E78 Boost Control

Hello, I am looking for some advice for best method of control boost.

Working on a 1.4L Turbo.

I have set the Boost Max Limit to 240kpa. And it will sometimes spike over the limit. It sometimes spikes and does some sort of cut. And then sometimes it will spike and pull real good. But on every pull that it does pull through and doesn't hit some sort of cut. The desired boost will start dropping and then actual boost seems to follow desired from there on out. But seems to be a bit out of control when it comes into boost.

So I am looking for the best method of controlling boost. And also how to keep it to carry boost all the way out to redline. After 5000 rpms, desired and actual boost keep dropping all the way out to redline.

I have upped all the torque limits tables under torque management. (Is it best to max those tables out or just set just high enough for torque management to not interfere)

I have also upped the driver demand table from 80%-100%. (Also same question, should I set those tables maxed out or set them to a actual torque number suited for these engines)(And also should I raise entire rpm range or just when boost full comes in on these engines)

I have also raised Knock Airmass up to 1g @ 0*. (Should I raise higher)

Should I need to adjust any of the following (Wastegate Open Boost, Base DC, Base DC Scav, Proportional Gain, Integral Gain, Derivative Gain, Pressure Delta Factor, Failure Airmass)

Should I raise Wastegate DC Max?

And how about the Turbo Overspeed Tables? I have raised the Overspeed Limit Min to .75g, and raised the Pressure Ratio Max to 3g. (Need opinion on whats best for those tables and also do we need to adjust Max VE)

Just wanting to fully understand how to control boost best on these ECUs, I have a wideband installed in the car, I have fueling and spark dialed in very well. Just looking to get a better control of boost and to fully understand the system. I have hit the max of the MAP sensor reading of 255kpa a couple of times which will max injectors out, so did not like that. So I did not have a boost gauge on it read the max boost, but was more than 22psi. And would honestly just want to command 240kpa from the moment I go WOT all the way to redline, and for the vehicle to actually boost 240kpa that whole range.

Thank you in advance for any tips/help/or ideas.

The key is to not get carried away on the tables because a lot of them are used in prediction and calculation.
Usually the table that is forgotten is the knock airmass. As another user just found out on an ATS if you forget to bump that threshold just over your actual airmass you can loose control over the ETC Motor and possibly other output devices.
Its been a while since i went into my sonic 1.4T but i do remember only adjusting tables by means of using minimal value to achieve desired output. Some tables were like the LNF where there wasn't a whole lot of clarity so keeping values small helps keep the map textures smooth.

determine max desired boost and calculate the pressure delta, baro to mani kpa and set the Boost Pressure Delta Factor accordingly so you do not undercut your desired boost pressure.
Prop/Int/Der Gains can be adjusted to help aid in boost control response but generally i leave them stock until i figure out how to control the rest of the ecu.
If you raise WGDC Max allowed signal keep in mind you can fry a solenoid by running higher than 93% cycle for long duration's of time. Most of your WGDC control should occur between 70-90% if the rest of the ecu has been configured to demand air properly. At least thats the sweet spot for solenoid life span.

I wont comment any further because i dont remember what i did to control the other tables. Sorry mate, you dont need bad information.

Thank you for the reply and information. I am going to be spending some time with the E78 ECU. So if I get this thing figured out and can explain exactly what each table does and how it affects the vehicle. I will definitely do a write up on it. But until then, any other help along the way is always appreciated.

Thank you

Quote:

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Originally Posted by Mark@TuckerPerformance

Thank you for the reply and information. I am going to be spending some time with the E78 ECU. So if I get this thing figured out and can explain exactly what each table does and how it affects the vehicle. I will definitely do a write up on it. But until then, any other help along the way is always appreciated.

Thank you

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I'm working with the E78 in my chevy spark and I am adding a turbo from the 1.4 Cruze. Did you end up doing a write up on your findings? Any info is greatly appreiated!

Their is quite a bit of info tuning the E78 pcm in the Cruze and Sonic just on this forum alone with a search. The big thing is with these is not to go nuts just maxing out every torque management table and raising the knock airmass table to some ridiculous number is also not needed! A lot of the torque management starting with the driver demand tables is used in prediction and calculation just like cobaltssoverbooster has already stated. I have the boost I want from mine while keeping the throttle 100% open the entire time on a wot run. In short don't need to use a sledge hammer when a tack hammer will do.