LNF Wastegate Control

Hey guys. Just recently picked up a '08 LNF Cobalt and have been learning a bunch. Have a turbo '01 LS1 SS so I'm not new to tuning but as everyone says this ECM has some tricks.

Followed most of the guides here and its running well but I am commanding 95% WG DC and only seeing 75% DC for most of the run. (long log file but its towards the end). Boost goes to about 22 psi and holds okay but then tapers off after 5500. Boost holding seems decent and inline with what others have on the same stock turbo, just wondering why the commanded doesn't match the actual for the WG DC?
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The turbo starts to die off up top. That's why raising the rpm limit is almost pointless because it's a quicker run shifting it lower. You aren't doing anything wrong most likely (I haven't looked at your uploads). It's most likely just the turbo.

Take a look at your pressure limit settings and the pressure RPM factor. Both are limiters. Also, I'd suggest not pushing the stock turbo so hard with your current WG settings. You'll get it to hold pressure better and actually be a bit quicker.

Both limiters I suggested are listed under TM - > Turbocharger

in the past i would recommend 255 dals as a general blanket statement because thats what it used to take with minimal table access.
now i set my dals up to around 235 for starters and work around with everything else to see where i can get it to land. if i hit 90% wgdc without hitting my target boost i end up raising the dals by 5 until im in a wgdc% range i can live with (typically i like it in the 85% range).

because the table is so small, this helps massively with power jumps. what i mean by that is from one cell to another i can have a smaller gap making the table transition smoother which is critical for getting rid of unwanted issues like kr.

others can comment further

Pressure RPM factor was it. My pressure limit was already at 280 kpa. Previous boost peaked at 22 and went to 18 psi at 6200. This run with the RPM factor upped, boost pegged stock sensors and held 20 psi at 6200. Time to install the GMS1 sensors I have in the tool box! I'll scale back the WG dc % to even things out. Did record my first 60-100 in the 4's, 4.69s to be exact on an unhappy clutch. When looking at logs, what commanded DC is too much? I've can see 95% from 5500-6200? Not wanting to burn out the solenoid. Just wondering what's okay from a durability perspective.

For those reading this later and since I had trouble finding the info. Pressure RPM Factor table works like this:

Lets say value is 2.45. Take atm pressure (14.7 psi) * 2.45 = 36.0. That's absolute pressure so then subtract atm (-14.7) = 36.0 - 14.7 = 21.3 is the boost limit for that RPM point.

You dont need the GMS1 sensors for more boost.

And yes, you are correct on your explanation of Pressure Factor. Lots of other engines use the same or very similar tables too, so it's a good one to understand.