: DBW Traction Control

Postby Mobne_s13 » Tue Sep 04, 2018 6:03 pm

Im really sure Bmw use this strategy on their Oem engines.

Should work well. But I have no clue if Haltech’s software can do it atm.
You can do a lot with the generic tables. See if it works and if it does let us know :)

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HaltechMatthew
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Re: DBW Traction Control

Postby HaltechMatthew » Fri Oct 19, 2018 2:30 pm

Map your MaxDBW table over wheel slip. Works for NA or supercharged engines. Works not so well with turbo cars as it stalls the turbo and you need to respool. Ignition cuts are usually much faster and work better.

Mobne_s13
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Re: DBW Traction Control

Postby Mobne_s13 » Mon May 27, 2019 2:16 am

Is there any guide in setting up the traction control?
My engine is strong and when I lose the traction it hits the limiter right away.

I tried the default settings but it was way to harsh. Felt like I lost a lot of the acceleration.

I find that there is really not much to do in the settings besides telling the ecu the slip desired.

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HaltechMatthew
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Re: DBW Traction Control

Postby HaltechMatthew » Mon May 27, 2019 9:38 am

Normally you just need to play with the slip table, and if it is hurting your acceleration you probably need to relax it a little. You can also add an ignition generic table to map retard over wheel slip to take the edge off it.

Throttle limiting is something I leave for excessive wild wheel slip. Cutting the air flow early tends to bog things down.

Mobne_s13
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Re: DBW Traction Control

Postby Mobne_s13 » Tue May 28, 2019 5:46 pm

Thanks :)

Would you mind posting pictures of tractioncontrol setup page, the slip table and the generic ignition correction on a working setup?

I know all cars are different and user want different things. But as a guideline.

Mobne_s13
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Re: DBW Traction Control

Postby Mobne_s13 » Wed May 29, 2019 5:38 am

HaltechMatthew wrote:Map your MaxDBW table over wheel slip. Works for NA or supercharged engines. Works not so well with turbo cars as it stalls the turbo and you need to respool. Ignition cuts are usually much faster and work better.


If i do this, then this will always be active? How will my MAXdbw table know if my traction control is active or not? Or is the slip only calculated when TC is ON?


Edit: If its always calculated, i can solve that with adding 4d map with switch state on and off, and only use less dbw when tc is on.

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HaltechMatthew
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Re: DBW Traction Control

Postby HaltechMatthew » Wed May 29, 2019 9:28 am

Calculate and no slip then full throttle. Not Calculated the channel does not work so still full throttle. I do it this way on my own car, where the throttle will intervene only when slip is high, like 20% or so.

In general start with around 10% slip and move up or down to see how your application works. Usually a little more at low speed to prevent activation when turning corners, and lower at high speed, around 5 to 7 I find works well.

Mobne_s13
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Re: DBW Traction Control

Postby Mobne_s13 » Wed May 29, 2019 5:18 pm

As asked before, would you mind sharing the tc setup and tables on your car?

Pictures say more then 1000 words.

Would be really useful for n00bs like me :)

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HaltechMatthew
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Re: DBW Traction Control

Postby HaltechMatthew » Thu May 30, 2019 10:21 am

Slip1.png
Slip1.png (11.65 KiB) Viewed 286 times


Nothing special. Start with 10 everywhere and adjust to suit.

Mobne_s13
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Re: DBW Traction Control

Postby Mobne_s13 » Thu May 30, 2019 10:43 pm

I would like to set this up so i can do a 0-100kmh faster.

I guess this is not what it is designed for. Because i have som real trouble getting it working as i want.
Its so agressive engine bogs when i go of the launch at 4500rpm.

This is the last settings I where at. It did come off the "start" but not in an improved way.

Is there any difference in cut response time between injection and ignition?

tc1.PNG
tc1.PNG (9.89 KiB) Viewed 275 times


tc2.PNG


tc3.PNG

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HaltechMatthew
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Re: DBW Traction Control

Postby HaltechMatthew » Fri May 31, 2019 9:19 am

There has to be. Fuel goes in one crank cycle ahead of time so you are always delayed one cycle compared with fuel cuts compared with ignition cuts.

Mobne_s13
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Re: DBW Traction Control

Postby Mobne_s13 » Fri May 31, 2019 6:43 pm

HaltechMatthew wrote:There has to be. Fuel goes in one crank cycle ahead of time so you are always delayed one cycle compared with fuel cuts compared with ignition cuts.


But one cycle? Would you notice that?

I mean how many rpm can the engine gain on one cycle only? It fires 6 times on one cycle in my case. So 2 turns.

M3 engine is a well tuned machine, light flywheel also. It gains rpm fast. Is there any possibility to estimate how many rpm it could gain on one cycle Wide open throttle?


I would like to see the option for all revlimit options to cut both fuel and ignition.

If there is only one cycle of fuel being injected in the manifold the exhaust bangs should be minimal.

Therefore having the response from ign cut and still not making high emap pressures.

Please add this.

If you look at my setup, can you identify why it’s cutting so harsh? It acts like a hard fuelcut for overboost almost. It’s not engaging smooth.
Should I try removing ramp out? Would this make it respond faster?

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HaltechMatthew
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Re: DBW Traction Control

Postby HaltechMatthew » Mon Jun 03, 2019 9:38 am

Absolutely no idea how it will react on other cars, they all act a little different. But for almost all cars I have done with traction control, including some with 4-digit HP I have not touched anything other than the slip table.

You may or may not see a delay difference between fuel and ignition cut, but it is there none the less.

Mobne_s13
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Re: DBW Traction Control

Postby Mobne_s13 » Mon Jun 03, 2019 4:38 pm

And on your setup you always use ignition cuts?
No loud exhaust bangs?


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