Boost control advice

[dart440]

Had my Dart at the track and finally got some decent passes. It has Gen3 Hemi with a 76 mm turbo. The boost seems to build slow in low gear. Are there any settings I can tweak to make it build faster? I am traction limited, so I don't want too much power of the line. The boost control seems to do a good job maintaining target, I just want it to build faster. I am using the DIY Autotune boost solenoid and a 60mm Tial waste gate. MS3x COP with factory coils.

Also, some of the logs show a loss of sync (just one instance) that seems to happen on start-up. It is there at the beginning of the log and doesn't count up. Any ideas?

Please look over my run and feel free to offer suggestions.

[Matt Cramer]

I wouldn't worry about a loss of sync while cranking if the engine doesn't kick back or otherwise have trouble starting. Cranking is the hardest time for it to sync.

The boost target table is weird - the values should be in absolute kPa values, but they seem to have been entered as psi of boost.

[dart440]

Yes the boost table is in PSI. I didnt know it was supposed to be in kPa

[16vboost]

Haha. So you were running spring pressure the whole time. That explains why the thread didn't read "boost control tuning driving me nuts". You'll probably find that tuning the PID values can be challenging.

As for the slow boost build, that probably has more to do with tour hardware, cams, turbo, etc. I've heard of running more timing to help spool the turbo faster but can confirm.

-Alex

[muythaibxr]

Boost control should not drive you nuts on the latest release code.

It should be even better still on the latest alpha, but I can't recommend using that if you're less experienced at this point.

Ken

[pit_celica]

I've heard of running more timing to help spool the turbo faster but can confirm.

-Alex

It's the opposite. Running less timing in the spool-up RPM/MAP zone should decrease spool time. It's because less ignition timing increase EGT, and high EGT increase the energy that can drive the turbine. The problem with this approach is that it requires a signifiant low timing number to generate enough heat to decrease spool, and this low timing number will decrease the engine power. So, your turbo will spool faster, but your car will accelerate more slowly. Maybe there is a compromise between both situations. It needs to be tested/fine tuned.

Sam

[16vboost]

Boost control should not drive you nuts on the latest release code.

It should be even better still on the latest alpha, but I can't recommend using that if you're less experienced at this point.

Ken

It is definitely tune-able. I've had it working pretty well since 3.2.8 and just went to 3.3.1 with minimal re-tune.

Are you suggesting that he tries tuning with the sensitivity slider instead of PID constants? Aside from the slider and "higher duty cycles mean more boost" what has changed in the code? Isn't it still type B PID?

Why is the latest alpha even better? Because it doesn't enter PID until getting close to the target?

-Alex

[muythaibxr]

The latest alpha of ms3 is easier for people who are used to ideal pid because it is using the ideal pid equation. Other than that there were the changes to hold the wastegate closed until you are close to target and the addition of an initial value table in ms3 1.3 and the ms2 betas. In ms3 that table becomes a bias table.

[dart440]

Thanks for the advice. I am leery to install the latest software because my brother(ShelbyZ24) tried it and it caused a severe misfire that could only be fixed by reinstalling the older firmware. We both use the 32-2+2 wheel. Does the latest firmware address this problem?

[dart440]

BTT

[muythaibxr]

Thanks for the advice. I am leery to install the latest software because my brother(ShelbyZ24) tried it and it caused a severe misfire that could only be fixed by reinstalling the older firmware. We both use the 32-2+2 wheel. Does the latest firmware address this problem?

I was not aware of this problem. So unless James knows about it, it's unlikely that any newer firmware addresses it.

Ken

[muythaibxr]

Thanks for the advice. I am leery to install the latest software because my brother(ShelbyZ24) tried it and it caused a severe misfire that could only be fixed by reinstalling the older firmware. We both use the 32-2+2 wheel. Does the latest firmware address this problem?

Did you or your brother report this issue officially?

We can't fix what we don't know about...

Ken

[dart440]

He had a query on this forum. Is that concidered official? Or is there another method?

[jsmcortina]

He had a query on this forum. Is that concidered official? Or is there another method?

When and where?

I was only aware of this post today when Ken pointed me to it and he only noticed last night.

Unfortunately we are not psychic. I am not aware of seeing any posts from either of you in any of the alpha/beta/release topics that caught my attention about a problem.

James

[dart440]

Here is the link http://www.msextra.com/forums/viewtopic ... 31&t=54196
I understand that it must be near impossible to see all posts by everyone. Thanks for all your hard work and help. Without the resources of this forum, I would still be pushing my car in and out of the garage! Hopefully there is no issues with the latest firmware as I would love to try out all the new features

[dart440]

I just installed the 1.3.1 firmware. Car runs good. I will play with the boost control at the track soon.
Thanks

[dart440]

Boost control worked perfectly. Hit my target and held it through out the run. I didn't even touch the default setting! Great job guys!
BTW the car ran 9.47 @ 144mph.

[nathaninwa]

That's great news! Does the 1.3.1 use the same boost control as 1.4.1? I really like the new stuff if it is. Nice numbers too!

[muythaibxr]

It does not. 1.4 (there is no 1.4.1) uses a different PID algorithm that changes the initial value table to an always on bias table with "ideal PID" instead of "type B PID" In laymen's terms, 1.4 should be more consistent in differing situations.

[Zaphod]

As I already wished for in another thread - could we please get a boost control (PID) tuning advice stickie for the newer PID algorithms - (maybe in combination with a little list of "what firmware uses what kind of boost control")

I have seen different threads also in other boards, where people try to tune the boost control with the "old style" tuning and can't get sensible results - until someone notices that they are using the new firmware, and have for instance not set their inital duty table.

It would be good if we could get such a sticky topic in this Tuning part of the board, because in the one thread about the new boost control algorithm the tuning advices are very hidden and it's not easy to see, which firmware they are about...

Thanks in advance!