So I was tuning today down at sea level on my 3-port, and I decided to reduce the max upward and downward WGDC% values, along with the Turbo Boost Error Correction, so the correction swings are reduced (being that the 3-port controls the wastegate alone, a single-percentage adjustment makes a much larger difference than with the dual-solenoid setup).

Well, after changing the Max Downward WGDC% to -32% (-64% by default), I got some crazy results where the ECU wanted to ADD 45% WGDC at WOT, giving me 90+% WGDC on full spool. This resulted in boost spikes of around 40 psi at OVER 400% load. Gladly my tune is conservative up top, and my fueling adequate, so the worst I saw was 1 knock count and one hard fuel cut once I hit the boost limit.

Needless to say, I pulled over, adjusted the value back to -64%, and all was well! Soooo it appears as though this mapped value does not control what we think it does and actually changes how the boost control operates.

In short, leave this value at -64%

 

Yikes!

It's why I'm sticking with what works simply for me right now, just a Dual switch MBC.

 

Sounds like the scaling might be incorrect.

- Bryan

 

My bad. It is indeed a scaling error. Find the "OffsetWGDC" scaling in the evo10base.xml file, and replace it with:

<scaling name="OffsetWGDC" units="%WGDC Change" toexpr="(x-128)/2" frexpr="x*2+128" format="%.1f" min="-64" max="63.5" inc="0.1" storagetype="uint16" endian="big"/>

Bryan, the scaling is also incorrect in the Evo 8/9 base files as well.

 

Lol even on vacation you don't quit.

 

So if I put the correct scaling in, do I need to change anything in the tables of my rom?

 

Its more interesting than most stuff on TV, I've seen most all the new movies worth watching, and my baby has gone to bed. I heard its dumping snow in the Tri-Cities. Hope the drive to work is ok on Monday.

Someone just pointed out to me that the scaling definition above kills the Max Upward WGDCC table. Fixing up the ECUFlash xml files is a little more complicated now because two scaling definitions are needed. Replace the "Offset WGDC" scaling table with the following two definitions:

In the evo10base.xml file, its necessary need to change the "Max Upward WGDCC" table scaling to "OffsetWGDC-8", and then change the "Max Downward WGDCC" table scaling to "OffsetWGDC-16". If you don't know how to do this, you'll need to find someone who can do it for you.

NOTE: These changes are only necessary if you intend to mess with the "Max Downward WGDCC" table.

 

Thanks mfred, I plan on tuning for a 3-port soon, and I want to have this for if I (or someone else) think I need it. It will already be good to go.

 

It's all gone now. I think the X was so much fun drifting around my street on the summer tires. I hope you got some free time soon. I have decided it is time to convert the talon over to speed density. I am placing my order for everything probably tuesday or wednesday.

Sorry for the thread jack.

 

what is the max downward WGDC table used for?

 

If the snow is gone, then I can finally do my t-case and rear diff fluid change. SD for the Talon sounds good. I'll give you a call after I get into town.

Its actually max downward WGDC correction. It limits how far the WGDC can be reduced below the baseline value. I've never had a reason to change it from the stock value.

 

ok, i've never heard of anyone using it besides UT evox so i wasn't sure. UTevox why did you attempt to use it? and what does it do?

 

He explains in the first post why he tried it.